Conflicts:
include/linux/mm_types.h
mm/huge_memory.c
I removed the smp_mb__before_spinlock() like the following commit does:
8b1b436dd1 ("mm, locking: Rework {set,clear,mm}_tlb_flush_pending()")
and fixed up the affected commits.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We saw many list corruption warnings on shmem shrinklist:
WARNING: CPU: 18 PID: 177 at lib/list_debug.c:59 __list_del_entry+0x9e/0xc0
list_del corruption. prev->next should be ffff9ae5694b82d8, but was ffff9ae5699ba960
Modules linked in: intel_rapl sb_edac edac_core x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul ghash_clmulni_intel raid0 dcdbas shpchp wmi hed i2c_i801 ioatdma lpc_ich i2c_smbus acpi_cpufreq tcp_diag inet_diag sch_fq_codel ipmi_si ipmi_devintf ipmi_msghandler igb ptp crc32c_intel pps_core i2c_algo_bit i2c_core dca ipv6 crc_ccitt
CPU: 18 PID: 177 Comm: kswapd1 Not tainted 4.9.34-t3.el7.twitter.x86_64 #1
Hardware name: Dell Inc. PowerEdge C6220/0W6W6G, BIOS 2.2.3 11/07/2013
Call Trace:
dump_stack+0x4d/0x66
__warn+0xcb/0xf0
warn_slowpath_fmt+0x4f/0x60
__list_del_entry+0x9e/0xc0
shmem_unused_huge_shrink+0xfa/0x2e0
shmem_unused_huge_scan+0x20/0x30
super_cache_scan+0x193/0x1a0
shrink_slab.part.41+0x1e3/0x3f0
shrink_slab+0x29/0x30
shrink_node+0xf9/0x2f0
kswapd+0x2d8/0x6c0
kthread+0xd7/0xf0
ret_from_fork+0x22/0x30
WARNING: CPU: 23 PID: 639 at lib/list_debug.c:33 __list_add+0x89/0xb0
list_add corruption. prev->next should be next (ffff9ae5699ba960), but was ffff9ae5694b82d8. (prev=ffff9ae5694b82d8).
Modules linked in: intel_rapl sb_edac edac_core x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul ghash_clmulni_intel raid0 dcdbas shpchp wmi hed i2c_i801 ioatdma lpc_ich i2c_smbus acpi_cpufreq tcp_diag inet_diag sch_fq_codel ipmi_si ipmi_devintf ipmi_msghandler igb ptp crc32c_intel pps_core i2c_algo_bit i2c_core dca ipv6 crc_ccitt
CPU: 23 PID: 639 Comm: systemd-udevd Tainted: G W 4.9.34-t3.el7.twitter.x86_64 #1
Hardware name: Dell Inc. PowerEdge C6220/0W6W6G, BIOS 2.2.3 11/07/2013
Call Trace:
dump_stack+0x4d/0x66
__warn+0xcb/0xf0
warn_slowpath_fmt+0x4f/0x60
__list_add+0x89/0xb0
shmem_setattr+0x204/0x230
notify_change+0x2ef/0x440
do_truncate+0x5d/0x90
path_openat+0x331/0x1190
do_filp_open+0x7e/0xe0
do_sys_open+0x123/0x200
SyS_open+0x1e/0x20
do_syscall_64+0x61/0x170
entry_SYSCALL64_slow_path+0x25/0x25
The problem is that shmem_unused_huge_shrink() moves entries from the
global sbinfo->shrinklist to its local lists and then releases the
spinlock. However, a parallel shmem_setattr() could access one of these
entries directly and add it back to the global shrinklist if it is
removed, with the spinlock held.
The logic itself looks solid since an entry could be either in a local
list or the global list, otherwise it is removed from one of them by
list_del_init(). So probably the race condition is that, one CPU is in
the middle of INIT_LIST_HEAD() but the other CPU calls list_empty()
which returns true too early then the following list_add_tail() sees a
corrupted entry.
list_empty_careful() is designed to fix this situation.
[akpm@linux-foundation.org: add comments]
Link: http://lkml.kernel.org/r/20170803054630.18775-1-xiyou.wangcong@gmail.com
Fixes: 779750d20b ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert commit bb01b64cfa ("mm/balloon_compaction.c: enqueue zero page
to balloon device")'
Zeroing ballon pages is rather time consuming, especially when a lot of
pages are in flight. E.g. 7GB worth of ballooned memory takes 2.8s with
__GFP_ZERO while it takes ~491ms without it.
The original commit argued that zeroing will help ksmd to merge these
pages on the host but this argument is assuming that the host actually
marks balloon pages for ksm which is not universally true. So we pay
performance penalty for something that even might not be used in the end
which is wrong. The host can zero out pages on its own when there is a
need.
[mhocko@kernel.org: new changelog text]
Link: http://lkml.kernel.org/r/1501761557-9758-1-git-send-email-wei.w.wang@intel.com
Fixes: bb01b64cfa ("mm/balloon_compaction.c: enqueue zero page to balloon device")
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: zhenwei.pi <zhenwei.pi@youruncloud.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nadav reported KSM can corrupt the user data by the TLB batching
race[1]. That means data user written can be lost.
Quote from Nadav Amit:
"For this race we need 4 CPUs:
CPU0: Caches a writable and dirty PTE entry, and uses the stale value
for write later.
CPU1: Runs madvise_free on the range that includes the PTE. It would
clear the dirty-bit. It batches TLB flushes.
CPU2: Writes 4 to /proc/PID/clear_refs , clearing the PTEs soft-dirty.
We care about the fact that it clears the PTE write-bit, and of
course, batches TLB flushes.
CPU3: Runs KSM. Our purpose is to pass the following test in
write_protect_page():
if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) ||
(pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)))
Since it will avoid TLB flush. And we want to do it while the PTE is
stale. Later, and before replacing the page, we would be able to
change the page.
Note that all the operations the CPU1-3 perform canhappen in parallel
since they only acquire mmap_sem for read.
We start with two identical pages. Everything below regards the same
page/PTE.
CPU0 CPU1 CPU2 CPU3
---- ---- ---- ----
Write the same
value on page
[cache PTE as
dirty in TLB]
MADV_FREE
pte_mkclean()
4 > clear_refs
pte_wrprotect()
write_protect_page()
[ success, no flush ]
pages_indentical()
[ ok ]
Write to page
different value
[Ok, using stale
PTE]
replace_page()
Later, CPU1, CPU2 and CPU3 would flush the TLB, but that is too late.
CPU0 already wrote on the page, but KSM ignored this write, and it got
lost"
In above scenario, MADV_FREE is fixed by changing TLB batching API
including [set|clear]_tlb_flush_pending. Remained thing is soft-dirty
part.
This patch changes soft-dirty uses TLB batching API instead of
flush_tlb_mm and KSM checks pending TLB flush by using
mm_tlb_flush_pending so that it will flush TLB to avoid data lost if
there are other parallel threads pending TLB flush.
[1] http://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com
Link: http://lkml.kernel.org/r/20170802000818.4760-8-namit@vmware.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Reported-by: Nadav Amit <namit@vmware.com>
Tested-by: Nadav Amit <namit@vmware.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nadav reported parallel MADV_DONTNEED on same range has a stale TLB
problem and Mel fixed it[1] and found same problem on MADV_FREE[2].
Quote from Mel Gorman:
"The race in question is CPU 0 running madv_free and updating some PTEs
while CPU 1 is also running madv_free and looking at the same PTEs.
CPU 1 may have writable TLB entries for a page but fail the pte_dirty
check (because CPU 0 has updated it already) and potentially fail to
flush.
Hence, when madv_free on CPU 1 returns, there are still potentially
writable TLB entries and the underlying PTE is still present so that a
subsequent write does not necessarily propagate the dirty bit to the
underlying PTE any more. Reclaim at some unknown time at the future
may then see that the PTE is still clean and discard the page even
though a write has happened in the meantime. I think this is possible
but I could have missed some protection in madv_free that prevents it
happening."
This patch aims for solving both problems all at once and is ready for
other problem with KSM, MADV_FREE and soft-dirty story[3].
TLB batch API(tlb_[gather|finish]_mmu] uses [inc|dec]_tlb_flush_pending
and mmu_tlb_flush_pending so that when tlb_finish_mmu is called, we can
catch there are parallel threads going on. In that case, forcefully,
flush TLB to prevent for user to access memory via stale TLB entry
although it fail to gather page table entry.
I confirmed this patch works with [4] test program Nadav gave so this
patch supersedes "mm: Always flush VMA ranges affected by zap_page_range
v2" in current mmotm.
NOTE:
This patch modifies arch-specific TLB gathering interface(x86, ia64,
s390, sh, um). It seems most of architecture are straightforward but
s390 need to be careful because tlb_flush_mmu works only if
mm->context.flush_mm is set to non-zero which happens only a pte entry
really is cleared by ptep_get_and_clear and friends. However, this
problem never changes the pte entries but need to flush to prevent
memory access from stale tlb.
[1] http://lkml.kernel.org/r/20170725101230.5v7gvnjmcnkzzql3@techsingularity.net
[2] http://lkml.kernel.org/r/20170725100722.2dxnmgypmwnrfawp@suse.de
[3] http://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com
[4] https://patchwork.kernel.org/patch/9861621/
[minchan@kernel.org: decrease tlb flush pending count in tlb_finish_mmu]
Link: http://lkml.kernel.org/r/20170808080821.GA31730@bbox
Link: http://lkml.kernel.org/r/20170802000818.4760-7-namit@vmware.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Reported-by: Nadav Amit <namit@vmware.com>
Reported-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, tlb_flush_pending is used only for CONFIG_[NUMA_BALANCING|
COMPACTION] but upcoming patches to solve subtle TLB flush batching
problem will use it regardless of compaction/NUMA so this patch doesn't
remove the dependency.
[akpm@linux-foundation.org: remove more ifdefs from world's ugliest printk statement]
Link: http://lkml.kernel.org/r/20170802000818.4760-6-namit@vmware.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a preparatory patch for solving race problems caused by
TLB batch. For that, we will increase/decrease TLB flush pending count
of mm_struct whenever tlb_[gather|finish]_mmu is called.
Before making it simple, this patch separates architecture specific part
and rename it to arch_tlb_[gather|finish]_mmu and generic part just
calls it.
It shouldn't change any behavior.
Link: http://lkml.kernel.org/r/20170802000818.4760-5-namit@vmware.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While deferring TLB flushes is a good practice, the reverted patch
caused pending TLB flushes to be checked while the page-table lock is
not taken. As a result, in architectures with weak memory model (PPC),
Linux may miss a memory-barrier, miss the fact TLB flushes are pending,
and cause (in theory) a memory corruption.
Since the alternative of using smp_mb__after_unlock_lock() was
considered a bit open-coded, and the performance impact is expected to
be small, the previous patch is reverted.
This reverts b0943d61b8 ("mm: numa: defer TLB flush for THP migration
as long as possible").
Link: http://lkml.kernel.org/r/20170802000818.4760-4-namit@vmware.com
Signed-off-by: Nadav Amit <namit@vmware.com>
Suggested-by: Mel Gorman <mgorman@suse.de>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "fixes of TLB batching races", v6.
It turns out that Linux TLB batching mechanism suffers from various
races. Races that are caused due to batching during reclamation were
recently handled by Mel and this patch-set deals with others. The more
fundamental issue is that concurrent updates of the page-tables allow
for TLB flushes to be batched on one core, while another core changes
the page-tables. This other core may assume a PTE change does not
require a flush based on the updated PTE value, while it is unaware that
TLB flushes are still pending.
This behavior affects KSM (which may result in memory corruption) and
MADV_FREE and MADV_DONTNEED (which may result in incorrect behavior). A
proof-of-concept can easily produce the wrong behavior of MADV_DONTNEED.
Memory corruption in KSM is harder to produce in practice, but was
observed by hacking the kernel and adding a delay before flushing and
replacing the KSM page.
Finally, there is also one memory barrier missing, which may affect
architectures with weak memory model.
This patch (of 7):
Setting and clearing mm->tlb_flush_pending can be performed by multiple
threads, since mmap_sem may only be acquired for read in
task_numa_work(). If this happens, tlb_flush_pending might be cleared
while one of the threads still changes PTEs and batches TLB flushes.
This can lead to the same race between migration and
change_protection_range() that led to the introduction of
tlb_flush_pending. The result of this race was data corruption, which
means that this patch also addresses a theoretically possible data
corruption.
An actual data corruption was not observed, yet the race was was
confirmed by adding assertion to check tlb_flush_pending is not set by
two threads, adding artificial latency in change_protection_range() and
using sysctl to reduce kernel.numa_balancing_scan_delay_ms.
Link: http://lkml.kernel.org/r/20170802000818.4760-2-namit@vmware.com
Fixes: 2084140594 ("mm: fix TLB flush race between migration, and
change_protection_range")
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
huge_add_to_page_cache->add_to_page_cache implicitly unlocks the page
before returning in case of errors.
The error returned was -EEXIST by running UFFDIO_COPY on a non-hole
offset of a VM_SHARED hugetlbfs mapping. It was an userland bug that
triggered it and the kernel must cope with it returning -EEXIST from
ioctl(UFFDIO_COPY) as expected.
page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
kernel BUG at mm/filemap.c:964!
invalid opcode: 0000 [#1] SMP
CPU: 1 PID: 22582 Comm: qemu-system-x86 Not tainted 4.11.11-300.fc26.x86_64 #1
RIP: unlock_page+0x4a/0x50
Call Trace:
hugetlb_mcopy_atomic_pte+0xc0/0x320
mcopy_atomic+0x96f/0xbe0
userfaultfd_ioctl+0x218/0xe90
do_vfs_ioctl+0xa5/0x600
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x1a/0xa9
Link: http://lkml.kernel.org/r/20170802165145.22628-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The RDMA subsystem can generate several thousand of these messages per
second eventually leading to a kernel crash. Ratelimit these messages
to prevent this crash.
Doug said:
"I've been carrying a version of this for several kernel versions. I
don't remember when they started, but we have one (and only one) class
of machines: Dell PE R730xd, that generate these errors. When it
happens, without a rate limit, we get rcu timeouts and kernel oopses.
With the rate limit, we just get a lot of annoying kernel messages but
the machine continues on, recovers, and eventually the memory
operations all succeed"
And:
"> Well... why are all these EBUSY's occurring? It sounds inefficient
> (at least) but if it is expected, normal and unavoidable then
> perhaps we should just remove that message altogether?
I don't have an answer to that question. To be honest, I haven't
looked real hard. We never had this at all, then it started out of the
blue, but only on our Dell 730xd machines (and it hits all of them),
but no other classes or brands of machines. And we have our 730xd
machines loaded up with different brands and models of cards (for
instance one dedicated to mlx4 hardware, one for qib, one for mlx5, an
ocrdma/cxgb4 combo, etc), so the fact that it hit all of the machines
meant it wasn't tied to any particular brand/model of RDMA hardware.
To me, it always smelled of a hardware oddity specific to maybe the
CPUs or mainboard chipsets in these machines, so given that I'm not an
mm expert anyway, I never chased it down.
A few other relevant details: it showed up somewhere around 4.8/4.9 or
thereabouts. It never happened before, but the prinkt has been there
since the 3.18 days, so possibly the test to trigger this message was
changed, or something else in the allocator changed such that the
situation started happening on these machines?
And, like I said, it is specific to our 730xd machines (but they are
all identical, so that could mean it's something like their specific
ram configuration is causing the allocator to hit this on these
machine but not on other machines in the cluster, I don't want to say
it's necessarily the model of chipset or CPU, there are other bits of
identicalness between these machines)"
Link: http://lkml.kernel.org/r/499c0f6cc10d6eb829a67f2a4d75b4228a9b356e.1501695897.git.jtoppins@redhat.com
Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>
Reviewed-by: Doug Ledford <dledford@redhat.com>
Tested-by: Doug Ledford <dledford@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Tetsuo points out:
"Commit 385386cff4 ("mm: vmstat: move slab statistics from zone to
node counters") broke "Slab:" field of /proc/meminfo . It shows nearly
0kB"
In addition to /proc/meminfo, this problem also affects the slab
counters OOM/allocation failure info dumps, can cause early -ENOMEM from
overcommit protection, and miscalculate image size requirements during
suspend-to-disk.
This is because the patch in question switched the slab counters from
the zone level to the node level, but forgot to update the global
accessor functions to read the aggregate node data instead of the
aggregate zone data.
Use global_node_page_state() to access the global slab counters.
Fixes: 385386cff4 ("mm: vmstat: move slab statistics from zone to node counters")
Link: http://lkml.kernel.org/r/20170801134256.5400-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A while ago someone, and I cannot find the email just now, asked if we
could not implement the RECLAIM_FS inversion stuff with a 'fake' lock
like we use for other things like workqueues etc. I think this should
be possible which allows reducing the 'irq' states and will reduce the
amount of __bfs() lookups we do.
Removing the 1 IRQ state results in 4 less __bfs() walks per
dependency, improving lockdep performance. And by moving this
annotation out of the lockdep code it becomes easier for the mm people
to extend.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: iamjoonsoo.kim@lge.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit:
af2c1401e6 ("mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates")
added smp_mb__before_spinlock() to set_tlb_flush_pending(). I think we
can solve the same problem without this barrier.
If instead we mandate that mm_tlb_flush_pending() is used while
holding the PTL we're guaranteed to observe prior
set_tlb_flush_pending() instances.
For this to work we need to rework migrate_misplaced_transhuge_page()
a little and move the test up into do_huge_pmd_numa_page().
NOTE: this relies on flush_tlb_range() to guarantee:
(1) it ensures that prior page table updates are visible to the
page table walker and
(2) it ensures that subsequent memory accesses are only made
visible after the invalidation has completed
This is required for architectures that implement TRANSPARENT_HUGEPAGE
(arc, arm, arm64, mips, powerpc, s390, sparc, x86) or otherwise use
mm_tlb_flush_pending() in their page-table operations (arm, arm64,
x86).
This appears true for:
- arm (DSB ISB before and after),
- arm64 (DSB ISHST before, and DSB ISH after),
- powerpc (PTESYNC before and after),
- s390 and x86 TLB invalidate are serializing instructions
But I failed to understand the situation for:
- arc, mips, sparc
Now SPARC64 is a wee bit special in that flush_tlb_range() is a no-op
and it flushes the TLBs using arch_{enter,leave}_lazy_mmu_mode()
inside the PTL. It still needs to guarantee the PTL unlock happens
_after_ the invalidate completes.
Vineet, Ralf and Dave could you guys please have a look?
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Andre Wild reported the following warning:
WARNING: CPU: 2 PID: 1205 at kernel/cpu.c:240 lockdep_assert_cpus_held+0x4c/0x60
Modules linked in:
CPU: 2 PID: 1205 Comm: bash Not tainted 4.13.0-rc2-00022-gfd2b2c57ec20 #10
Hardware name: IBM 2964 N96 702 (z/VM 6.4.0)
task: 00000000701d8100 task.stack: 0000000073594000
Krnl PSW : 0704f00180000000 0000000000145e24 (lockdep_assert_cpus_held+0x4c/0x60)
...
Call Trace:
lockdep_assert_cpus_held+0x42/0x60)
stop_machine_cpuslocked+0x62/0xf0
build_all_zonelists+0x92/0x150
numa_zonelist_order_handler+0x102/0x150
proc_sys_call_handler.isra.12+0xda/0x118
proc_sys_write+0x34/0x48
__vfs_write+0x3c/0x178
vfs_write+0xbc/0x1a0
SyS_write+0x66/0xc0
system_call+0xc4/0x2b0
locks held by bash/1205:
#0: (sb_writers#4){.+.+.+}, at: vfs_write+0xa6/0x1a0
#1: (zl_order_mutex){+.+...}, at: numa_zonelist_order_handler+0x44/0x150
#2: (zonelists_mutex){+.+...}, at: numa_zonelist_order_handler+0xf4/0x150
Last Breaking-Event-Address:
lockdep_assert_cpus_held+0x48/0x60
This can be easily triggered with e.g.
echo n > /proc/sys/vm/numa_zonelist_order
In commit 3f906ba236 ("mm/memory-hotplug: switch locking to a percpu
rwsem") memory hotplug locking was changed to fix a potential deadlock.
This also switched the stop_machine() invocation within
build_all_zonelists() to stop_machine_cpuslocked() which now expects
that online cpus are locked when being called.
This assumption is not true if build_all_zonelists() is being called
from numa_zonelist_order_handler().
In order to fix this simply add a mem_hotplug_begin()/mem_hotplug_done()
pair to numa_zonelist_order_handler().
Link: http://lkml.kernel.org/r/20170726111738.38768-1-heiko.carstens@de.ibm.com
Fixes: 3f906ba236 ("mm/memory-hotplug: switch locking to a percpu rwsem")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Andre Wild <wild@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc-7 produces this warning:
mm/kasan/report.c: In function 'kasan_report':
mm/kasan/report.c:351:3: error: 'info.first_bad_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
print_shadow_for_address(info->first_bad_addr);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/kasan/report.c:360:27: note: 'info.first_bad_addr' was declared here
The code seems fine as we only print info.first_bad_addr when there is a
shadow, and we always initialize it in that case, but this is relatively
hard for gcc to figure out after the latest rework.
Adding an intialization to the most likely value together with the other
struct members shuts up that warning.
Fixes: b235b9808664 ("kasan: unify report headers")
Link: https://patchwork.kernel.org/patch/9641417/
Link: http://lkml.kernel.org/r/20170725152739.4176967-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Alexander Potapenko <glider@google.com>
Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When mremap is called with MREMAP_FIXED it unmaps memory at the
destination address without notifying userfaultfd monitor.
If the destination were registered with userfaultfd, the monitor has no
way to distinguish between the old and new ranges and to properly relate
the page faults that would occur in the destination region.
Fixes: 897ab3e0c4 ("userfaultfd: non-cooperative: add event for memory unmaps")
Link: http://lkml.kernel.org/r/1500276876-3350-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nadav Amit identified a theoritical race between page reclaim and
mprotect due to TLB flushes being batched outside of the PTL being held.
He described the race as follows:
CPU0 CPU1
---- ----
user accesses memory using RW PTE
[PTE now cached in TLB]
try_to_unmap_one()
==> ptep_get_and_clear()
==> set_tlb_ubc_flush_pending()
mprotect(addr, PROT_READ)
==> change_pte_range()
==> [ PTE non-present - no flush ]
user writes using cached RW PTE
...
try_to_unmap_flush()
The same type of race exists for reads when protecting for PROT_NONE and
also exists for operations that can leave an old TLB entry behind such
as munmap, mremap and madvise.
For some operations like mprotect, it's not necessarily a data integrity
issue but it is a correctness issue as there is a window where an
mprotect that limits access still allows access. For munmap, it's
potentially a data integrity issue although the race is massive as an
munmap, mmap and return to userspace must all complete between the
window when reclaim drops the PTL and flushes the TLB. However, it's
theoritically possible so handle this issue by flushing the mm if
reclaim is potentially currently batching TLB flushes.
Other instances where a flush is required for a present pte should be ok
as either the page lock is held preventing parallel reclaim or a page
reference count is elevated preventing a parallel free leading to
corruption. In the case of page_mkclean there isn't an obvious path
that userspace could take advantage of without using the operations that
are guarded by this patch. Other users such as gup as a race with
reclaim looks just at PTEs. huge page variants should be ok as they
don't race with reclaim. mincore only looks at PTEs. userfault also
should be ok as if a parallel reclaim takes place, it will either fault
the page back in or read some of the data before the flush occurs
triggering a fault.
Note that a variant of this patch was acked by Andy Lutomirski but this
was for the x86 parts on top of his PCID work which didn't make the 4.13
merge window as expected. His ack is dropped from this version and
there will be a follow-on patch on top of PCID that will include his
ack.
[akpm@linux-foundation.org: tweak comments]
[akpm@linux-foundation.org: fix spello]
Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.de
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: <stable@vger.kernel.org> [v4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 9a291a7c94 ("mm/hugetlb: report -EHWPOISON not -EFAULT when
FOLL_HWPOISON is specified") causes __get_user_pages to ignore certain
errors from follow_hugetlb_page. After such error, __get_user_pages
subsequently calls faultin_page on the same VMA and start address that
follow_hugetlb_page failed on instead of returning the error immediately
as it should.
In follow_hugetlb_page, when hugetlb_fault returns a value covered under
VM_FAULT_ERROR, follow_hugetlb_page returns it without setting nr_pages
to 0 as __get_user_pages expects in this case, which causes the
following to happen in __get_user_pages: the "while (nr_pages)" check
succeeds, we skip the "if (!vma..." check because we got a VMA the last
time around, we find no page with follow_page_mask, and we call
faultin_page, which calls hugetlb_fault for the second time.
This issue also slightly changes how __get_user_pages works. Before, it
only returned error if it had made no progress (i = 0). But now,
follow_hugetlb_page can clobber "i" with an error code since its new
return path doesn't check for progress. So if "i" is nonzero before a
failing call to follow_hugetlb_page, that indication of progress is lost
and __get_user_pages can return error even if some pages were
successfully pinned.
To fix this, change follow_hugetlb_page so that it updates nr_pages,
allowing __get_user_pages to fail immediately and restoring the "error
only if no progress" behavior to __get_user_pages.
Tested that __get_user_pages returns when expected on error from
hugetlb_fault in follow_hugetlb_page.
Fixes: 9a291a7c94 ("mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified")
Link: http://lkml.kernel.org/r/1500406795-58462-1-git-send-email-daniel.m.jordan@oracle.com
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: James Morse <james.morse@arm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: <stable@vger.kernel.org> [4.12.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Marcelo added this i_size based optimization with a patch in 2004
(commitid is from the linux-history tree):
commit 765dad09b4ac101a32d87af2bb793c3060497d3c
Author: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Date: Tue Sep 7 17:51:17 2004 -0700
small wait_on_page_writeback_range() optimization
filemap_fdatawait() calls wait_on_page_writeback_range() with -1
as "end" parameter. This is not needed since we know the EOF
from the inode. Use that instead.
There may be races here, particularly with clustered or network
filesystems. It also seems like a bit of a layering violation since
we're operating on an address_space here, not an inode.
Finally, it's also questionable whether this optimization really helps
on workloads that we care about. Should we be optimizing for writeback
vs. truncate races in a codepath where we expect to wait anyway? It
doesn't seem worth the risk.
Remove this optimization from the filemap_fdatawait codepaths. This
means that filemap_fdatawait becomes a trivial wrapper around
filemap_fdatawait_range.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Necessary now for gfs2_fsync and sync_file_range, but there will
eventually be other callers.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
We have this complex conditional copied to several places. Turn it into
a helper function.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
The other patches contain a lot of information, so adding this
information in a separate patch. It adds my copyright and a brief
explanation of how the bitmap allocator works. There is a minor typo as
well in the prior explanation so that is fixed.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The simple, and expensive, way to find a free area is to iterate over
the entire bitmap until an area is found that fits the allocation size
and alignment. This patch makes use of an iterate that find an area to
check by using the block level contig hints. It will only return an area
that can fit the size and alignment request. If the request can fit
inside a block, it returns the first_free bit to start checking from to
see if it can be fulfilled prior to the contig hint. The pcpu_alloc_area
check has a bound of a block size added in case it is wrong.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The largest free region will either be a block level contig hint or an
aggregate over the left_free and right_free areas of blocks. This is a
much smaller set of free areas that need to be checked than a full
traverse.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The bitmap allocator must keep metadata consistent. The easiest way is
to scan after every allocation for each affected block and the entire
chunk. This is rather expensive.
The free path can take advantage of current contig hints to prevent
scanning within the start and end block. If a scan is needed, it can
be done by scanning backwards from the start and forwards from the end
to identify the entire free area this can be combined with. The blocks
can then be updated by some basic checks rather than complete block
scans.
A chunk scan happens when the freed area makes a page free, a block
free, or spans across blocks. This is necessary as the contig hint at
this point could span across blocks. The check uses the minimum of page
size and the block size to allow for variable sized blocks. There is a
tradeoff here with not updating after every free. It is possible a
contig hint in one block can be merged with the contig hint in the next
block. This means the contig hint can be off by up to a page. However,
if the chunk's contig hint is contained in one block, the contig hint
will be accurate.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Metadata is kept per block to keep track of where the contig hints are.
Scanning can be avoided when the contig hints are not broken. In that
case, left and right contigs have to be managed manually.
This patch changes the allocation path hint updating to only scan when
contig hints are broken.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch makes the contig hint starting offset optimization from the
previous patch as honest as it can be. For both chunk and block starting
offsets, make sure it keeps the starting offset with the best alignment.
The block skip optimization is added in a later patch when the
pcpu_find_block_fit iterator is swapped in.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch adds chunk->contig_bits_start to keep track of the contig
hint's offset and the check to skip the chunk if it does not fit. If
the chunk's contig hint starting offset cannot satisfy an allocation,
the allocator assumes there is enough memory pressure in this chunk to
either use a different chunk or create a new one. This accepts a less
tight packing for a smoother latency curve.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch adds first_bit to keep track of the first free bit in the
bitmap. This hint helps prevent scanning of fully allocated blocks.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch introduces the bitmap metadata blocks and adds the skeleton
of the code that will be used to maintain these blocks. Each chunk's
bitmap is made up of full metadata blocks. These blocks maintain basic
metadata to help prevent scanning unnecssarily to update hints. Full
scanning methods are used for the skeleton and will be replaced in the
coming patches. A number of helper functions are added as well to do
conversion of pages to blocks and manage offsets. Comments will be
updated as the final version of each function is added.
There exists a relationship between PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE,
the region size, and unit_size. Every chunk's region (including offsets)
is page aligned at the beginning to preserve alignment. The end is
aligned to LCM(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE) to ensure that the end
can fit with the populated page map which is by page and every metadata
block is fully accounted for. The unit_size is already page aligned, but
must also be aligned with PCPU_BITMAP_BLOCK_SIZE to ensure full metadata
blocks.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The percpu memory allocator is experiencing scalability issues when
allocating and freeing large numbers of counters as in BPF.
Additionally, there is a corner case where iteration is triggered over
all chunks if the contig_hint is the right size, but wrong alignment.
This patch replaces the area map allocator with a basic bitmap allocator
implementation. Each subsequent patch will introduce new features and
replace full scanning functions with faster non-scanning options when
possible.
Implementation:
This patchset removes the area map allocator in favor of a bitmap
allocator backed by metadata blocks. The primary goal is to provide
consistency in performance and memory footprint with a focus on small
allocations (< 64 bytes). The bitmap removes the heavy memmove from the
freeing critical path and provides a consistent memory footprint. The
metadata blocks provide a bound on the amount of scanning required by
maintaining a set of hints.
In an effort to make freeing fast, the metadata is updated on the free
path if the new free area makes a page free, a block free, or spans
across blocks. This causes the chunk's contig hint to potentially be
smaller than what it could allocate by up to the smaller of a page or a
block. If the chunk's contig hint is contained within a block, a check
occurs and the hint is kept accurate. Metadata is always kept accurate
on allocation, so there will not be a situation where a chunk has a
later contig hint than available.
Evaluation:
I have primarily done testing against a simple workload of allocation of
1 million objects (2^20) of varying size. Deallocation was done by in
order, alternating, and in reverse. These numbers were collected after
rebasing ontop of a80099a152. I present the worst-case numbers here:
Area Map Allocator:
Object Size | Alloc Time (ms) | Free Time (ms)
----------------------------------------------
4B | 310 | 4770
16B | 557 | 1325
64B | 436 | 273
256B | 776 | 131
1024B | 3280 | 122
Bitmap Allocator:
Object Size | Alloc Time (ms) | Free Time (ms)
----------------------------------------------
4B | 490 | 70
16B | 515 | 75
64B | 610 | 80
256B | 950 | 100
1024B | 3520 | 200
This data demonstrates the inability for the area map allocator to
handle less than ideal situations. In the best case of reverse
deallocation, the area map allocator was able to perform within range
of the bitmap allocator. In the worst case situation, freeing took
nearly 5 seconds for 1 million 4-byte objects. The bitmap allocator
dramatically improves the consistency of the free path. The small
allocations performed nearly identical regardless of the freeing
pattern.
While it does add to the allocation latency, the allocation scenario
here is optimal for the area map allocator. The area map allocator runs
into trouble when it is allocating in chunks where the latter half is
full. It is difficult to replicate this, so I present a variant where
the pages are second half filled. Freeing was done sequentially. Below
are the numbers for this scenario:
Area Map Allocator:
Object Size | Alloc Time (ms) | Free Time (ms)
----------------------------------------------
4B | 4118 | 4892
16B | 1651 | 1163
64B | 598 | 285
256B | 771 | 158
1024B | 3034 | 160
Bitmap Allocator:
Object Size | Alloc Time (ms) | Free Time (ms)
----------------------------------------------
4B | 481 | 67
16B | 506 | 69
64B | 636 | 75
256B | 892 | 90
1024B | 3262 | 147
The data shows a parabolic curve of performance for the area map
allocator. This is due to the memmove operation being the dominant cost
with the lower object sizes as more objects are packed in a chunk and at
higher object sizes, the traversal of the chunk slots is the dominating
cost. The bitmap allocator suffers this problem as well. The above data
shows the inability to scale for the allocation path with the area map
allocator and that the bitmap allocator demonstrates consistent
performance in general.
The second problem of additional scanning can result in the area map
allocator completing in 52 minutes when trying to allocate 1 million
4-byte objects with 8-byte alignment. The same workload takes
approximately 16 seconds to complete for the bitmap allocator.
V2:
Fixed a bug in pcpu_alloc_first_chunk end_offset was setting the bitmap
using bytes instead of bits.
Added a comment to pcpu_cnt_pop_pages to explain bitmap_weight.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Nothing calls this wrapper anymore, so just remove it and rename the
old function to get rid of the double underscore prefix.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
The area map allocator only used a bitmap for the backing page state.
The new bitmap allocator will use bitmaps to manage the allocation
region in addition to this.
This patch generalizes the bitmap iterators so they can be reused with
the bitmap allocator.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch increases the minimum allocation size of percpu memory to
4-bytes. This change will help minimize the metadata overhead
associated with the bitmap allocator. The assumption is that most
allocations will be of objects or structs greater than 2 bytes with
integers or longs being used rather than shorts.
The first chunk regions are now aligned with the minimum allocation
size. The reserved region is expected to be set as a multiple of the
minimum allocation size. The static region is aligned up and the delta
is removed from the dynamic size. This works because the dynamic size is
increased to be page aligned. If the static size is not minimum
allocation size aligned, then there must be a gap that is added to the
dynamic size. The dynamic size will never be smaller than the set value.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
pcpu_nr_empty_pop_pages is used to ensure there are a handful of free
pages around to serve atomic allocations. A new field, nr_empty_pop_pages,
is added to the pcpu_chunk struct to keep track of the number of empty
pages. This field is needed as the number of empty populated pages is
globally tracked and deltas are used to update in the bitmap allocator.
Pages that contain a hidden area are not considered to be empty. This
new field is exposed in percpu_stats.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The populated bitmap represents the state of the pages the chunk serves.
Prior, the bitmap was marked completely used as the first chunk was
allocated and immutable. This is misleading because the first chunk may
not be completely filled. Additionally, with moving the base_addr up in
the previous patch, the population check no longer corresponds to what
was being checked.
This patch modifies the population map to be only the number of pages
the region serves and to make what it was checking correspond correctly
again. The change is to remove any misunderstanding between the size of
the populated bitmap and the actual size of it. The work function page
iterators now use nr_pages for the check rather than pcpu_unit_pages
because nr_populated is now chunk specific. Without this, the work
function would try to populate the remainder of these chunks despite it
not serving any more than nr_pages when nr_pages is set less than
pcpu_unit_pages.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The percpu address checks for the reserved and dynamic region chunks are
now specific to each region. The address checking logic can be combined
taking advantage of the global references to the dynamic and static
region chunks.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Originally, the first chunk was served by one or two chunks, each
given a region they are responsible for. Despite this, the arithmetic
was based off of the true base_addr of the chunk making it be overly
inclusive.
This patch moves the base_addr of chunks that are responsible for the
first chunk. The base_addr must remain page aligned to keep the
address alignment correct, so it is the beginning of the region served
page aligned down. start_offset holds where the region served begins
from this new base_addr.
The corresponding percpu address checks are modified to be more specific
as a result. The first chunk considers only the dynamic region and both
first chunk and reserved chunk checks ignore the static region. The
static region addresses should never be passed into the allocator. There
is no impact here besides distinguishing the first chunk and making the
checks specific.
The percpu pointer to physical address is left intact as addresses are
not given out in the non-allocated portion of percpu memory.
nr_pages is added to pcpu_chunk to keep track of the size of the entire
region served containing both start_offset and end_offset. This variable
will be used to manage the bitmap allocator.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There is no need to have the static chunk and dynamic chunk be named
separately as the allocations are sequential. This preemptively solves
the misnomer problem with the base_addrs being moved up in the following
patch. It also removes a ternary operation deciding the first chunk.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The area map allocator manages the first chunk area by hiding all but
the region it is responsible for serving in the area map. To align this
with the populated page bitmap, end_offset is introduced to keep track
of the delta to end page aligned. The area map is appended with the
page aligned end when necessary to be in line with how the bitmap
allocator requires the ending to be aligned with the LCM of PAGE_SIZE
and the size of each bitmap block. percpu_stats is updated to ignore
this region when present.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Create a common allocator for first chunk initialization,
pcpu_alloc_first_chunk. Comments for this function will be added in a
later patch once the bitmap allocator is added.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There is logic for setting variables in the static chunk init code that
could be consolidated with the dynamic chunk init code. This combines
this logic to setup for combining the allocation paths. reserved_size is
used as the conditional as a dynamic region will always exist.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Prior this variable was used to manage statistics when the first chunk
had a reserved region. The previous patch introduced start_offset to
keep track of the offset by value rather than boolean. Therefore,
has_reserved can be removed.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The reserved chunk arithmetic uses a global variable
pcpu_reserved_chunk_limit that is set in the first chunk init code to
hide a portion of the area map. The bitmap allocator to come will
eventually move the base_addr up and require both the reserved chunk
and static chunk to maintain this offset. pcpu_reserved_chunk_limit is
removed and start_offset is added.
The first chunk that is circulated and is pcpu_first_chunk serves the
dynamic region, the region following the reserved region. The reserved
chunk address check will temporarily use the first chunk to identify its
address range. A following patch will increase the base_addr and remove
this. If there is no reserved chunk, this will check the static region
and return false because those values should never be passed into the
allocator.
Lastly, when linking in the first chunk, make sure to count the right
free region for the number of empty populated pages.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The first chunk is handled as a special case as it is composed of the
static, reserved, and dynamic regions. The code handles each case
individually. The next several patches will merge these code paths and
lay the foundation for the bitmap allocator.
This patch modifies logic to enforce that a dynamic region exists and
changes the area map to account for that. This brings the logic closer
to the dynamic chunk's init logic.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently kasan_check_read/write() accept 'const void*', make them
accept 'const volatile void*'. This is required for instrumentation
of atomic operations and there is just no reason to not allow that.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/33e5ec275c1ee89299245b2ebbccd63709c6021f.1498140838.git.dvyukov@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
css_task_iter currently always walks all tasks. With the scheduled
cgroup v2 thread support, the iterator would need to handle multiple
types of iteration. As a preparation, add @flags to
css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag
is not specified, it walks all tasks as before. When asserted, the
iterator only walks the group leaders.
For now, the only user of the flag is cgroup v2 "cgroup.procs" file
which no longer needs to skip non-leader tasks in cgroup_procs_next().
Note that cgroup v1 "cgroup.procs" can't use the group leader walk as
v1 "cgroup.procs" doesn't mean "list all thread group leaders in the
cgroup" but "list all thread group id's with any threads in the
cgroup".
While at it, update cgroup_procs_show() to use task_pid_vnr() instead
of task_tgid_vnr(). As the iteration guarantees that the function
only sees group leaders, this doesn't change the output and will allow
sharing the function for thread iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Boot data (such as EFI related data) is not encrypted when the system is
booted because UEFI/BIOS does not run with SME active. In order to access
this data properly it needs to be mapped decrypted.
Update early_memremap() to provide an arch specific routine to modify the
pagetable protection attributes before they are applied to the new
mapping. This is used to remove the encryption mask for boot related data.
Update memremap() to provide an arch specific routine to determine if RAM
remapping is allowed. RAM remapping will cause an encrypted mapping to be
generated. By preventing RAM remapping, ioremap_cache() will be used
instead, which will provide a decrypted mapping of the boot related data.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/81fb6b4117a5df6b9f2eda342f81bbef4b23d2e5.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add early_memremap() support to be able to specify encrypted and
decrypted mappings with and without write-protection. The use of
write-protection is necessary when encrypting data "in place". The
write-protect attribute is considered cacheable for loads, but not
stores. This implies that the hardware will never give the core a
dirty line with this memtype.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/479b5832c30fae3efa7932e48f81794e86397229.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The header comment for percpu memory is a little hard to parse and is
not super clear about how the first chunk is managed. This adds a
little more clarity to the situation.
There is also quite a bit of tricky logic in the pcpu_build_alloc_info.
This adds a restructure of a comment to add a little more information.
Unfortunately, you will still have to piece together a handful of other
comments too, but should help direct you to the meaningful comments.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Percpu memory holds a minimum threshold of pages that are populated
in order to serve atomic percpu memory requests. This change makes it
easier to verify that there are a minimum number of populated pages
lying around.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This makes the debugfs output for percpu_stats a little easier
to read by changing the spacing of the output to be consistent.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Changes the use of a void buffer to an int buffer for clarity.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull ->s_options removal from Al Viro:
"Preparations for fsmount/fsopen stuff (coming next cycle). Everything
gets moved to explicit ->show_options(), killing ->s_options off +
some cosmetic bits around fs/namespace.c and friends. Basically, the
stuff needed to work with fsmount series with minimum of conflicts
with other work.
It's not strictly required for this merge window, but it would reduce
the PITA during the coming cycle, so it would be nice to have those
bits and pieces out of the way"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
isofs: Fix isofs_show_options()
VFS: Kill off s_options and helpers
orangefs: Implement show_options
9p: Implement show_options
isofs: Implement show_options
afs: Implement show_options
affs: Implement show_options
befs: Implement show_options
spufs: Implement show_options
bpf: Implement show_options
ramfs: Implement show_options
pstore: Implement show_options
omfs: Implement show_options
hugetlbfs: Implement show_options
VFS: Don't use save/replace_mount_options if not using generic_show_options
VFS: Provide empty name qstr
VFS: Make get_filesystem() return the affected filesystem
VFS: Clean up whitespace in fs/namespace.c and fs/super.c
Provide a function to create a NUL-terminated string from unterminated data
Jörn Engel noticed that the expand_upwards() function might not return
-ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and
if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE.
Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa
which all define TASK_SIZE as 0xffffffff, but since none of those have
an upwards-growing stack we currently have no actual issue.
Nevertheless let's fix this just in case any of the architectures with
an upward-growing stack (currently parisc, metag and partly ia64) define
TASK_SIZE similar.
Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box
Fixes: bd726c90b6 ("Allow stack to grow up to address space limit")
Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: Jörn Engel <joern@purestorage.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the writeback statistics code uses a percpu counters to hold
various statistics. Furthermore we have 2 families of functions - those
which disable local irq and those which doesn't and whose names begin
with double underscore. However, they both end up calling
__add_wb_stats which in turn calls percpu_counter_add_batch which is
already irq-safe.
Exploiting this fact allows to eliminated the __wb_* functions since
they don't add any further protection than we already have.
Furthermore, refactor the wb_* function to call __add_wb_stat directly
without the irq-disabling dance. This will likely result in better
runtime of code which deals with modifying the stat counters.
While at it also document why percpu_counter_add_batch is in fact
preempt and irq-safe since at least 3 people got confused.
Link: http://lkml.kernel.org/r/1498029937-27293-1-git-send-email-nborisov@suse.com
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page migration (for memory hotplug, soft_offline_page or mbind) needs to
allocate a new memory. This can trigger an oom killer if the target
memory is depleated. Although quite unlikely, still possible,
especially for the memory hotplug (offlining of memoery).
Up to now we didn't really have reasonable means to back off.
__GFP_NORETRY can fail just too easily and __GFP_THISNODE sticks to a
single node and that is not suitable for all callers.
But now that we have __GFP_RETRY_MAYFAIL we should use it. It is
preferable to fail the migration than disrupt the system by killing some
processes.
Link: http://lkml.kernel.org/r/20170623085345.11304-7-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that __GFP_RETRY_MAYFAIL has a reasonable semantic regardless of the
request size we can drop the hackish implementation for !costly orders.
__GFP_RETRY_MAYFAIL retries as long as the reclaim makes a forward
progress and backs of when we are out of memory for the requested size.
Therefore we do not need to enforce__GFP_NORETRY for !costly orders just
to silent the oom killer anymore.
Link: http://lkml.kernel.org/r/20170623085345.11304-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator. This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always
ignored for smaller sizes. This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.
Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success. This will work independent of the order and overrides the
default allocator behavior. Page allocator users have several levels of
guarantee vs. cost options (take GFP_KERNEL as an example)
- GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
attempt to free memory at all. The most light weight mode which even
doesn't kick the background reclaim. Should be used carefully because
it might deplete the memory and the next user might hit the more
aggressive reclaim
- GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
allocation without any attempt to free memory from the current
context but can wake kswapd to reclaim memory if the zone is below
the low watermark. Can be used from either atomic contexts or when
the request is a performance optimization and there is another
fallback for a slow path.
- (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
non sleeping allocation with an expensive fallback so it can access
some portion of memory reserves. Usually used from interrupt/bh
context with an expensive slow path fallback.
- GFP_KERNEL - both background and direct reclaim are allowed and the
_default_ page allocator behavior is used. That means that !costly
allocation requests are basically nofail but there is no guarantee of
that behavior so failures have to be checked properly by callers
(e.g. OOM killer victim is allowed to fail currently).
- GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
and all allocation requests fail early rather than cause disruptive
reclaim (one round of reclaim in this implementation). The OOM killer
is not invoked.
- GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
behavior and all allocation requests try really hard. The request
will fail if the reclaim cannot make any progress. The OOM killer
won't be triggered.
- GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
and all allocation requests will loop endlessly until they succeed.
This might be really dangerous especially for larger orders.
Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic. No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.
This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.
[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With gcc 4.1.2:
mm/memory.o: In function `create_huge_pmd':
memory.c:(.text+0x93e): undefined reference to `do_huge_pmd_anonymous_page'
Interestingly, create_huge_pmd() is emitted in the assembler output, but
never called.
Converting transparent_hugepage_enabled() from a macro to a static
inline function reduced the ability of the compiler to remove unused
code.
Fix this by marking create_huge_pmd() inline.
Fixes: 16981d7635 ("mm: improve readability of transparent_hugepage_enabled()")
Link: http://lkml.kernel.org/r/1499842660-10665-1-git-send-email-geert@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The helper function get_wild_bug_type() does not need to be in global
scope, so make it static.
Cleans up sparse warning:
"symbol 'get_wild_bug_type' was not declared. Should it be static?"
Link: http://lkml.kernel.org/r/20170622090049.10658-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They return positive value, that is, true, if non-zero value is found.
Rename them to reduce confusion.
Link: http://lkml.kernel.org/r/20170516012350.GA16015@js1304-desktop
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KASAN doesn't happen work with memory hotplug because hotplugged memory
doesn't have any shadow memory. So any access to hotplugged memory
would cause a crash on shadow check.
Use memory hotplug notifier to allocate and map shadow memory when the
hotplugged memory is going online and free shadow after the memory
offlined.
Link: http://lkml.kernel.org/r/20170601162338.23540-4-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For some unaligned memory accesses we have to check additional byte of
the shadow memory. Currently we load that byte speculatively to have
only single load + branch on the optimistic fast path.
However, this approach has some downsides:
- It's unaligned access, so this prevents porting KASAN on
architectures which doesn't support unaligned accesses.
- We have to map additional shadow page to prevent crash if speculative
load happens near the end of the mapped memory. This would
significantly complicate upcoming memory hotplug support.
I wasn't able to notice any performance degradation with this patch. So
these speculative loads is just a pain with no gain, let's remove them.
Link: http://lkml.kernel.org/r/20170601162338.23540-1-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is missing optimization in zero_p4d_populate() that can save some
memory when mapping zero shadow. Implement it like as others.
Link: http://lkml.kernel.org/r/1494829255-23946-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 40f9fb8cff ("mm/zsmalloc: support allocating obj with size of
ZS_MAX_ALLOC_SIZE") fixes a size calculation error that prevented
zsmalloc to allocate an object of the maximal size (ZS_MAX_ALLOC_SIZE).
I think however the fix is unneededly complicated.
This patch replaces the dynamic calculation of zs_size_classes at init
time by a compile time calculation that uses the DIV_ROUND_UP() macro
already used in get_size_class_index().
[akpm@linux-foundation.org: use min_t]
Link: http://lkml.kernel.org/r/20170630114859.1979-1-jmarchan@redhat.com
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Mahendran Ganesh <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrey reported a potential deadlock with the memory hotplug lock and
the cpu hotplug lock.
The reason is that memory hotplug takes the memory hotplug lock and then
calls stop_machine() which calls get_online_cpus(). That's the reverse
lock order to get_online_cpus(); get_online_mems(); in mm/slub_common.c
The problem has been there forever. The reason why this was never
reported is that the cpu hotplug locking had this homebrewn recursive
reader writer semaphore construct which due to the recursion evaded the
full lock dep coverage. The memory hotplug code copied that construct
verbatim and therefor has similar issues.
Three steps to fix this:
1) Convert the memory hotplug locking to a per cpu rwsem so the
potential issues get reported proper by lockdep.
2) Lock the online cpus in mem_hotplug_begin() before taking the memory
hotplug rwsem and use stop_machine_cpuslocked() in the page_alloc
code to avoid recursive locking.
3) The cpu hotpluck locking in #2 causes a recursive locking of the cpu
hotplug lock via __offline_pages() -> lru_add_drain_all(). Solve this
by invoking lru_add_drain_all_cpuslocked() instead.
Link: http://lkml.kernel.org/r/20170704093421.506836322@linutronix.de
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rework of the cpu hotplug locking unearthed potential deadlocks with
the memory hotplug locking code.
The solution for these is to rework the memory hotplug locking code as
well and take the cpu hotplug lock before the memory hotplug lock in
mem_hotplug_begin(), but this will cause a recursive locking of the cpu
hotplug lock when the memory hotplug code calls lru_add_drain_all().
Split out the inner workings of lru_add_drain_all() into
lru_add_drain_all_cpuslocked() so this function can be invoked from the
memory hotplug code with the cpu hotplug lock held.
Link: http://lkml.kernel.org/r/20170704093421.419329357@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use rlimit() helper instead of manually writing whole chain from current
task to rlim_cur.
Link: http://lkml.kernel.org/r/20170705172811.8027-1-k.opasiak@samsung.com
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
list_lru_count_node() iterates over all memcgs to get the total number of
entries on the node but it can race with memcg_drain_all_list_lrus(),
which migrates the entries from a dead cgroup to another. This can return
incorrect number of entries from list_lru_count_node().
Fix this by keeping track of entries per node and simply return it in
list_lru_count_node().
Link: http://lkml.kernel.org/r/1498707555-30525-1-git-send-email-stummala@codeaurora.org
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Alexander Polakov <apolyakov@beget.ru>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
expand_stack(vma) fails if address < stack_guard_gap even if there is no
vma->vm_prev. I don't think this makes sense, and we didn't do this
before the recent commit 1be7107fbe ("mm: larger stack guard gap,
between vmas").
We do not need a gap in this case, any address is fine as long as
security_mmap_addr() doesn't object.
This also simplifies the code, we know that address >= prev->vm_end and
thus underflow is not possible.
Link: http://lkml.kernel.org/r/20170628175258.GA24881@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 1be7107fbe ("mm: larger stack guard gap, between vmas") has
introduced a regression in some rust and Java environments which are
trying to implement their own stack guard page. They are punching a new
MAP_FIXED mapping inside the existing stack Vma.
This will confuse expand_{downwards,upwards} into thinking that the
stack expansion would in fact get us too close to an existing non-stack
vma which is a correct behavior wrt safety. It is a real regression on
the other hand.
Let's work around the problem by considering PROT_NONE mapping as a part
of the stack. This is a gros hack but overflowing to such a mapping
would trap anyway an we only can hope that usespace knows what it is
doing and handle it propely.
Fixes: 1be7107fbe ("mm: larger stack guard gap, between vmas")
Link: http://lkml.kernel.org/r/20170705182849.GA18027@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Debugged-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
presently pages in the balloon device have random value, and these pages
will be scanned by ksmd on the host. They usually cannot be merged.
Enqueue zero pages will resolve this problem.
Link: http://lkml.kernel.org/r/1498698637-26389-1-git-send-email-zhenwei.pi@youruncloud.com
Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The align_offset parameter is used by bitmap_find_next_zero_area_off()
to represent the offset of map's base from the previous alignment
boundary; the function ensures that the returned index, plus the
align_offset, honors the specified align_mask.
The logic introduced by commit b5be83e308 ("mm: cma: align to physical
address, not CMA region position") has the cma driver calculate the
offset to the *next* alignment boundary. In most cases, the base
alignment is greater than that specified when making allocations,
resulting in a zero offset whether we align up or down. In the example
given with the commit, the base alignment (8MB) was half the requested
alignment (16MB) so the math also happened to work since the offset is
8MB in both directions. However, when requesting allocations with an
alignment greater than twice that of the base, the returned index would
not be correctly aligned.
Also, the align_order arguments of cma_bitmap_aligned_mask() and
cma_bitmap_aligned_offset() should not be negative so the argument type
was made unsigned.
Fixes: b5be83e308 ("mm: cma: align to physical address, not CMA region position")
Link: http://lkml.kernel.org/r/20170628170742.2895-1-opendmb@gmail.com
Signed-off-by: Angus Clark <angus@angusclark.org>
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Angus Clark <angus@angusclark.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Shiraz Hashim <shashim@codeaurora.org>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__remove_zone() sets up up zone_type, but never uses it for anything.
This does not cause a warning, due to the (necessary) use of
-Wno-unused-but-set-variable. However, it's noise, so just delete it.
Link: http://lkml.kernel.org/r/20170624043421.24465-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_cpu_var() disables preemption and returns the per-CPU version of the
variable. Disabling preemption is useful to ensure atomic access to the
variable within the critical section.
In this case however, after the per-CPU version of the variable is
obtained the ->free_lock is acquired. For that reason it seems the raw
accessor could be used. It only seems that ->slots_ret should be
retested (because with disabled preemption this variable can not be set
to NULL otherwise).
This popped up during PREEMPT-RT testing because it tries to take
spinlocks in a preempt disabled section. In RT, spinlocks can sleep.
Link: http://lkml.kernel.org/r/20170623114755.2ebxdysacvgxzott@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since current_order starts as MAX_ORDER-1 and is then only decremented,
the second half of the loop condition seems superfluous. However, if
order is 0, we may decrement current_order past 0, making it UINT_MAX.
This is obviously too subtle ([1], [2]).
Since we need to add some comment anyway, change the two variables to
signed, making the counting-down for loop look more familiar, and
apparently also making gcc generate slightly smaller code.
[1] https://lkml.org/lkml/2016/6/20/493
[2] https://lkml.org/lkml/2017/6/19/345
[akpm@linux-foundation.org: fix up reject fixupping]
Link: http://lkml.kernel.org/r/20170621185529.2265-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reported-by: Hao Lee <haolee.swjtu@gmail.com>
Acked-by: Wei Yang <weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pagetypeinfo_showmixedcount_print is found to take a lot of time to
complete and it does this holding the zone lock and disabling
interrupts. In some cases it is found to take more than a second (On a
2.4GHz,8Gb RAM,arm64 cpu).
Avoid taking the zone lock similar to what is done by read_page_owner,
which means possibility of inaccurate results.
Link: http://lkml.kernel.org/r/1498045643-12257-1-git-send-email-vinmenon@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: zhongjiang <zhongjiang@huawei.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
new_page is yet another duplication of the migration callback which has
to handle hugetlb migration specially. We can safely use the generic
new_page_nodemask for the same purpose.
Please note that gigantic hugetlb pages do not need any special handling
because alloc_huge_page_nodemask will make sure to check pages in all
per node pools. The reason this was done previously was that
alloc_huge_page_node treated NO_NUMA_NODE and a specific node
differently and so alloc_huge_page_node(nid) would check on this
specific node.
Link: http://lkml.kernel.org/r/20170622193034.28972-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alloc_huge_page_nodemask tries to allocate from any numa node in the
allowed node mask starting from lower numa nodes. This might lead to
filling up those low NUMA nodes while others are not used. We can
reduce this risk by introducing a concept of the preferred node similar
to what we have in the regular page allocator. We will start allocating
from the preferred nid and then iterate over all allowed nodes in the
zonelist order until we try them all.
This is mimicing the page allocator logic except it operates on per-node
mempools. dequeue_huge_page_vma already does this so distill the
zonelist logic into a more generic dequeue_huge_page_nodemask and use it
in alloc_huge_page_nodemask.
This will allow us to use proper per numa distance fallback also for
alloc_huge_page_node which can use alloc_huge_page_nodemask now and we
can get rid of alloc_huge_page_node helper which doesn't have any user
anymore.
Link: http://lkml.kernel.org/r/20170622193034.28972-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm, hugetlb: allow proper node fallback dequeue".
While working on a hugetlb migration issue addressed in a separate
patchset[1] I have noticed that the hugetlb allocations from the
preallocated pool are quite subotimal.
[1] //lkml.kernel.org/r/20170608074553.22152-1-mhocko@kernel.org
There is no fallback mechanism implemented and no notion of preferred
node. I have tried to work around it but Vlastimil was right to push
back for a more robust solution. It seems that such a solution is to
reuse zonelist approach we use for the page alloctor.
This series has 3 patches. The first one tries to make hugetlb
allocation layers more clear. The second one implements the zonelist
hugetlb pool allocation and introduces a preferred node semantic which
is used by the migration callbacks. The last patch is a clean up.
This patch (of 3):
Hugetlb allocation path for fresh huge pages is unnecessarily complex
and it mixes different interfaces between layers.
__alloc_buddy_huge_page is the central place to perform a new
allocation. It checks for the hugetlb overcommit and then relies on
__hugetlb_alloc_buddy_huge_page to invoke the page allocator. This is
all good except that __alloc_buddy_huge_page pushes vma and address down
the callchain and so __hugetlb_alloc_buddy_huge_page has to deal with
two different allocation modes - one for memory policy and other node
specific (or to make it more obscure node non-specific) requests.
This just screams for a reorganization.
This patch pulls out all the vma specific handling up to
__alloc_buddy_huge_page_with_mpol where it belongs.
__alloc_buddy_huge_page will get nodemask argument and
__hugetlb_alloc_buddy_huge_page will become a trivial wrapper over the
page allocator.
In short:
__alloc_buddy_huge_page_with_mpol - memory policy handling
__alloc_buddy_huge_page - overcommit handling and accounting
__hugetlb_alloc_buddy_huge_page - page allocator layer
Also note that __hugetlb_alloc_buddy_huge_page and its cpuset retry loop
is not really needed because the page allocator already handles the
cpusets update.
Finally __hugetlb_alloc_buddy_huge_page had a special case for node
specific allocations (when no policy is applied and there is a node
given). This has relied on __GFP_THISNODE to not fallback to a different
node. alloc_huge_page_node is the only caller which relies on this
behavior so move the __GFP_THISNODE there.
Not only does this remove quite some code it also should make those
layers easier to follow and clear wrt responsibilities.
Link: http://lkml.kernel.org/r/20170622193034.28972-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During the debugging of the problem described in
https://lkml.org/lkml/2017/5/17/542 and fixed by Tetsuo Handa in
https://lkml.org/lkml/2017/5/19/383 , I've found that the existing debug
output is not really useful to understand issues related to the oom
reaper.
So, I assume, that adding some tracepoints might help with debugging of
similar issues.
Trace the following events:
1) a process is marked as an oom victim,
2) a process is added to the oom reaper list,
3) the oom reaper starts reaping process's mm,
4) the oom reaper finished reaping,
5) the oom reaper skips reaping.
How it works in practice? Below is an example which show how the problem
mentioned above can be found: one process is added twice to the
oom_reaper list:
$ cd /sys/kernel/debug/tracing
$ echo "oom:mark_victim" > set_event
$ echo "oom:wake_reaper" >> set_event
$ echo "oom:skip_task_reaping" >> set_event
$ echo "oom:start_task_reaping" >> set_event
$ echo "oom:finish_task_reaping" >> set_event
$ cat trace_pipe
allocate-502 [001] .... 91.836405: mark_victim: pid=502
allocate-502 [001] .N.. 91.837356: wake_reaper: pid=502
allocate-502 [000] .N.. 91.871149: wake_reaper: pid=502
oom_reaper-23 [000] .... 91.871177: start_task_reaping: pid=502
oom_reaper-23 [000] .N.. 91.879511: finish_task_reaping: pid=502
oom_reaper-23 [000] .... 91.879580: skip_task_reaping: pid=502
Link: http://lkml.kernel.org/r/20170530185231.GA13412@castle
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MADV_FREE is identical to MADV_DONTNEED from the point of view of uffd
monitor. The monitor has to stop handling #PF events in the range being
freed. We are reusing userfaultfd_remove callback along with the logic
required to re-get and re-validate the VMA which may change or disappear
because userfaultfd_remove releases mmap_sem.
Link: http://lkml.kernel.org/r/1497876311-18615-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The condition checking for THP straddling end of invalidated range is
wrong - it checks 'index' against 'end' but 'index' has been already
advanced to point to the end of THP and thus the condition can never be
true. As a result THP straddling 'end' has been fully invalidated.
Given the nature of invalidate_mapping_pages(), this could be only
performance issue. In fact, we are lucky the condition is wrong because
if it was ever true, we'd leave locked page behind.
Fix the condition checking for THP straddling 'end' and also properly
unlock the page. Also update the comment before the condition to
explain why we decide not to invalidate the page as it was not clear to
me and I had to ask Kirill.
Link: http://lkml.kernel.org/r/20170619124723.21656-1-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The hugetlb code has its own function to report human-readable sizes.
Convert it to use the shared string_get_size() function. This will lead
to a minor difference in user visible output (MiB/GiB instead of MB/GB),
but some would argue that's desirable anyway.
Link: http://lkml.kernel.org/r/20170606190350.GA20010@bombadil.infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alice has reported the following UBSAN splat:
UBSAN: Undefined behaviour in mm/memcontrol.c:661:17
signed integer overflow:
-2147483644 - 2147483525 cannot be represented in type 'long int'
CPU: 1 PID: 11758 Comm: mybibtex2filena Tainted: P O 4.9.25-gentoo #4
Hardware name: XXXXXX, BIOS YYYYYY
Call Trace:
dump_stack+0x59/0x87
ubsan_epilogue+0xe/0x40
handle_overflow+0xbb/0xf0
__ubsan_handle_sub_overflow+0x12/0x20
memcg_check_events.isra.36+0x223/0x360
mem_cgroup_commit_charge+0x55/0x140
wp_page_copy+0x34e/0xb80
do_wp_page+0x1e6/0x1300
handle_mm_fault+0x88b/0x1990
__do_page_fault+0x2de/0x8a0
do_page_fault+0x1a/0x20
error_code+0x67/0x6c
The reason is that we subtract two signed types. Let's fix this by
truly mimicing time_after and cast the result of the subtraction.
Link: http://lkml.kernel.org/r/20170616150057.GQ30580@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Alice Ferrazzi <alicef@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A few hugetlb allocators loop while calling the page allocator and can
potentially prevent rescheduling if the page allocator slowpath is not
utilized.
Conditionally schedule when large numbers of hugepages can be allocated.
Anshuman:
"Fixes a task which was getting hung while writing like 10000 hugepages
(16MB on POWER8) into /proc/sys/vm/nr_hugepages."
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1706091535300.66176@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 394e31d2ce ("mem-hotplug: alloc new page from a nearest
neighbor node when mem-offline") has duplicated a large part of
alloc_migrate_target with some hotplug specific special casing.
To be more precise it tried to enfore the allocation from a different
node than the original page. As a result the two function diverged in
their shared logic, e.g. the hugetlb allocation strategy.
Let's unify the two and express different NUMA requirements by the given
nodemask. new_node_page will simply exclude the node it doesn't care
about and alloc_migrate_target will use all the available nodes.
alloc_migrate_target will then learn to migrate hugetlb pages more
sanely and use preallocated pool when possible.
Please note that alloc_migrate_target used to call alloc_page resp.
alloc_pages_current so the memory policy of the current context which is
quite strange when we consider that it is used in the context of
alloc_contig_range which just tries to migrate pages which stand in the
way.
Link: http://lkml.kernel.org/r/20170608074553.22152-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
new_node_page will try to use the origin's next NUMA node as the
migration destination for hugetlb pages. If such a node doesn't have
any preallocated pool it falls back to __alloc_buddy_huge_page_no_mpol
to allocate a surplus page instead. This is quite subotpimal for any
configuration when hugetlb pages are no distributed to all NUMA nodes
evenly. Say we have a hotplugable node 4 and spare hugetlb pages are
node 0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:10000
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node2/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node3/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node4/hugepages/hugepages-2048kB/nr_hugepages:10000
/sys/devices/system/node/node5/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node6/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node7/hugepages/hugepages-2048kB/nr_hugepages:0
Now we consume the whole pool on node 4 and try to offline this node.
All the allocated pages should be moved to node0 which has enough
preallocated pages to hold them. With the current implementation
offlining very likely fails because hugetlb allocations during runtime
are much less reliable.
Fix this by reusing the nodemask which excludes migration source and try
to find a first node which has a page in the preallocated pool first and
fall back to __alloc_buddy_huge_page_no_mpol only when the whole pool is
consumed.
[akpm@linux-foundation.org: remove bogus arg from alloc_huge_page_nodemask() stub]
Link: http://lkml.kernel.org/r/20170608074553.22152-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
new_node_page tries to allocate the target page on a different NUMA node
than the source page. This makes sense in most cases during the hotplug
because we are likely to offline the whole numa node. But there are
cases where there are no other nodes to fallback (e.g. when offlining
parts of the only existing node) and we have to fallback to allocating
from the source node. The current code does that but it can be
simplified by checking the nmask and updating it before we even try to
allocate rather than special casing it.
This patch shouldn't introduce any functional change.
Link: http://lkml.kernel.org/r/20170608074553.22152-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
movable_node kernel parameter allows making hotpluggable NUMA nodes to
put all the hotplugable memory into movable zone which allows more or
less reliable memory hotremove. At least this is the case for the NUMA
nodes present during the boot (see find_zone_movable_pfns_for_nodes).
This is not the case for the memory hotplug, though.
echo online > /sys/devices/system/memory/memoryXYZ/state
will default to a kernel zone (usually ZONE_NORMAL) unless the
particular memblock is already in the movable zone range which is not
the case normally when onlining the memory from the udev rule context
for a freshly hotadded NUMA node. The only option currently is to have
a special udev rule to echo online_movable to all memblocks belonging to
such a node which is rather clumsy. Not to mention this is inconsistent
as well because what ended up in the movable zone during the boot will
end up in a kernel zone after hotremove & hotadd without special care.
It would be nice to reuse memblock_is_hotpluggable but the runtime
hotplug doesn't have that information available because the boot and
hotplug paths are not shared and it would be really non trivial to make
them use the same code path because the runtime hotplug doesn't play
with the memblock allocator at all.
Teach move_pfn_range that MMOP_ONLINE_KEEP can use the movable zone if
movable_node is enabled and the range doesn't overlap with the existing
normal zone. This should provide a reasonable default onlining
strategy.
Strictly speaking the semantic is not identical with the boot time
initialization because find_zone_movable_pfns_for_nodes covers only the
hotplugable range as described by the BIOS/FW. From my experience this
is usually a full node though (except for Node0 which is special and
never goes away completely). If this turns out to be a problem in the
real life we can tweak the code to store hotplug flag into memblocks but
let's keep this simple now.
Link: http://lkml.kernel.org/r/20170612111227.GI7476@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: <slaoub@gmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When migrating a transparent hugepage, migrate_misplaced_transhuge_page
guards itself against a concurrent fastgup of the page by checking that
the page count is equal to 2 before and after installing the new pmd.
If the page count changes, then the pmd is reverted back to the original
entry, however there is a small window where the new (possibly writable)
pmd is installed and the underlying page could be written by userspace.
Restoring the old pmd could therefore result in loss of data.
This patch fixes the problem by freezing the page count whilst updating
the page tables, which protects against a concurrent fastgup without the
need to restore the old pmd in the failure case (since the page count
can no longer change under our feet).
Link: http://lkml.kernel.org/r/1497349722-6731-4-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the user specifies too many hugepages or an invalid
default_hugepagesz the communication to the user is implicit in the
allocation message. This patch adds a warning when the desired page
count is not allocated and prints an error when the default_hugepagesz
is invalid on boot.
During boot hugepages will allocate until there is a fraction of the
hugepage size left. That is, we allocate until either the request is
satisfied or memory for the pages is exhausted. When memory for the
pages is exhausted, it will most likely lead to the system failing with
the OOM manager not finding enough (or anything) to kill (unless you're
using really big hugepages in the order of 100s of MB or in the GBs).
The user will most likely see the OOM messages much later in the boot
sequence than the implicitly stated message. Worse yet, you may even
get an OOM for each processor which causes many pages of OOMs on modern
systems. Although these messages will be printed earlier than the OOM
messages, at least giving the user errors and warnings will highlight
the configuration as an issue. I'm trying to point the user in the
right direction by providing a more robust statement of what is failing.
During the sysctl or echo command, the user can check the results much
easier than if the system hangs during boot and the scenario of having
nothing to OOM for kernel memory is highly unlikely.
Mike said:
"Before sending out this patch, I asked Liam off list why he was doing
it. Was it something he just thought would be useful? Or, was there
some type of user situation/need. He said that he had been called in
to assist on several occasions when a system OOMed during boot. In
almost all of these situations, the user had grossly misconfigured
huge pages.
DB users want to pre-allocate just the right amount of huge pages, but
sometimes they can be really off. In such situations, the huge page
init code just allocates as many huge pages as it can and reports the
number allocated. There is no indication that it quit allocating
because it ran out of memory. Of course, a user could compare the
number in the message to what they requested on the command line to
determine if they got all the huge pages they requested. The thought
was that it would be useful to at least flag this situation. That way,
the user might be able to better relate the huge page allocation
failure to the OOM.
I'm not sure if the e-mail discussion made it obvious that this is
something he has seen on several occasions.
I see Michal's point that this will only flag the situation where
someone configures huge pages very badly. And, a more extensive look
at the situation of misconfiguring huge pages might be in order. But,
this has happened on several occasions which led to the creation of
this patch"
[akpm@linux-foundation.org: reposition memfmt() to avoid forward declaration]
Link: http://lkml.kernel.org/r/20170603005413.10380-1-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: zhongjiang <zhongjiang@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While activating a CMA area we check to make sure that all the PFNs in
the range are inside the same zone. This is a requirement for
alloc_contig_range() to work. Any CMA area failing the check is
disabled for good. This happens silently right now making all future
cma_alloc() allocations failure inevitable.
Here we add an error message stating that the CMA area could not be
activated which makes it easier to explain any future cma_alloc()
failures on it. While in there, change the bail out goto label from
'err' to 'not_in_zone' which makes more sense.
Link: http://lkml.kernel.org/r/20170605023729.26303-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When ioremap a 67112960 bytes vm_area with the vmallocinfo:
[..]
0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc
0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap
we get the result:
0xf1000000-0xf5001000 67112960 devm_ioremap+0x38/0x7c phys=40000000 ioremap
For the align for ioremap must be less than '1 << IOREMAP_MAX_ORDER':
if (flags & VM_IOREMAP)
align = 1ul << clamp_t(int, get_count_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
So it makes idiot like me a litte puzzled why this was a jump the
vm_area from 0xec800000-0xecbe1000 to 0xf1000000-0xf5001000, and leaving
0xed000000-0xf1000000 as a big hole.
This patch is to show all of vm_area, including vmas which are freeing
but still in the vmap_area_list, to make it more clear about why we will
get 0xf1000000-0xf5001000 in the above case. And we will get a
vmallocinfo like:
[..]
0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc
0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap
[..]
0xece7c000-0xece7e000 8192 unpurged vm_area
0xece7e000-0xece83000 20480 vm_map_ram
0xf0099000-0xf00aa000 69632 vm_map_ram
after this patch.
Link: http://lkml.kernel.org/r/1496649682-20710-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: zijun_hu <zijun_hu@htc.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make @root exclusive in mem_cgroup_low; it is never considered low when
looked at directly and is not checked when traversing the tree. In
effect, @root is handled identically to how root_mem_cgroup was
previously handled by mem_cgroup_low.
If @root is not excluded from the checks, a cgroup underneath @root will
never be considered low during targeted reclaim of @root, e.g. due to
memory.current > memory.high, unless @root is misconfigured to have
memory.low > memory.high.
Excluding @root enables using memory.low to prioritize memory usage
between cgroups within a subtree of the hierarchy that is limited by
memory.high or memory.max, e.g. when ROOT owns @root's controls but
delegates the @root directory to a USER so that USER can create and
administer children of @root.
For example, given cgroup A with children B and C:
A
/ \
B C
and
1. A/memory.current > A/memory.high
2. A/B/memory.current < A/B/memory.low
3. A/C/memory.current >= A/C/memory.low
As 'A' is high, i.e. triggers reclaim from 'A', and 'B' is low, we
should reclaim from 'C' until 'A' is no longer high or until we can no
longer reclaim from 'C'. If 'A', i.e. @root, isn't excluded by
mem_cgroup_low when reclaming from 'A', then 'B' won't be considered low
and we will reclaim indiscriminately from both 'B' and 'C'.
Here is the test I used to confirm the bug and the patch.
20:00:55@sjchrist-vm ? ~ $ cat ~/.bin/memcg_low_test
#!/bin/bash
x62mb=$((62<<20))
x66mb=$((66<<20))
x94mb=$((94<<20))
x98mb=$((98<<20))
setup() {
set -e
if [[ -n $DEBUG ]]; then
set -x
fi
trap teardown EXIT HUP INT TERM
if [[ ! -e /mnt/1gb.swap ]]; then
sudo fallocate -l 1G /mnt/1gb.swap > /dev/null
sudo mkswap /mnt/1gb.swap > /dev/null
fi
if ! swapon --show=NAME | grep -q "/mnt/1gb.swap"; then
sudo swapon /mnt/1gb.swap
fi
if [[ ! -e /cgroup/cgroup.controllers ]]; then
sudo mount -t cgroup2 none /cgroup
fi
grep -q memory /cgroup/cgroup.controllers
sudo sh -c "echo '+memory' > /cgroup/cgroup.subtree_control"
sudo mkdir /cgroup/A && sudo chown $USER:$USER /cgroup/A
sudo sh -c "echo '+memory' > /cgroup/A/cgroup.subtree_control"
sudo sh -c "echo '96m' > /cgroup/A/memory.high"
mkdir /cgroup/A/0
mkdir /cgroup/A/1
echo 64m > /cgroup/A/0/memory.low
}
teardown() {
set +e
trap - EXIT HUP INT TERM
if [[ -z $1 ]]; then
printf "\n"
printf "%0.s*" {1..35}
printf "\nFAILED!\n\n"
tail /cgroup/A/**/memory.current
printf "%0.s*" {1..35}
printf "\n\n"
fi
ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill %
sleep 2
if [[ -e /cgroup/A/0 ]]; then
rmdir /cgroup/A/0
fi
if [[ -e /cgroup/A/1 ]]; then
rmdir /cgroup/A/1
fi
if [[ -e /cgroup/A ]]; then
sudo rmdir /cgroup/A
fi
}
stress_test() {
sudo sh -c "echo $$ > /cgroup/A/$1/cgroup.procs"
stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null &
sudo sh -c "echo $$ > /cgroup/A/$2/cgroup.procs"
stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null &
sudo sh -c "echo $$ > /cgroup/cgroup.procs"
sleep 1
# A/0 should be consuming more memory than A/1
[[ $(cat /cgroup/A/0/memory.current) -ge $(cat /cgroup/A/1/memory.current) ]]
# A/0 should be consuming ~64mb
[[ $(cat /cgroup/A/0/memory.current) -ge $x62mb ]] && [[ $(cat /cgroup/A/0/memory.current) -le $x66mb ]]
# A should cumulatively be consuming ~96mb
[[ $(cat /cgroup/A/memory.current) -ge $x94mb ]] && [[ $(cat /cgroup/A/memory.current) -le $x98mb ]]
# Stop the stressors
ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill %
}
teardown 1
setup
for ((i=1;i<=$1;i++)); do
printf "ITERATION $i of $1 - stress_test 0 1"
stress_test 0 1
printf "\x1b[2K\r"
printf "ITERATION $i of $1 - stress_test 1 0"
stress_test 1 0
printf "\x1b[2K\r"
printf "ITERATION $i of $1 - PASSED\n"
done
teardown 1
echo PASSED!
20:11:26@sjchrist-vm ? ~ $ memcg_low_test 10
Link: http://lkml.kernel.org/r/1496434412-21005-1-git-send-email-sean.j.christopherson@intel.com
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PR_SET_THP_DISABLE has a rather subtle semantic. It doesn't affect any
existing mapping because it only updated mm->def_flags which is a
template for new mappings.
The mappings created after prctl(PR_SET_THP_DISABLE) have VM_NOHUGEPAGE
flag set. This can be quite surprising for all those applications which
do not do prctl(); fork() & exec() and want to control their own THP
behavior.
Another usecase when the immediate semantic of the prctl might be useful
is a combination of pre- and post-copy migration of containers with
CRIU. In this case CRIU populates a part of a memory region with data
that was saved during the pre-copy stage. Afterwards, the region is
registered with userfaultfd and CRIU expects to get page faults for the
parts of the region that were not yet populated. However, khugepaged
collapses the pages and the expected page faults do not occur.
In more general case, the prctl(PR_SET_THP_DISABLE) could be used as a
temporary mechanism for enabling/disabling THP process wide.
Implementation wise, a new MMF_DISABLE_THP flag is added. This flag is
tested when decision whether to use huge pages is taken either during
page fault of at the time of THP collapse.
It should be noted, that the new implementation makes PR_SET_THP_DISABLE
master override to any per-VMA setting, which was not the case
previously.
Fixes: a0715cc226 ("mm, thp: add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE")
Link: http://lkml.kernel.org/r/1496415802-30944-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By default, vmpressure events are not pass-through, i.e. they propagate
up through the memcg hierarchy until an event notifier is found for any
threshold level.
This presents a difficulty when a thread waiting on a read(2) for a
vmpressure event cannot distinguish between local memory pressure and
memory pressure in a descendant memcg, especially when that thread may
not control the memcg hierarchy.
Consider a user-controlled child memcg with a smaller limit than a
top-level memcg controlled by the "Activity Manager" specified in
Documentation/cgroup-v1/memory.txt. It may register for memory pressure
notification for descendant memcgs to make a policy decision: oom kill a
low priority job, increase the limit, decrease other limits, etc. If it
registers for memory pressure notification on the top-level memcg, it
currently cannot distinguish between memory pressure in its own memcg or
a descendant memcg, which is user-controlled.
Conversely, if a user registers for memory pressure notification on
their own descendant memcg, the Activity Manager does not receive any
pressure notification for that child memcg hierarchy. Vmpressure events
are not received for ancestor memcgs if the memcg experiencing pressure
have notifiers registered, perhaps outside the knowledge of the thread
waiting on read(2) at the top level.
Both of these are consequences of vmpressure notification not being
pass-through.
This implements a pass-through behavior for vmpressure events. When
writing to control.event_control, vmpressure event handlers may
optionally specify a mode. There are two new modes:
- "hierarchy": always propagate memory pressure events up the hierarchy
regardless if descendant memcgs have their own notifiers registered,
and
- "local": only receive notifications when the memcg for which the
event is registered experiences memory pressure.
Of course, processes may register for one notification of "low,local",
for example, and another for "low".
If no mode is specified, the current behavior is maintained for
backwards compatibility.
See the change to Documentation/cgroup-v1/memory.txt for full
specification.
[dan.carpenter@oracle.com: free the same pointer we allocated]
Link: http://lkml.kernel.org/r/20170613191820.GA20003@elgon.mountain
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705311421320.8946@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dequeue_hwpoisoned_huge_page() is no longer used, so let's remove it.
Link: http://lkml.kernel.org/r/1496305019-5493-9-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently me_huge_page() relies on dequeue_hwpoisoned_huge_page() to
keep the error hugepage away from the system, which is OK but not good
enough because the hugepage still has a refcount and unpoison doesn't
work on the error hugepage (PageHWPoison flags are cleared but pages are
still leaked.) And there's "wasting health subpages" issue too. This
patch reworks on me_huge_page() to solve these issues.
For hugetlb file, recently we have truncating code so let's use it in
hugetlbfs specific ->error_remove_page().
For anonymous hugepage, it's helpful to dissolve the error page after
freeing it into free hugepage list. Migration entry and PageHWPoison in
the head page prevent the access to it.
TODO: dissolve_free_huge_page() can fail but we don't considered it yet.
It's not critical (and at least no worse that now) because in such case
the error hugepage just stays in free hugepage list without being
dissolved. By virtue of PageHWPoison in head page, it's never allocated
to processes.
[akpm@linux-foundation.org: fix unused var warnings]
Fixes: 23a003bfd2 ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1496305019-5493-8-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory_failure() is a big function and hard to maintain. Handling
hugetlb- and non-hugetlb- case in a single function is not good, so this
patch separates PageHuge() branch into a new function, which saves many
PageHuge() check.
Link: http://lkml.kernel.org/r/1496305019-5493-7-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now we have code to rescue most of healthy pages from a hwpoisoned
hugepage. So let's apply it to soft_offline_free_page too.
Link: http://lkml.kernel.org/r/1496305019-5493-6-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently hugepage migrated by soft-offline (i.e. due to correctable
memory errors) is contained as a hugepage, which means many non-error
pages in it are unreusable, i.e. wasted.
This patch solves this issue by dissolving source hugepages into buddy.
As done in previous patch, PageHWPoison is set only on a head page of
the error hugepage. Then in dissoliving we move the PageHWPoison flag
to the raw error page so that all healthy subpages return back to buddy.
[arnd@arndb.de: fix warnings: replace some macros with inline functions]
Link: http://lkml.kernel.org/r/20170609102544.2947326-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1496305019-5493-5-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We'd like to narrow down the error region in memory error on hugetlb
pages. However, currently we set PageHWPoison flags on all subpages in
the error hugepage and add # of subpages to num_hwpoison_pages, which
doesn't fit our purpose.
So this patch changes the behavior and we only set PageHWPoison on the
head page then increase num_hwpoison_pages only by 1. This is a
preparation for narrow-down part which comes in later patches.
Link: http://lkml.kernel.org/r/1496305019-5493-4-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We avoid calling __mod_node_page_state(NR_FILE_PAGES) for hugetlb page
now, but it's not enough because later code doesn't handle hugetlb
properly. Actually in our testing, WARN_ON_ONCE(PageDirty(page)) at the
end of this function fires for hugetlb, which makes no sense. So we
should return immediately for hugetlb pages.
Link: http://lkml.kernel.org/r/1496305019-5493-3-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: hwpoison: fixlet for hugetlb migration".
This patchset updates the hwpoison/hugetlb code to address 2 reported
issues.
One is madvise(MADV_HWPOISON) failure reported by Intel's lkp robot (see
http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop.) First
half was already fixed in mainline, and another half about hugetlb cases
are solved in this series.
Another issue is "narrow-down error affected region into a single 4kB
page instead of a whole hugetlb page" issue, which was tried by Anshuman
(http://lkml.kernel.org/r/20170420110627.12307-1-khandual@linux.vnet.ibm.com)
and I updated it to apply it more widely.
This patch (of 9):
We no longer use MIGRATE_ISOLATE to prevent reuse of hwpoison hugepages
as we did before. So current dequeue_huge_page_node() doesn't work as
intended because it still uses is_migrate_isolate_page() for this check.
This patch fixes it with PageHWPoison flag.
Link: http://lkml.kernel.org/r/1496305019-5493-2-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
is_first_page() is only called from the macro VM_BUG_ON_PAGE() which is
only compiled in as a runtime check when CONFIG_DEBUG_VM is set,
otherwise is checked at compile time and not actually compiled in.
Fixes the following warning, found with Clang:
mm/zsmalloc.c:472:12: warning: function 'is_first_page' is not needed and will not be emitted [-Wunneeded-internal-declaration]
static int is_first_page(struct page *page)
^
Link: http://lkml.kernel.org/r/20170524053859.29059-1-nick.desaulniers@gmail.com
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The NULL check at line 1226: if (!pgdat), implies that pointer pgdat
might be NULL.
rollback_node_hotadd() dereferences this pointer. Add NULL check to
avoid a potential NULL pointer dereference.
Addresses-Coverity-ID: 1369133
Link: http://lkml.kernel.org/r/20170530212436.GA6195@embeddedgus
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The purpose of the code that commit 623762517e ("revert 'mm: vmscan:
do not swap anon pages just because free+file is low'") reintroduces is
to prefer swapping anonymous memory rather than trashing the file lru.
If the anonymous inactive lru for the set of eligible zones is
considered low, however, or the length of the list for the given reclaim
priority does not allow for effective anonymous-only reclaiming, then
avoid forcing SCAN_ANON. Forcing SCAN_ANON will end up thrashing the
small list and leave unreclaimed memory on the file lrus.
If the inactive list is insufficient, fallback to balanced reclaim so
the file lru doesn't remain untouched.
[akpm@linux-foundation.org: fix build]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705011432220.137835@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The preferred strategy to define debugfs attributes is to use the
DEFINE_DEBUGFS_ATTRIBUTE() macro and to use debugfs_create_file_unsafe().
Link: http://lkml.kernel.org/r/20170528145948.32127-1-y.pronenko@gmail.com
Signed-off-by: Yevgen Pronenko <y.pronenko@gmail.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 3bc48f96cf ("mm, page_alloc: split smallest stolen page
in fallback") we pick the smallest (but sufficient) page of all that
have been stolen from a pageblock of different migratetype. However,
there are cases when we decide not to steal the whole pageblock.
Practically in the current implementation it means that we are trying to
fallback for a MIGRATE_MOVABLE allocation of order X, go through the
freelists from MAX_ORDER-1 down to X, and find free page of order Y. If
Y is less than pageblock_order / 2, we decide not to steal all pages
from the pageblock. When Y > X, it means we are potentially splitting a
larger page than we need, as there might be other pages of order Z,
where X <= Z < Y. Since Y is already too small to steal whole
pageblock, picking smallest available Z will result in the same decision
and we avoid splitting a higher-order page in a MIGRATE_UNMOVABLE or
MIGRATE_RECLAIMABLE pageblock.
This patch therefore changes the fallback algorithm so that in the
situation described above, we switch the fallback search strategy to go
from order X upwards to find the smallest suitable fallback. In theory
there shouldn't be a downside of this change wrt fragmentation.
This has been tested with mmtests' stress-highalloc performing
GFP_KERNEL order-4 allocations, here is the relevant extfrag tracepoint
statistics:
4.12.0-rc2 4.12.0-rc2
1-kernel4 2-kernel4
Page alloc extfrag event 25640976 69680977
Extfrag fragmenting 25621086 69661364
Extfrag fragmenting for unmovable 74409 73204
Extfrag fragmenting unmovable placed with movable 69003 67684
Extfrag fragmenting unmovable placed with reclaim. 5406 5520
Extfrag fragmenting for reclaimable 6398 8467
Extfrag fragmenting reclaimable placed with movable 869 884
Extfrag fragmenting reclaimable placed with unmov. 5529 7583
Extfrag fragmenting for movable 25540279 69579693
Since we force movable allocations to steal the smallest available page
(which we then practially always split), we steal less per fallback, so
the number of fallbacks increases and steals potentially happen from
different pageblocks. This is however not an issue for movable pages
that can be compacted.
Importantly, the "unmovable placed with movable" statistics is lower,
which is the result of less fragmentation in the unmovable pageblocks.
The effect on reclaimable allocation is a bit unclear.
Link: http://lkml.kernel.org/r/20170529093947.22618-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For fast flash disk, async IO could introduce overhead because of
context switch. block-mq now supports IO poll, which improves
performance and latency a lot. swapin is a good place to use this
technique, because the task is waiting for the swapin page to continue
execution.
In my virtual machine, directly read 4k data from a NVMe with iopoll is
about 60% better than that without poll. With iopoll support in swapin
patch, my microbenchmark (a task does random memory write) is about
10%~25% faster. CPU utilization increases a lot though, 2x and even 3x
CPU utilization. This will depend on disk speed.
While iopoll in swapin isn't intended for all usage cases, it's a win
for latency sensistive workloads with high speed swap disk. block layer
has knob to control poll in runtime. If poll isn't enabled in block
layer, there should be no noticeable change in swapin.
I got a chance to run the same test in a NVMe with DRAM as the media.
In simple fio IO test, blkpoll boosts 50% performance in single thread
test and ~20% in 8 threads test. So this is the base line. In above
swap test, blkpoll boosts ~27% performance in single thread test.
blkpoll uses 2x CPU time though.
If we enable hybid polling, the performance gain has very slight drop
but CPU time is only 50% worse than that without blkpoll. Also we can
adjust parameter of hybid poll, with it, the CPU time penality is
reduced further. In 8 threads test, blkpoll doesn't help though. The
performance is similar to that without blkpoll, but cpu utilization is
similar too. There is lock contention in swap path. The cpu time
spending on blkpoll isn't high. So overall, blkpoll swapin isn't worse
than that without it.
The swapin readahead might read several pages in in the same time and
form a big IO request. Since the IO will take longer time, it doesn't
make sense to do poll, so the patch only does iopoll for single page
swapin.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/070c3c3e40b711e7b1390002c991e86a-b5408f0@7511894063d3764ff01ea8111f5a004d7dd700ed078797c204a24e620ddb965c
Signed-off-by: Shaohua Li <shli@fb.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ARM updates from Russell King:
- add support for ftrace-with-registers, which is needed for kgraft and
other ftrace tools
- support for mremap() for the sigpage/vDSO so that checkpoint/restore
can work
- add timestamps to each line of the register dump output
- remove the unused KTHREAD_SIZE from nommu
- align the ARM bitops APIs with the generic API (using unsigned long
pointers rather than void pointers)
- make the configuration of userspace Thumb support an expert option so
that we can default it on, and avoid some hard to debug userspace
crashes
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8684/1: NOMMU: Remove unused KTHREAD_SIZE definition
ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO
ARM: 8679/1: bitops: Align prototypes to generic API
ARM: 8678/1: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS
ARM: make configuration of userspace Thumb support an expert option
ARM: 8673/1: Fix __show_regs output timestamps
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Merge tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling updates from Jeff Layton:
"This pile represents the bulk of the writeback error handling fixes
that I have for this cycle. Some of the earlier patches in this pile
may look trivial but they are prerequisites for later patches in the
series.
The aim of this set is to improve how we track and report writeback
errors to userland. Most applications that care about data integrity
will periodically call fsync/fdatasync/msync to ensure that their
writes have made it to the backing store.
For a very long time, we have tracked writeback errors using two flags
in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
writeback error occurs (via mapping_set_error) and are cleared as a
side-effect of filemap_check_errors (as you noted yesterday). This
model really sucks for userland.
Only the first task to call fsync (or msync or fdatasync) will see the
error. Any subsequent task calling fsync on a file will get back 0
(unless another writeback error occurs in the interim). If I have
several tasks writing to a file and calling fsync to ensure that their
writes got stored, then I need to have them coordinate with one
another. That's difficult enough, but in a world of containerized
setups that coordination may even not be possible.
But wait...it gets worse!
The calls to filemap_check_errors can be buried pretty far down in the
call stack, and there are internal callers of filemap_write_and_wait
and the like that also end up clearing those errors. Many of those
callers ignore the error return from that function or return it to
userland at nonsensical times (e.g. truncate() or stat()). If I get
back -EIO on a truncate, there is no reason to think that it was
because some previous writeback failed, and a subsequent fsync() will
(incorrectly) return 0.
This pile aims to do three things:
1) ensure that when a writeback error occurs that that error will be
reported to userland on a subsequent fsync/fdatasync/msync call,
regardless of what internal callers are doing
2) report writeback errors on all file descriptions that were open at
the time that the error occurred. This is a user-visible change,
but I think most applications are written to assume this behavior
anyway. Those that aren't are unlikely to be hurt by it.
3) document what filesystems should do when there is a writeback
error. Today, there is very little consistency between them, and a
lot of cargo-cult copying. We need to make it very clear what
filesystems should do in this situation.
To achieve this, the set adds a new data type (errseq_t) and then
builds new writeback error tracking infrastructure around that. Once
all of that is in place, we change the filesystems to use the new
infrastructure for reporting wb errors to userland.
Note that this is just the initial foray into cleaning up this mess.
There is a lot of work remaining here:
1) convert the rest of the filesystems in a similar fashion. Once the
initial set is in, then I think most other fs' will be fairly
simple to convert. Hopefully most of those can in via individual
filesystem trees.
2) convert internal waiters on writeback to use errseq_t for
detecting errors instead of relying on the AS_* flags. I have some
draft patches for this for ext4, but they are not quite ready for
prime time yet.
This was a discussion topic this year at LSF/MM too. If you're
interested in the gory details, LWN has some good articles about this:
https://lwn.net/Articles/718734/https://lwn.net/Articles/724307/"
* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
btrfs: minimal conversion to errseq_t writeback error reporting on fsync
xfs: minimal conversion to errseq_t writeback error reporting
ext4: use errseq_t based error handling for reporting data writeback errors
fs: convert __generic_file_fsync to use errseq_t based reporting
block: convert to errseq_t based writeback error tracking
dax: set errors in mapping when writeback fails
Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
fs: new infrastructure for writeback error handling and reporting
lib: add errseq_t type and infrastructure for handling it
mm: don't TestClearPageError in __filemap_fdatawait_range
mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
jbd2: don't clear and reset errors after waiting on writeback
buffer: set errors in mapping at the time that the error occurs
fs: check for writeback errors after syncing out buffers in generic_file_fsync
buffer: use mapping_set_error instead of setting the flag
mm: fix mapping_set_error call in me_pagecache_dirty
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Merge tag 'for-linus-v4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling fixes from Jeff Layton:
"The main rationale for all of these changes is to tighten up writeback
error reporting to userland. There are many ways now that writeback
errors can be lost, such that fsync/fdatasync/msync return 0 when
writeback actually failed.
This pile contains a small set of cleanups and writeback error
handling fixes that I was able to break off from the main pile (#2).
Two of the patches in this pile are trivial. The exceptions are the
patch to fix up error handling in write_one_page, and the patch to
make JFS pay attention to write_one_page errors"
* tag 'for-linus-v4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
fs: remove call_fsync helper function
mm: clean up error handling in write_one_page
JFS: do not ignore return code from write_one_page()
mm: drop "wait" parameter from write_one_page()
Highlights include:
- Support for STRICT_KERNEL_RWX on 64-bit server CPUs.
- Platform support for FSP2 (476fpe) board
- Enable ZONE_DEVICE on 64-bit server CPUs.
- Generic & powerpc spin loop primitives to optimise busy waiting
- Convert VDSO update function to use new update_vsyscall() interface
- Optimisations to hypercall/syscall/context-switch paths
- Improvements to the CPU idle code on Power8 and Power9.
As well as many other fixes and improvements.
Thanks to:
Akshay Adiga, Andrew Donnellan, Andrew Jeffery, Anshuman Khandual, Anton
Blanchard, Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe
Lombard, Colin Ian King, Dan Carpenter, Gautham R. Shenoy, Hari Bathini, Ian
Munsie, Ivan Mikhaylov, Javier Martinez Canillas, Madhavan Srinivasan,
Masahiro Yamada, Matt Brown, Michael Neuling, Michal Suchanek, Murilo
Opsfelder Araujo, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul
Mackerras, Pavel Machek, Russell Currey, Santosh Sivaraj, Stephen Rothwell,
Thiago Jung Bauermann, Yang Li.
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Merge tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights include:
- Support for STRICT_KERNEL_RWX on 64-bit server CPUs.
- Platform support for FSP2 (476fpe) board
- Enable ZONE_DEVICE on 64-bit server CPUs.
- Generic & powerpc spin loop primitives to optimise busy waiting
- Convert VDSO update function to use new update_vsyscall() interface
- Optimisations to hypercall/syscall/context-switch paths
- Improvements to the CPU idle code on Power8 and Power9.
As well as many other fixes and improvements.
Thanks to: Akshay Adiga, Andrew Donnellan, Andrew Jeffery, Anshuman
Khandual, Anton Blanchard, Balbir Singh, Benjamin Herrenschmidt,
Christophe Leroy, Christophe Lombard, Colin Ian King, Dan Carpenter,
Gautham R. Shenoy, Hari Bathini, Ian Munsie, Ivan Mikhaylov, Javier
Martinez Canillas, Madhavan Srinivasan, Masahiro Yamada, Matt Brown,
Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Naveen N.
Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pavel Machek,
Russell Currey, Santosh Sivaraj, Stephen Rothwell, Thiago Jung
Bauermann, Yang Li"
* tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits)
powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs
powerpc/mm/radix: Implement STRICT_RWX/mark_rodata_ro() for Radix
powerpc/mm/hash: Implement mark_rodata_ro() for hash
powerpc/vmlinux.lds: Align __init_begin to 16M
powerpc/lib/code-patching: Use alternate map for patch_instruction()
powerpc/xmon: Add patch_instruction() support for xmon
powerpc/kprobes/optprobes: Use patch_instruction()
powerpc/kprobes: Move kprobes over to patch_instruction()
powerpc/mm/radix: Fix execute permissions for interrupt_vectors
powerpc/pseries: Fix passing of pp0 in updatepp() and updateboltedpp()
powerpc/64s: Blacklist rtas entry/exit from kprobes
powerpc/64s: Blacklist functions invoked on a trap
powerpc/64s: Un-blacklist system_call() from kprobes
powerpc/64s: Move system_call() symbol to just after setting MSR_EE
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes
powerpc/64s: Convert .L__replay_interrupt_return to a local label
powerpc64/elfv1: Only dereference function descriptor for non-text symbols
cxl: Export library to support IBM XSL
powerpc/dts: Use #include "..." to include local DT
powerpc/perf/hv-24x7: Aggregate result elements on POWER9 SMT8
...
movable_node_is_enabled is defined in memblock proper while it is
initialized from the memory hotplug proper. This is quite messy and it
makes a dependency between the two so move movable_node along with the
helper functions to memory_hotplug.
To make it more entertaining the kernel parameter is ignored unless
CONFIG_HAVE_MEMBLOCK_NODE_MAP=y because we do not have the node
information for each memblock otherwise. So let's warn when the option
is disabled.
Link: http://lkml.kernel.org/r/20170529114141.536-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 20b2f52b73 ("numa: add CONFIG_MOVABLE_NODE for
movable-dedicated node") has introduced CONFIG_MOVABLE_NODE without a
good explanation on why it is actually useful.
It makes a lot of sense to make movable node semantic opt in but we
already have that because the feature has to be explicitly enabled on
the kernel command line. A config option on top only makes the
configuration space larger without a good reason. It also adds an
additional ifdefery that pollutes the code.
Just drop the config option and make it de-facto always enabled. This
shouldn't introduce any change to the semantic.
Link: http://lkml.kernel.org/r/20170529114141.536-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "remove CONFIG_MOVABLE_NODE".
I am continuing to clean up the memory hotplug code and
CONFIG_MOVABLE_NODE seems dubious at best. The following two patches
simply removes the flag and make it de-facto always enabled.
The current semantic of the config option is twofold 1) it automatically
binds hotplugable nodes to have memory in zone_movable by default when
movable_node is enabled 2) forbids memory hotplug to online all the
memory as movable when !CONFIG_MOVABLE_NODE.
The later restriction is quite dubious because there is no clear cut of
how much normal memory do we need for a reasonable system operation. A
single memory block which is sufficient to allow further movable onlines
is far from sufficient (e.g a node with >2GB and memblocks 128MB will
fill up this zone with struct pages leaving nothing for other
allocations). Removing the config option will not only reduce the
configuration space it also removes quite some code.
The semantic of the movable_node command line parameter is preserved.
The first patch removes the restriction mentioned above and the second
one simply removes all the CONFIG_MOVABLE_NODE related stuff. The last
patch moves movable_node flag handling to memory_hotplug proper where it
belongs.
[1] http://lkml.kernel.org/r/20170524122411.25212-1-mhocko@kernel.org
This patch (of 3):
Commit 74d42d8fe1 ("memory_hotplug: ensure every online node has
NORMAL memory") has introduced a restriction that every numa node has to
have at least some memory in !movable zones before a first movable
memory can be onlined if !CONFIG_MOVABLE_NODE.
Likewise can_offline_normal checks the amount of normal memory in
!movable zones and it disallows to offline memory if there is no normal
memory left with a justification that "memory-management acts bad when
we have nodes which is online but don't have any normal memory".
While it is true that not having _any_ memory for kernel allocations on
a NUMA node is far from great and such a node would be quite subotimal
because all kernel allocations will have to fallback to another NUMA
node but there is no reason to disallow such a configuration in
principle.
Besides that there is not really a big difference to have one memblock
for ZONE_NORMAL available or none. With 128MB size memblocks the system
might trash on the kernel allocations requests anyway. It is really
hard to draw a line on how much normal memory is really sufficient so we
have to rely on administrator to configure system sanely therefore drop
the artificial restriction and remove can_offline_normal and
can_online_high_movable altogether.
Link: http://lkml.kernel.org/r/20170529114141.536-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Josef's redesign of the balancing between slab caches and the page cache
requires slab cache statistics at the lruvec level.
Link: http://lkml.kernel.org/r/20170530181724.27197-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lruvecs are at the intersection of the NUMA node and memcg, which is the
scope for most paging activity.
Introduce a convenient accounting infrastructure that maintains
statistics per node, per memcg, and the lruvec itself.
Then convert over accounting sites for statistics that are already
tracked in both nodes and memcgs and can be easily switched.
[hannes@cmpxchg.org: fix crash in the new cgroup stat keeping code]
Link: http://lkml.kernel.org/r/20170531171450.GA10481@cmpxchg.org
[hannes@cmpxchg.org: don't track uncharged pages at all
Link: http://lkml.kernel.org/r/20170605175254.GA8547@cmpxchg.org
[hannes@cmpxchg.org: add missing free_percpu()]
Link: http://lkml.kernel.org/r/20170605175354.GB8547@cmpxchg.org
[linux@roeck-us.net: hexagon: fix build error caused by include file order]
Link: http://lkml.kernel.org/r/20170617153721.GA4382@roeck-us.net
Link: http://lkml.kernel.org/r/20170530181724.27197-6-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kmem-specific functions do the same thing. Switch and drop.
Link: http://lkml.kernel.org/r/20170530181724.27197-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the slab counters are moved from the zone to the node level we
can drop the private memcg node stats and use the official ones.
Link: http://lkml.kernel.org/r/20170530181724.27197-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: per-lruvec slab stats"
Josef is working on a new approach to balancing slab caches and the page
cache. For this to work, he needs slab cache statistics on the lruvec
level. These patches implement that by adding infrastructure that
allows updating and reading generic VM stat items per lruvec, then
switches some existing VM accounting sites, including the slab
accounting ones, to this new cgroup-aware API.
I'll follow up with more patches on this, because there is actually
substantial simplification that can be done to the memory controller
when we replace private memcg accounting with making the existing VM
accounting sites cgroup-aware. But this is enough for Josef to base his
slab reclaim work on, so here goes.
This patch (of 5):
To re-implement slab cache vs. page cache balancing, we'll need the
slab counters at the lruvec level, which, ever since lru reclaim was
moved from the zone to the node, is the intersection of the node, not
the zone, and the memcg.
We could retain the per-zone counters for when the page allocator dumps
its memory information on failures, and have counters on both levels -
which on all but NUMA node 0 is usually redundant. But let's keep it
simple for now and just move them. If anybody complains we can restore
the per-zone counters.
[hannes@cmpxchg.org: fix oops]
Link: http://lkml.kernel.org/r/20170605183511.GA8915@cmpxchg.org
Link: http://lkml.kernel.org/r/20170530181724.27197-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the specification of a data structure by a pointer dereference
as the parameter for the operator "sizeof" to make the corresponding
size determination a bit safer according to the Linux coding style
convention.
Link: http://lkml.kernel.org/r/19f9da22-092b-f867-bdf6-f4dbad7ccf1f@users.sourceforge.net
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To reduce the lock contention of swap_info_struct->lock when freeing
swap entry. The freed swap entries will be collected in a per-CPU
buffer firstly, and be really freed later in batch. During the batch
freeing, if the consecutive swap entries in the per-CPU buffer belongs
to same swap device, the swap_info_struct->lock needs to be
acquired/released only once, so that the lock contention could be
reduced greatly. But if there are multiple swap devices, it is possible
that the lock may be unnecessarily released/acquired because the swap
entries belong to the same swap device are non-consecutive in the
per-CPU buffer.
To solve the issue, the per-CPU buffer is sorted according to the swap
device before freeing the swap entries.
With the patch, the memory (some swapped out) free time reduced 11.6%
(from 2.65s to 2.35s) in the vm-scalability swap-w-rand test case with
16 processes. The test is done on a Xeon E5 v3 system. The swap device
used is a RAM simulated PMEM (persistent memory) device. To test
swapping, the test case creates 16 processes, which allocate and write
to the anonymous pages until the RAM and part of the swap device is used
up, finally the memory (some swapped out) is freed before exit.
[akpm@linux-foundation.org: tweak comment]
Link: http://lkml.kernel.org/r/20170525005916.25249-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Show count of oom killer invocations in /proc/vmstat and count of
processes killed in memory cgroup in knob "memory.events" (in
memory.oom_control for v1 cgroup).
Also describe difference between "oom" and "oom_kill" in memory cgroup
documentation. Currently oom in memory cgroup kills tasks iff shortage
has happened inside page fault.
These counters helps in monitoring oom kills - for now the only way is
grepping for magic words in kernel log.
[akpm@linux-foundation.org: fix for mem_cgroup_count_vm_event() rename]
[akpm@linux-foundation.org: fix comment, per Konstantin]
Link: http://lkml.kernel.org/r/149570810989.203600.9492483715840752937.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Roman Guschin <guroan@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Track the following reclaim counters for every memory cgroup: PGREFILL,
PGSCAN, PGSTEAL, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE and PGLAZYFREED.
These values are exposed using the memory.stats interface of cgroup v2.
The meaning of each value is the same as for global counters, available
using /proc/vmstat.
Also, for consistency, rename mem_cgroup_count_vm_event() to
count_memcg_event_mm().
Link: http://lkml.kernel.org/r/1494530183-30808-1-git-send-email-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kmemleak requires that vmalloc'ed objects have a minimum reference count
of 2: one in the corresponding vm_struct object and the other owned by
the vmalloc() caller. There are cases, however, where the original
vmalloc() returned pointer is lost and, instead, a pointer to vm_struct
is stored (see free_thread_stack()). Kmemleak currently reports such
objects as leaks.
This patch adds support for treating any surplus references to an object
as additional references to a specified object. It introduces the
kmemleak_vmalloc() API function which takes a vm_struct pointer and sets
its surplus reference passing to the actual vmalloc() returned pointer.
The __vmalloc_node_range() calling site has been modified accordingly.
Link: http://lkml.kernel.org/r/1495726937-23557-4-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scan_block() updates the number of references (pointers) to objects,
adding them to the gray_list when object->min_count is reached. The
patch factors out this functionality into a separate update_refs()
function.
Link: http://lkml.kernel.org/r/1495726937-23557-3-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the kmemleak_object.flags type to unsigned int and moves the
early_log.min_count (int) near early_log.op_type (int) to slightly
reduce the size of these structures on 64-bit architectures.
Link: http://lkml.kernel.org/r/1495726937-23557-2-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Two wrappers of __alloc_pages_nodemask() are checking
task->mems_allowed_seq themselves to retry allocation that has raced
with a cpuset update.
This has been shown to be ineffective in preventing premature OOM's
which can happen in __alloc_pages_slowpath() long before it returns back
to the wrappers to detect the race at that level.
Previous patches have made __alloc_pages_slowpath() more robust, so we
can now simply remove the seqlock checking in the wrappers to prevent
further wrong impression that it can actually help.
Link: http://lkml.kernel.org/r/20170517081140.30654-7-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit c0ff7453bb ("cpuset,mm: fix no node to alloc memory when
changing cpuset's mems") has introduced a two-step protocol when
rebinding task's mempolicy due to cpuset update, in order to avoid a
parallel allocation seeing an empty effective nodemask and failing.
Later, commit cc9a6c8776 ("cpuset: mm: reduce large amounts of memory
barrier related damage v3") introduced a seqlock protection and removed
the synchronization point between the two update steps. At that point
(or perhaps later), the two-step rebinding became unnecessary.
Currently it only makes sure that the update first adds new nodes in
step 1 and then removes nodes in step 2. Without memory barriers the
effects are questionable, and even then this cannot prevent a parallel
zonelist iteration checking the nodemask at each step to observe all
nodes as unusable for allocation. We now fully rely on the seqlock to
prevent premature OOMs and allocation failures.
We can thus remove the two-step update parts and simplify the code.
Link: http://lkml.kernel.org/r/20170517081140.30654-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The main allocator function __alloc_pages_nodemask() takes a zonelist
pointer as one of its parameters. All of its callers directly or
indirectly obtain the zonelist via node_zonelist() using a preferred
node id and gfp_mask. We can make the code a bit simpler by doing the
zonelist lookup in __alloc_pages_nodemask(), passing it a preferred node
id instead (gfp_mask is already another parameter).
There are some code size benefits thanks to removal of inlined
node_zonelist():
bloat-o-meter add/remove: 2/2 grow/shrink: 4/36 up/down: 399/-1351 (-952)
This will also make things simpler if we proceed with converting cpusets
to zonelists.
Link: http://lkml.kernel.org/r/20170517081140.30654-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The task->il_next variable stores the next allocation node id for task's
MPOL_INTERLEAVE policy. mpol_rebind_nodemask() updates interleave and
bind mempolicies due to changing cpuset mems. Currently it also tries
to make sure that current->il_next is valid within the updated nodemask.
This is bogus, because 1) we are updating potentially any task's
mempolicy, not just current, and 2) we might be updating a per-vma
mempolicy, not task one.
The interleave_nodes() function that uses il_next can cope fine with the
value not being within the currently allowed nodes, so this hasn't
manifested as an actual issue.
We can remove the need for updating il_next completely by changing it to
il_prev and store the node id of the previous interleave allocation
instead of the next id. Then interleave_nodes() can calculate the next
id using the current nodemask and also store it as il_prev, except when
querying the next node via do_get_mempolicy().
Link: http://lkml.kernel.org/r/20170517081140.30654-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I would like to stress that this patchset aims to fix issues and cleanup
the code *within the existing documented semantics*, i.e. patch 1
ignores mempolicy restrictions if the set of allowed nodes has no
intersection with set of nodes allowed by cpuset. I believe discussing
potential changes of the semantics can be better done once we have a
baseline with no known bugs of the current semantics.
I've recently summarized the cpuset/mempolicy issues in a LSF/MM
proposal [1] and the discussion itself [2]. I've been trying to rewrite
the handling as proposed, with the idea that changing semantics to make
all mempolicies static wrt cpuset updates (and discarding the relative
and default modes) can be tried on top, as there's a high risk of being
rejected/reverted because somebody might still care about the removed
modes.
However I haven't yet figured out how to properly:
1) make mempolicies swappable instead of rebinding in place. I thought
mbind() already works that way and uses refcounting to avoid
use-after-free of the old policy by a parallel allocation, but turns
out true refcounting is only done for shared (shmem) mempolicies, and
the actual protection for mbind() comes from mmap_sem. Extending the
refcounting means more overhead in allocator hot path. Also swapping
whole mempolicies means that we have to allocate the new ones, which
can fail, and reverting of the partially done work also means
allocating (note that mbind() doesn't care and will just leave part
of the range updated and part not updated when returning -ENOMEM...).
2) make cpuset's task->mems_allowed also swappable (after converting it
from nodemask to zonelist, which is the easy part) for mostly the
same reasons.
The good news is that while trying to do the above, I've at least
figured out how to hopefully close the remaining premature OOM's, and do
a buch of cleanups on top, removing quite some of the code that was also
supposed to prevent the cpuset update races, but doesn't work anymore
nowadays. This should fix the most pressing concerns with this topic
and give us a better baseline before either proceeding with the original
proposal, or pushing a change of semantics that removes the problem 1)
above. I'd be then fine with trying to change the semantic first and
rewrite later.
Patchset has been tested with the LTP cpuset01 stress test.
[1] https://lkml.kernel.org/r/4c44a589-5fd8-08d0-892c-e893bb525b71@suse.cz
[2] https://lwn.net/Articles/717797/
[3] https://marc.info/?l=linux-mm&m=149191957922828&w=2
This patch (of 6):
Commit e47483bca2 ("mm, page_alloc: fix premature OOM when racing with
cpuset mems update") has fixed known recent regressions found by LTP's
cpuset01 testcase. I have however found that by modifying the testcase
to use per-vma mempolicies via bind(2) instead of per-task mempolicies
via set_mempolicy(2), the premature OOM still happens and the issue is
much older.
The root of the problem is that the cpuset's mems_allowed and
mempolicy's nodemask can temporarily have no intersection, thus
get_page_from_freelist() cannot find any usable zone. The current
semantic for empty intersection is to ignore mempolicy's nodemask and
honour cpuset restrictions. This is checked in node_zonelist(), but the
racy update can happen after we already passed the check. Such races
should be protected by the seqlock task->mems_allowed_seq, but it
doesn't work here, because 1) mpol_rebind_mm() does not happen under
seqlock for write, and doing so would lead to deadlock, as it takes
mmap_sem for write, while the allocation can have mmap_sem for read when
it's taking the seqlock for read. And 2) the seqlock cookie of callers
of node_zonelist() (alloc_pages_vma() and alloc_pages_current()) is
different than the one of __alloc_pages_slowpath(), so there's still a
potential race window.
This patch fixes the issue by having __alloc_pages_slowpath() check for
empty intersection of cpuset and ac->nodemask before OOM or allocation
failure. If it's indeed empty, the nodemask is ignored and allocation
retried, which mimics node_zonelist(). This works fine, because almost
all callers of __alloc_pages_nodemask are obtaining the nodemask via
node_zonelist(). The only exception is new_node_page() from hotplug,
where the potential violation of nodemask isn't an issue, as there's
already a fallback allocation attempt without any nodemask. If there's
a future caller that needs to have its specific nodemask honoured over
task's cpuset restrictions, we'll have to e.g. add a gfp flag for that.
Link: http://lkml.kernel.org/r/20170517081140.30654-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using set_pte_at() does not do the right thing when putting down
HWPOISON swap entries for hugepages on architectures that support
contiguous ptes.
Fix this problem by using set_huge_swap_pte_at() which was introduced to
fix exactly this problem.
Link: http://lkml.kernel.org/r/20170522133604.11392-7-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_huge_pte_at(), an architecture callback to populate hugepage ptes,
does not provide the range of virtual memory that is targeted. This
leads to ambiguity when dealing with swap entries on architectures that
support hugepages consisting of contiguous ptes.
Fix the problem by introducing an overridable helper that is called when
populating the page tables with swap entries. The size of the targeted
region is provided to the helper to help determine the number of entries
to be updated.
Provide a default implementation that maintains the current behaviour.
[punit.agrawal@arm.com: v4]
Link: http://lkml.kernel.org/r/20170524115409.31309-8-punit.agrawal@arm.com
[punit.agrawal@arm.com: add an empty definition for set_huge_swap_pte_at()]
Link: http://lkml.kernel.org/r/20170525171331.31469-1-punit.agrawal@arm.com
Link: http://lkml.kernel.org/r/20170522133604.11392-6-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When unmapping a hugepage range, huge_pte_clear() is used to clear the
page table entries that are marked as not present. huge_pte_clear()
internally just ends up calling pte_clear() which does not correctly
deal with hugepages consisting of contiguous page table entries.
Add a size argument to address this issue and allow architectures to
override huge_pte_clear() by wrapping it in a #ifndef block.
Update s390 implementation with the size parameter as well.
Note that the change only affects huge_pte_clear() - the other generic
hugetlb functions don't need any change.
Link: http://lkml.kernel.org/r/20170522162555.4313-1-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A poisoned or migrated hugepage is stored as a swap entry in the page
tables. On architectures that support hugepages consisting of
contiguous page table entries (such as on arm64) this leads to ambiguity
in determining the page table entry to return in huge_pte_offset() when
a poisoned entry is encountered.
Let's remove the ambiguity by adding a size parameter to convey
additional information about the requested address. Also fixup the
definition/usage of huge_pte_offset() throughout the tree.
Link: http://lkml.kernel.org/r/20170522133604.11392-4-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com> (odd fixer:METAG ARCHITECTURE)
Cc: Ralf Baechle <ralf@linux-mips.org> (supporter:MIPS)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When speculatively taking references to a hugepage using
page_cache_add_speculative() in gup_huge_pmd(), it is assumed that the
page returned by pmd_page() is the head page. Although normally true,
this assumption doesn't hold when the hugepage comprises of successive
page table entries such as when using contiguous bit on arm64 at PTE or
PMD levels.
This can be addressed by ensuring that the page passed to
page_cache_add_speculative() is the real head or by de-referencing the
head page within the function.
We take the first approach to keep the usage pattern aligned with
page_cache_get_speculative() where users already pass the appropriate
page, i.e., the de-referenced head.
Apply the same logic to fix gup_huge_[pud|pgd]() as well.
[punit.agrawal@arm.com: fix arm64 ltp failure]
Link: http://lkml.kernel.org/r/20170619170145.25577-5-punit.agrawal@arm.com
Link: http://lkml.kernel.org/r/20170522133604.11392-3-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When operating on hugepages with DEBUG_VM enabled, the GUP code checks
the compound head for each tail page prior to calling
page_cache_add_speculative. This is broken, because on the fast-GUP
path (where we don't hold any page table locks) we can be racing with a
concurrent invocation of split_huge_page_to_list.
split_huge_page_to_list deals with this race by using page_ref_freeze to
freeze the page and force concurrent GUPs to fail whilst the component
pages are modified. This modification includes clearing the
compound_head field for the tail pages, so checking this prior to a
successful call to page_cache_add_speculative can lead to false
positives: In fact, page_cache_add_speculative *already* has this check
once the page refcount has been successfully updated, so we can simply
remove the broken calls to VM_BUG_ON_PAGE.
Link: http://lkml.kernel.org/r/20170522133604.11392-2-punit.agrawal@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pte_offset_map_lock() finds and takes ptl, and returns pte. But some
callers return without unlocking the ptl when pte == NULL, which seems
weird.
Git history said that !pte check in change_pte_range() was introduced in
commit 1ad9f620c3 ("mm: numa: recheck for transhuge pages under lock
during protection changes") and still remains after commit 175ad4f1e7
("mm: mprotect: use pmd_trans_unstable instead of taking the pmd_lock")
which partially reverts 1ad9f620c3. So I think that it's just dead
code.
Many other caller of pte_offset_map_lock() never check NULL return, so
let's do likewise.
Link: http://lkml.kernel.org/r/1495089737-1292-1-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The functions are not used in some configurations. Adding the attribute
fixes the following warnings when building with clang:
mm/page_alloc.c:409:19: error: function 'bad_range' is not needed and
will not be emitted [-Werror,-Wunneeded-internal-declaration]
mm/page_alloc.c:1106:30: error: unused function 'meminit_pfn_in_nid'
[-Werror,-Wunused-function]
Link: http://lkml.kernel.org/r/20170518182030.165633-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This moves the #ifdef in C code to a Kconfig dependency. Also we move
the gigantic_page_supported() function to be arch specific.
This allows architectures to conditionally enable runtime allocation of
gigantic huge page. Architectures like ppc64 supports different
gigantic huge page size (16G and 1G) based on the translation mode
selected. This provides an opportunity for ppc64 to enable runtime
allocation only w.r.t 1G hugepage.
No functional change in this patch.
Link: http://lkml.kernel.org/r/1494995292-4443-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow hash tables to scale with memory but at slower pace, when
HASH_ADAPT is provided every time memory quadruples the sizes of hash
tables will only double instead of quadrupling as well. This algorithm
starts working only when memory size reaches a certain point, currently
set to 64G.
This is example of dentry hash table size, before and after four various
memory configurations:
MEMORY SCALE HASH_SIZE
old new old new
8G 13 13 8M 8M
16G 13 13 16M 16M
32G 13 13 32M 32M
64G 13 13 64M 64M
128G 13 14 128M 64M
256G 13 14 256M 128M
512G 13 15 512M 128M
1024G 13 15 1024M 256M
2048G 13 16 2048M 256M
4096G 13 16 4096M 512M
8192G 13 17 8192M 512M
16384G 13 17 16384M 1024M
32768G 13 18 32768M 1024M
65536G 13 18 65536M 2048M
The effect of this change on runtime is undetectable as filesystem
growth is not proportional to machine memory size as is currently
assumed. The change effects only large memory machine. Additional
tuning might be needed, but that can be done by the clients of the
kmem_cache_create interface, not the generic cache allocator itself.
The adaptive hashing is disabled on 32 bit systems to avoid confusion of
whether base should be different for smaller systems, and to avoid
overflows.
[mhocko@suse.com: drop HASH_ADAPT]
Link: http://lkml.kernel.org/r/20170509094607.GG6481@dhcp22.suse.cz
[pasha.tatashin@oracle.com: UL -> ULL fix]
Link: http://lkml.kernel.org/r/1495300013-653283-2-git-send-email-pasha.tatashin@oracle.com
[pasha.tatashin@oracle.com: disable adaptive hash on 32 bit systems]
Link: http://lkml.kernel.org/r/1495469329-755807-2-git-send-email-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/1488432825-92126-5-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Babu Moger <babu.moger@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new flag HASH_ZERO which when provided grantees that the hash
table that is returned by alloc_large_system_hash() is zeroed. In most
cases that is what is needed by the caller. Use page level allocator's
__GFP_ZERO flags to zero the memory. It is using memset() which is
efficient method to zero memory and is optimized for most platforms.
Link: http://lkml.kernel.org/r/1488432825-92126-3-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Architectures like ppc64 supports hugepage size that is not mapped to
any of of the page table levels. Instead they add an alternate page
table entry format called hugepage directory (hugepd). hugepd indicates
that the page table entry maps to a set of hugetlb pages. Add support
for this in generic follow_page_mask code. We already support this
format in the generic gup code.
The default implementation prints warning and returns NULL. We will add
ppc64 support in later patches
Link: http://lkml.kernel.org/r/1494926612-23928-7-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ppc64 supports pgd hugetlb entries. Add code to handle hugetlb pgd
entries to follow_page_mask so that ppc64 can switch to it to handle
hugetlbe entries.
Link: http://lkml.kernel.org/r/1494926612-23928-5-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We will be using this later from the ppc64 code. Change the return type
to bool.
Link: http://lkml.kernel.org/r/1494926612-23928-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Makes code reading easy. No functional changes in this patch. In a
followup patch, we will be updating the follow_page_mask to handle
hugetlb hugepd format so that archs like ppc64 can switch to the generic
version. This split helps in doing that nicely.
Link: http://lkml.kernel.org/r/1494926612-23928-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "HugeTLB migration support for PPC64", v2.
This patch (of 9):
The right interface to use to set a hugetlb pte entry is set_huge_pte_at.
Use that instead of set_pte_at.
Link: http://lkml.kernel.org/r/1494926612-23928-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Though migrating gigantic HugeTLB pages does not sound much like real
world use case, they can be affected by memory errors. Hence migration
at the PGD level HugeTLB pages should be supported just to enable soft
and hard offline use cases.
While allocating the new gigantic HugeTLB page, it should not matter
whether new page comes from the same node or not. There would be very
few gigantic pages on the system afterall, we should not be bothered
about node locality when trying to save a big page from crashing.
This change renames dequeu_huge_page_node() function as dequeue_huge
_page_node_exact() preserving it's original functionality. Now the new
dequeue_huge_page_node() function scans through all available online nodes
to allocate a huge page for the NUMA_NO_NODE case and just falls back
calling dequeu_huge_page_node_exact() for all other cases.
[arnd@arndb.de: make hstate_is_gigantic() inline]
Link: http://lkml.kernel.org/r/20170522124748.3911296-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170516100509.20122-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zone_for_memory doesn't have any user anymore as well as the whole zone
shifting infrastructure so drop them all.
This shouldn't introduce any functional changes.
Link: http://lkml.kernel.org/r/20170515085827.16474-15-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tobias has reported following section mismatches introduced by "mm,
memory_hotplug: do not associate hotadded memory to zones until online".
WARNING: mm/built-in.o(.text+0x5a1c2): Section mismatch in reference from the function move_pfn_range_to_zone() to the function .meminit.text:memmap_init_zone()
The function move_pfn_range_to_zone() references
the function __meminit memmap_init_zone().
This is often because move_pfn_range_to_zone lacks a __meminit
annotation or the annotation of memmap_init_zone is wrong.
WARNING: mm/built-in.o(.text+0x5a25b): Section mismatch in reference from the function move_pfn_range_to_zone() to the function .meminit.text:init_currently_empty_zone()
The function move_pfn_range_to_zone() references
the function __meminit init_currently_empty_zone().
This is often because move_pfn_range_to_zone lacks a __meminit
annotation or the annotation of init_currently_empty_zone is wrong.
WARNING: vmlinux.o(.text+0x188aa2): Section mismatch in reference from the function move_pfn_range_to_zone() to the function .meminit.text:memmap_init_zone()
The function move_pfn_range_to_zone() references
the function __meminit memmap_init_zone().
This is often because move_pfn_range_to_zone lacks a __meminit
annotation or the annotation of memmap_init_zone is wrong.
WARNING: vmlinux.o(.text+0x188b3b): Section mismatch in reference from the function move_pfn_range_to_zone() to the function .meminit.text:init_currently_empty_zone()
The function move_pfn_range_to_zone() references
the function __meminit init_currently_empty_zone().
This is often because move_pfn_range_to_zone lacks a __meminit
annotation or the annotation of init_currently_empty_zone is wrong.
Both memmap_init_zone and init_currently_empty_zone are marked __meminit
but move_pfn_range_to_zone is used outside of __meminit sections (e.g.
devm_memremap_pages) so we have to hide it from the checker by __ref
annotation.
Link: http://lkml.kernel.org/r/20170515085827.16474-14-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch_add_memory gets for_device argument which then controls whether we
want to create memblocks for created memory sections. Simplify the
logic by telling whether we want memblocks directly rather than going
through pointless negation. This also makes the api easier to
understand because it is clear what we want rather than nothing telling
for_device which can mean anything.
This shouldn't introduce any functional change.
Link: http://lkml.kernel.org/r/20170515085827.16474-13-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens has noticed that he can generate overlapping zones for
ZONE_DMA and ZONE_NORMAL:
DMA [mem 0x0000000000000000-0x000000007fffffff]
Normal [mem 0x0000000080000000-0x000000017fffffff]
$ cat /sys/devices/system/memory/block_size_bytes
10000000
$ cat /sys/devices/system/memory/memory5/valid_zones
DMA
$ echo 0 > /sys/devices/system/memory/memory5/online
$ cat /sys/devices/system/memory/memory5/valid_zones
Normal
$ echo 1 > /sys/devices/system/memory/memory5/online
Normal
$ cat /proc/zoneinfo
Node 0, zone DMA
spanned 524288 <-----
present 458752
managed 455078
start_pfn: 0 <-----
Node 0, zone Normal
spanned 720896
present 589824
managed 571648
start_pfn: 327680 <-----
The reason is that we assume that the default zone for kernel onlining
is ZONE_NORMAL. This was a simplification introduced by the memory
hotplug rework and it is easily fixable by checking the range overlap in
the zone order and considering the first matching zone as the default
one. If there is no such zone then assume ZONE_NORMAL as we have been
doing so far.
Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online"
Link: http://lkml.kernel.org/r/20170601083746.4924-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens has noticed that the MMOP_ONLINE_KEEP is broken currently
$ grep . memory3?/valid_zones
memory34/valid_zones:Normal Movable
memory35/valid_zones:Normal Movable
memory36/valid_zones:Normal Movable
memory37/valid_zones:Normal Movable
$ echo online_movable > memory34/state
$ grep . memory3?/valid_zones
memory34/valid_zones:Movable
memory35/valid_zones:Movable
memory36/valid_zones:Movable
memory37/valid_zones:Movable
$ echo online > memory36/state
$ grep . memory3?/valid_zones
memory34/valid_zones:Movable
memory36/valid_zones:Normal
memory37/valid_zones:Movable
so we have effectively punched a hole into the movable zone.
The problem is that move_pfn_range() check for MMOP_ONLINE_KEEP is
wrong. It only checks whether the given range is already part of the
movable zone which is not the case here as only memory34 is in the zone.
Fix this by using allow_online_pfn_range(..., MMOP_ONLINE_KERNEL) if
that is false then we can be sure that movable onlining is the right
thing to do.
Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online"
Link: http://lkml.kernel.org/r/20170601083746.4924-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current memory hotplug implementation relies on having all the
struct pages associate with a zone/node during the physical hotplug
phase (arch_add_memory->__add_pages->__add_section->__add_zone). In the
vast majority of cases this means that they are added to ZONE_NORMAL.
This has been so since 9d99aaa31f ("[PATCH] x86_64: Support memory
hotadd without sparsemem") and it wasn't a big deal back then because
movable onlining didn't exist yet.
Much later memory hotplug wanted to (ab)use ZONE_MOVABLE for movable
onlining 511c2aba8f ("mm, memory-hotplug: dynamic configure movable
memory and portion memory") and then things got more complicated.
Rather than reconsidering the zone association which was no longer
needed (because the memory hotplug already depended on SPARSEMEM) a
convoluted semantic of zone shifting has been developed. Only the
currently last memblock or the one adjacent to the zone_movable can be
onlined movable. This essentially means that the online type changes as
the new memblocks are added.
Let's simulate memory hot online manually
$ echo 0x100000000 > /sys/devices/system/memory/probe
$ grep . /sys/devices/system/memory/memory32/valid_zones
Normal Movable
$ echo $((0x100000000+(128<<20))) > /sys/devices/system/memory/probe
$ grep . /sys/devices/system/memory/memory3?/valid_zones
/sys/devices/system/memory/memory32/valid_zones:Normal
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
$ echo $((0x100000000+2*(128<<20))) > /sys/devices/system/memory/probe
$ grep . /sys/devices/system/memory/memory3?/valid_zones
/sys/devices/system/memory/memory32/valid_zones:Normal
/sys/devices/system/memory/memory33/valid_zones:Normal
/sys/devices/system/memory/memory34/valid_zones:Normal Movable
$ echo online_movable > /sys/devices/system/memory/memory34/state
$ grep . /sys/devices/system/memory/memory3?/valid_zones
/sys/devices/system/memory/memory32/valid_zones:Normal
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Movable Normal
This is an awkward semantic because an udev event is sent as soon as the
block is onlined and an udev handler might want to online it based on
some policy (e.g. association with a node) but it will inherently race
with new blocks showing up.
This patch changes the physical online phase to not associate pages with
any zone at all. All the pages are just marked reserved and wait for
the onlining phase to be associated with the zone as per the online
request. There are only two requirements
- existing ZONE_NORMAL and ZONE_MOVABLE cannot overlap
- ZONE_NORMAL precedes ZONE_MOVABLE in physical addresses
the latter one is not an inherent requirement and can be changed in the
future. It preserves the current behavior and made the code slightly
simpler. This is subject to change in future.
This means that the same physical online steps as above will lead to the
following state: Normal Movable
/sys/devices/system/memory/memory32/valid_zones:Normal Movable
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory32/valid_zones:Normal Movable
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Normal Movable
/sys/devices/system/memory/memory32/valid_zones:Normal Movable
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Movable
Implementation:
The current move_pfn_range is reimplemented to check the above
requirements (allow_online_pfn_range) and then updates the respective
zone (move_pfn_range_to_zone), the pgdat and links all the pages in the
pfn range with the zone/node. __add_pages is updated to not require the
zone and only initializes sections in the range. This allowed to
simplify the arch_add_memory code (s390 could get rid of quite some of
code).
devm_memremap_pages is the only user of arch_add_memory which relies on
the zone association because it only hooks into the memory hotplug only
half way. It uses it to associate the new memory with ZONE_DEVICE but
doesn't allow it to be {on,off}lined via sysfs. This means that this
particular code path has to call move_pfn_range_to_zone explicitly.
The original zone shifting code is kept in place and will be removed in
the follow up patch for an easier review.
Please note that this patch also changes the original behavior when
offlining a memory block adjacent to another zone (Normal vs. Movable)
used to allow to change its movable type. This will be handled later.
[richard.weiyang@gmail.com: simplify zone_intersects()]
Link: http://lkml.kernel.org/r/20170616092335.5177-1-richard.weiyang@gmail.com
[richard.weiyang@gmail.com: remove duplicate call for set_page_links]
Link: http://lkml.kernel.org/r/20170616092335.5177-2-richard.weiyang@gmail.com
[akpm@linux-foundation.org: remove unused local `i']
Link: http://lkml.kernel.org/r/20170515085827.16474-12-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # For s390 bits
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pagetypeinfo_showblockcount_print skips over invalid pfns but it would
report pages which are offline because those have a valid pfn. Their
migrate type is misleading at best.
Now that we have pfn_to_online_page() we can use it instead of
pfn_valid() and fix this.
[mhocko@suse.com: fix build]
Link: http://lkml.kernel.org/r/20170519072225.GA13041@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170515085827.16474-11-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Joonsoo Kim <js1304@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__first_valid_page skips over invalid pfns in the range but it might
still stumble over offline pages. At least start_isolate_page_range
will mark those set_migratetype_isolate. This doesn't represent any
immediate AFAICS because alloc_contig_range will fail to isolate those
pages but it relies on not fully initialized page which will become a
problem later when we stop associating offline pages to zones. Use
pfn_to_online_page to handle this.
This is more a preparatory patch than a fix.
Link: http://lkml.kernel.org/r/20170515085827.16474-10-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__reset_isolation_suitable walks the whole zone pfn range and it tries
to jump over holes by checking the zone for each page. It might still
stumble over offline pages, though. Skip those by checking
pfn_to_online_page()
Link: http://lkml.kernel.org/r/20170515085827.16474-9-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__pageblock_pfn_to_page has two users currently, set_zone_contiguous
which checks whether the given zone contains holes and
pageblock_pfn_to_page which then carefully returns a first valid page
from the given pfn range for the given zone. This doesn't handle zones
which are not fully populated though. Memory pageblocks can be offlined
or might not have been onlined yet. In such a case the zone should be
considered to have holes otherwise pfn walkers can touch and play with
offline pages.
Current callers of pageblock_pfn_to_page in compaction seem to work
properly right now because they only isolate PageBuddy
(isolate_freepages_block) or PageLRU resp. __PageMovable
(isolate_migratepages_block) which will be always false for these pages.
It would be safer to skip these pages altogether, though.
In order to do this patch adds a new memory section state
(SECTION_IS_ONLINE) which is set in memory_present (during boot time) or
in online_pages_range during the memory hotplug. Similarly
offline_mem_sections clears the bit and it is called when the memory
range is offlined.
pfn_to_online_page helper is then added which check the mem section and
only returns a page if it is onlined already.
Use the new helper in __pageblock_pfn_to_page and skip the whole page
block in such a case.
[mhocko@suse.com: check valid section number in pfn_to_online_page (Vlastimil),
mark sections online after all struct pages are initialized in
online_pages_range (Vlastimil)]
Link: http://lkml.kernel.org/r/20170518164210.GD18333@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170515085827.16474-8-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory hotplug (add_memory_resource) has to reinitialize node
infrastructure if the node is offline (one which went through the
complete add_memory(); remove_memory() cycle). That involves node
registration to the kobj infrastructure (register_node), the proper
association with cpus (register_cpu_under_node) and finally creation of
node<->memblock symlinks (link_mem_sections).
The last part requires to know node_start_pfn and node_spanned_pages
which we currently have but a leter patch will postpone this
initialization to the onlining phase which happens later. In fact we do
not need to rely on the early pgdat initialization even now because the
currently hot added pfn range is currently known.
Split register_one_node into core which does all the common work for the
boot time NUMA initialization and the hotplug (__register_one_node).
register_one_node keeps the full initialization while hotplug calls
__register_one_node and manually calls link_mem_sections for the proper
range.
This shouldn't introduce any functional change.
Link: http://lkml.kernel.org/r/20170515085827.16474-6-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Device memory hotplug hooks into regular memory hotplug only half way.
It needs memory sections to track struct pages but there is no
need/desire to associate those sections with memory blocks and export
them to the userspace via sysfs because they cannot be onlined anyway.
This is currently expressed by for_device argument to arch_add_memory
which then makes sure to associate the given memory range with
ZONE_DEVICE. register_new_memory then relies on is_zone_device_section
to distinguish special memory hotplug from the regular one. While this
works now, later patches in this series want to move __add_zone outside
of arch_add_memory path so we have to come up with something else.
Add want_memblock down the __add_pages path and use it to control
whether the section->memblock association should be done.
arch_add_memory then just trivially want memblock for everything but
for_device hotplug.
remove_memory_section doesn't need is_zone_device_section either. We
can simply skip all the memblock specific cleanup if there is no
memblock for the given section.
This shouldn't introduce any functional change.
Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The primary purpose of this helper is to query the node state so use the
node id directly. This is a preparatory patch for later changes.
This shouldn't introduce any functional change
Link: http://lkml.kernel.org/r/20170515085827.16474-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: make movable onlining suck less", v4.
Movable onlining is a real hack with many downsides - mainly
reintroduction of lowmem/highmem issues we used to have on 32b systems -
but it is the only way to make the memory hotremove more reliable which
is something that people are asking for.
The current semantic of memory movable onlinening is really cumbersome,
however. The main reason for this is that the udev driven approach is
basically unusable because udev races with the memory probing while only
the last memory block or the one adjacent to the existing zone_movable
are allowed to be onlined movable. In short the criterion for the
successful online_movable changes under udev's feet. A reliable udev
approach would require a 2 phase approach where the first successful
movable online would have to check all the previous blocks and online
them in descending order. This is hard to be considered sane.
This patchset aims at making the onlining semantic more usable. First
of all it allows to online memory movable as long as it doesn't clash
with the existing ZONE_NORMAL. That means that ZONE_NORMAL and
ZONE_MOVABLE cannot overlap. Currently I preserve the original ordering
semantic so the zone always precedes the movable zone but I have plans
to remove this restriction in future because it is not really necessary.
First 3 patches are cleanups which should be ready to be merged right
away (unless I have missed something subtle of course).
Patch 4 deals with ZONE_DEVICE dependencies down the __add_pages path.
Patch 5 deals with implicit assumptions of register_one_node on pgdat
initialization.
Patches 6-10 deal with offline holes in the zone for pfn walkers. I
hope I got all of them right but people familiar with compaction should
double check this.
Patch 11 is the core of the change. In order to make it easier to
review I have tried it to be as minimalistic as possible and the large
code removal is moved to patch 14.
Patch 12 is a trivial follow up cleanup. Patch 13 fixes sparse warnings
and finally patch 14 removes the unused code.
I have tested the patches in kvm:
# qemu-system-x86_64 -enable-kvm -monitor pty -m 2G,slots=4,maxmem=4G -numa node,mem=1G -numa node,mem=1G ...
and then probed the additional memory by
(qemu) object_add memory-backend-ram,id=mem1,size=1G
(qemu) device_add pc-dimm,id=dimm1,memdev=mem1
Then I have used this simple script to probe the memory block by hand
# cat probe_memblock.sh
#!/bin/sh
BLOCK_NR=$1
# echo $((0x100000000+$BLOCK_NR*(128<<20))) > /sys/devices/system/memory/probe
# for i in $(seq 10); do sh probe_memblock.sh $i; done
# grep . /sys/devices/system/memory/memory3?/valid_zones 2>/dev/null
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Normal Movable
/sys/devices/system/memory/memory35/valid_zones:Normal Movable
/sys/devices/system/memory/memory36/valid_zones:Normal Movable
/sys/devices/system/memory/memory37/valid_zones:Normal Movable
/sys/devices/system/memory/memory38/valid_zones:Normal Movable
/sys/devices/system/memory/memory39/valid_zones:Normal Movable
The main difference to the original implementation is that all new
memblocks can be both online_kernel and online_movable initially because
there is no clash obviously. For the comparison the original
implementation would have
/sys/devices/system/memory/memory33/valid_zones:Normal
/sys/devices/system/memory/memory34/valid_zones:Normal
/sys/devices/system/memory/memory35/valid_zones:Normal
/sys/devices/system/memory/memory36/valid_zones:Normal
/sys/devices/system/memory/memory37/valid_zones:Normal
/sys/devices/system/memory/memory38/valid_zones:Normal
/sys/devices/system/memory/memory39/valid_zones:Normal Movable
Now
# echo online_movable > /sys/devices/system/memory/memory34/state
# grep . /sys/devices/system/memory/memory3?/valid_zones 2>/dev/null
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Movable
/sys/devices/system/memory/memory35/valid_zones:Movable
/sys/devices/system/memory/memory36/valid_zones:Movable
/sys/devices/system/memory/memory37/valid_zones:Movable
/sys/devices/system/memory/memory38/valid_zones:Movable
/sys/devices/system/memory/memory39/valid_zones:Movable
Block 33 can still be online both kernel and movable while all
the remaining can be only movable.
/proc/zonelist says
Node 0, zone Normal
pages free 0
min 0
low 0
high 0
spanned 0
present 0
--
Node 0, zone Movable
pages free 32753
min 85
low 117
high 149
spanned 32768
present 32768
A new memblock at a lower address will result in a new memblock (32)
which will still allow both Normal and Movable.
# sh probe_memblock.sh 0
# grep . /sys/devices/system/memory/memory3[2-5]/valid_zones 2>/dev/null
/sys/devices/system/memory/memory32/valid_zones:Normal Movable
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Movable
/sys/devices/system/memory/memory35/valid_zones:Movable
and online_kernel will convert it to the zone normal properly
while 33 can be still onlined both ways.
# echo online_kernel > /sys/devices/system/memory/memory32/state
# grep . /sys/devices/system/memory/memory3[2-5]/valid_zones 2>/dev/null
/sys/devices/system/memory/memory32/valid_zones:Normal
/sys/devices/system/memory/memory33/valid_zones:Normal Movable
/sys/devices/system/memory/memory34/valid_zones:Movable
/sys/devices/system/memory/memory35/valid_zones:Movable
/proc/zoneinfo will now tell
Node 0, zone Normal
pages free 65441
min 165
low 230
high 295
spanned 65536
present 65536
--
Node 0, zone Movable
pages free 32740
min 82
low 114
high 146
spanned 32768
present 32768
so both zones have one memblock spanned and present.
Onlining 39 should associate this block to the movable zone
# echo online > /sys/devices/system/memory/memory39/state
/proc/zoneinfo will now tell
Node 0, zone Normal
pages free 32765
min 80
low 112
high 144
spanned 32768
present 32768
--
Node 0, zone Movable
pages free 65501
min 160
low 225
high 290
spanned 196608
present 65536
so we will have a movable zone which spans 6 memblocks, 2 present and 4
representing a hole.
Offlining both movable blocks will lead to the zone with no present
pages which is the expected behavior I believe.
# echo offline > /sys/devices/system/memory/memory39/state
# echo offline > /sys/devices/system/memory/memory34/state
# grep -A6 "Movable\|Normal" /proc/zoneinfo
Node 0, zone Normal
pages free 32735
min 90
low 122
high 154
spanned 32768
present 32768
--
Node 0, zone Movable
pages free 0
min 0
low 0
high 0
spanned 196608
present 0
As a bonus we will get a nice cleanup in the memory hotplug codebase.
This patch (of 16):
init_currently_empty_zone doesn't have any error to return yet it is
still an int and callers try to be defensive and try to handle potential
error. Remove this nonsense and simplify all callers.
This patch shouldn't have any visible effect
Link: http://lkml.kernel.org/r/20170515085827.16474-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If there is no compound map for a THP (Transparent Huge Page), it is
possible that the map count of some sub-pages of the THP is 0. So it is
better to split the THP before swapping out. In this way, the sub-pages
not mapped will be freed, and we can avoid the unnecessary swap out
operations for these sub-pages.
Link: http://lkml.kernel.org/r/20170515112522.32457-6-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To swap out THP (Transparent Huage Page), before splitting the THP, the
swap cluster will be allocated and the THP will be added into the swap
cache. But it is possible that the THP cannot be split, so that we must
delete the THP from the swap cache and free the swap cluster. To avoid
that, in this patch, whether the THP can be split is checked firstly.
The check can only be done racy, but it is good enough for most cases.
With the patch, the swap out throughput improves 3.6% (from about
4.16GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
Link: http://lkml.kernel.org/r/20170515112522.32457-5-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for can_split_huge_page()]
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The add_to_swap aims to allocate swap_space(ie, swap slot and swapcache)
so if it fails due to lack of space in case of THP or something(hdd swap
but tries THP swapout) *caller* rather than add_to_swap itself should
split the THP page and retry it with base page which is more natural.
Link: http://lkml.kernel.org/r/20170515112522.32457-4-ying.huang@intel.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, get_swap_page takes struct page and allocates swap space according
to page size(ie, normal or THP) so it would be more cleaner to introduce
put_swap_page which is a counter function of get_swap_page. Then, it
calls right swap slot free function depending on page's size.
[ying.huang@intel.com: minor cleanup and fix]
Link: http://lkml.kernel.org/r/20170515112522.32457-3-ying.huang@intel.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Standardize the file operation variable names related to all four memory
management /proc interface files. Also change all the symbol
permissions (S_IRUGO) into octal permissions (0444) as it got complaints
from checkpatch.pl. This does not create any functional change to the
interface.
Link: http://lkml.kernel.org/r/20170427030632.8588-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a candidate stable_node_dup has been found and it can accept further
merges it can be refiled to the head of the list to speedup next
searches without altering which dup is found and how the dups accumulate
in the chain.
We already refiled it back to the head in the prune_stale_stable_nodes
case, but we didn't refile it if not pruning (which is more common).
And we also refiled it when it was already at the head which is
unnecessary (in the prune_stale_stable_nodes case, nr > 1 means there's
more than one dup in the chain, it doesn't mean it's not already at the
head of the chain).
The stable_node_chain list is single threaded and there's no SMP locking
contention so it should be faster to refile it to the head of the list
also if prune_stale_stable_nodes is false.
Profiling shows the refile happens 1.9% of the time when a dup is found
with a max_page_sharing limit setting of 3 (with max_page_sharing of 2
the refile never happens of course as there's never space for one more
merge) which is reasonably low. At higher max_page_sharing values it
should be much less frequent.
This is just an optimization.
Link: http://lkml.kernel.org/r/20170518173721.22316-4-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some static checker complains if chain/chain_prune returns a potentially
stale pointer.
There are two output parameters to chain/chain_prune, one is tree_page
the other is stable_node_dup. Like in get_ksm_page the caller has to
check tree_page is NULL before touching the stable_node. Similarly in
chain/chain_prune the caller has to check tree_page before touching the
stable_node_dup returned or the original stable_node passed as
parameter.
Because the tree_page is never returned as a stale pointer, it may be
more intuitive to return tree_page and to pass stable_node_dup for
reference instead of the reverse.
This patch purely swaps the two output parameters of chain/chain_prune
as a cleanup for the static checker and to mimic the get_ksm_page
behavior more closely. There's no change to the caller at all except
the swap, it's purely a cleanup and it is a noop from the caller point
of view.
Link: http://lkml.kernel.org/r/20170518173721.22316-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "KSMscale cleanup/optimizations".
There are no fixes here it's just minor cleanups and optimizations.
1/3 removes makes the "fix" for the stale stable_node fall in the
standard case without introducing new cases. Setting stable_node to
NULL was marginally safer, but stale pointer is still wiped from the
caller, this looks cleaner.
2/3 should fix the false positive from Dan's static checker.
3/3 is a microoptimization to apply the the refile of future merge
candidate dups at the head of the chain in all cases and to skip it in
one case where we did it and but it was a noop (to avoid checking if
it was already at the head but now we've to check it anyway so it got
optimized away).
This patch (of 3):
When the stable_node chain is collapsed we can as well set the caller
stable_node to match the returned stable_node_dup in chain_prune().
This way the collapse case becomes indistinguishable from the regular
stable_node case and we can remove two branches from the KSM page
migration handling slow paths.
While it was all correct this looks cleaner (and faster) as the caller has
to deal with fewer special cases.
Link: http://lkml.kernel.org/r/20170518173721.22316-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If merge_across_nodes was manually set to 0 (not the default value) by
the admin or a tuned profile on NUMA systems triggering cross-NODE page
migrations, a stable_node use after free could materialize.
If the chain is collapsed stable_node would point to the old chain that
was already freed. stable_node_dup would be the stable_node dup now
converted to a regular stable_node and indexed in the rbtree in
replacement of the freed stable_node chain (not anymore a dup).
This special case where the chain is collapsed in the NUMA replacement
path, is now detected by setting stable_node to NULL by the chain_prune
callee if it decides to collapse the chain. This tells the NUMA
replacement code that even if stable_node and stable_node_dup are
different, this is not a chain if stable_node is NULL, as the
stable_node_dup was converted to a regular stable_node and the chain was
collapsed.
It is generally safer for the callee to force the caller stable_node to
NULL the moment it become stale so any other mistake like this would
result in an instant Oops easier to debug than an use after free.
Otherwise the replace logic would act like if stable_node was a valid
chain, when in fact it was freed. Notably
stable_node_chain_add_dup(page_node, stable_node) would run on a stable
stable_node.
Andrey Ryabinin found the source of the use after free in chain_prune().
Link: http://lkml.kernel.org/r/20170512193805.8807-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Evgheni Dereveanchin <ederevea@redhat.com>
Tested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Without a max deduplication limit for each KSM page, the list of the
rmap_items associated to each stable_node can grow infinitely large.
During the rmap walk each entry can take up to ~10usec to process
because of IPIs for the TLB flushing (both for the primary MMU and the
secondary MMUs with the MMU notifier). With only 16GB of address space
shared in the same KSM page, that would amount to dozens of seconds of
kernel runtime.
A ~256 max deduplication factor will reduce the latencies of the rmap
walks on KSM pages to order of a few msec. Just doing the
cond_resched() during the rmap walks is not enough, the list size must
have a limit too, otherwise the caller could get blocked in (schedule
friendly) kernel computations for seconds, unexpectedly.
There's room for optimization to significantly reduce the IPI delivery
cost during the page_referenced(), but at least for page_migration in
the KSM case (used by hard NUMA bindings, compaction and NUMA balancing)
it may be inevitable to send lots of IPIs if each rmap_item->mm is
active on a different CPU and there are lots of CPUs. Even if we ignore
the IPI delivery cost, we've still to walk the whole KSM rmap list, so
we can't allow millions or billions (ulimited) number of entries in the
KSM stable_node rmap_item lists.
The limit is enforced efficiently by adding a second dimension to the
stable rbtree. So there are three types of stable_nodes: the regular
ones (identical as before, living in the first flat dimension of the
stable rbtree), the "chains" and the "dups".
Every "chain" and all "dups" linked into a "chain" enforce the invariant
that they represent the same write protected memory content, even if
each "dup" will be pointed by a different KSM page copy of that content.
This way the stable rbtree lookup computational complexity is unaffected
if compared to an unlimited max_sharing_limit. It is still enforced
that there cannot be KSM page content duplicates in the stable rbtree
itself.
Adding the second dimension to the stable rbtree only after the
max_page_sharing limit hits, provides for a zero memory footprint
increase on 64bit archs. The memory overhead of the per-KSM page
stable_tree and per virtual mapping rmap_item is unchanged. Only after
the max_page_sharing limit hits, we need to allocate a stable_tree
"chain" and rb_replace() the "regular" stable_node with the newly
allocated stable_node "chain". After that we simply add the "regular"
stable_node to the chain as a stable_node "dup" by linking hlist_dup in
the stable_node_chain->hlist. This way the "regular" (flat) stable_node
is converted to a stable_node "dup" living in the second dimension of
the stable rbtree.
During stable rbtree lookups the stable_node "chain" is identified as
stable_node->rmap_hlist_len == STABLE_NODE_CHAIN (aka
is_stable_node_chain()).
When dropping stable_nodes, the stable_node "dup" is identified as
stable_node->head == STABLE_NODE_DUP_HEAD (aka is_stable_node_dup()).
The STABLE_NODE_DUP_HEAD must be an unique valid pointer never used
elsewhere in any stable_node->head/node to avoid a clashes with the
stable_node->node.rb_parent_color pointer, and different from
&migrate_nodes. So the second field of &migrate_nodes is picked and
verified as always safe with a BUILD_BUG_ON in case the list_head
implementation changes in the future.
The STABLE_NODE_DUP is picked as a random negative value in
stable_node->rmap_hlist_len. rmap_hlist_len cannot become negative when
it's a "regular" stable_node or a stable_node "dup".
The stable_node_chain->nid is irrelevant. The stable_node_chain->kpfn
is aliased in a union with a time field used to rate limit the
stable_node_chain->hlist prunes.
The garbage collection of the stable_node_chain happens lazily during
stable rbtree lookups (as for all other kind of stable_nodes), or while
disabling KSM with "echo 2 >/sys/kernel/mm/ksm/run" while collecting the
entire stable rbtree.
While the "regular" stable_nodes and the stable_node "dups" must wait
for their underlying tree_page to be freed before they can be freed
themselves, the stable_node "chains" can be freed immediately if the
stable_node->hlist turns empty. This is because the "chains" are never
pointed by any page->mapping and they're effectively stable rbtree KSM
self contained metadata.
[akpm@linux-foundation.org: fix non-NUMA build]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When start_pfn equals end_pfn, __free_pages_memory() has no effect and
__free_memory_core() will finally return (end_pfn - start_pfn) = 0.
This patch returns 0 directly when start_pfn equals end_pfn.
Link: http://lkml.kernel.org/r/20170502131115.6650-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clang and its -Wunsequenced emits a warning
mm/vmscan.c:2961:25: error: unsequenced modification and access to 'gfp_mask' [-Wunsequenced]
.gfp_mask = (gfp_mask = current_gfp_context(gfp_mask)),
^
While it is not clear to me whether the initialization code violates the
specification (6.7.8 par 19 (ISO/IEC 9899) looks like it disagrees) the
code is quite confusing and worth cleaning up anyway. Fix this by
reusing sc.gfp_mask rather than the updated input gfp_mask parameter.
Link: http://lkml.kernel.org/r/20170510154030.10720-1-nick.desaulniers@gmail.com
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The protection map is only modified by per-arch init code so it can be
protected from writes after the init code runs.
This change was extracted from PaX where it's part of KERNEXEC.
Link: http://lkml.kernel.org/r/20170510174441.26163-1-danielmicay@gmail.com
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a number of times that we loop over NR_MEM_SECTIONS, looking
for section_present() on each section. But, when we have very large
physical address spaces (large MAX_PHYSMEM_BITS), NR_MEM_SECTIONS
becomes very large, making the loops quite long.
With MAX_PHYSMEM_BITS=46 and a section size of 128MB, the current loops
are 512k iterations, which we barely notice on modern hardware. But,
raising MAX_PHYSMEM_BITS higher (like we will see on systems that
support 5-level paging) makes this 64x longer and we start to notice,
especially on slower systems like simulators. A 10-second delay for
512k iterations is annoying. But, a 640- second delay is crippling.
This does not help if we have extremely sparse physical address spaces,
but those are quite rare. We expect that most of the "slow" systems
where this matters will also be quite small and non-sparse.
To fix this, we track the highest section we've ever encountered. This
lets us know when we will *never* see another section_present(), and
lets us break out of the loops earlier.
Doing the whole for_each_present_section_nr() macro is probably
overkill, but it will ensure that any future loop iterations that we
grow are more likely to be correct.
Kirrill said "It shaved almost 40 seconds from boot time in qemu with
5-level paging enabled for me".
Link: http://lkml.kernel.org/r/20170504174434.C45A4735@viggo.jf.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some hardened environments want to build kernels with slab_nomerge
already set (so that they do not depend on remembering to set the kernel
command line option). This is desired to reduce the risk of kernel heap
overflows being able to overwrite objects from merged caches and changes
the requirements for cache layout control, increasing the difficulty of
these attacks. By keeping caches unmerged, these kinds of exploits can
usually only damage objects in the same cache (though the risk to
metadata exploitation is unchanged).
Link: http://lkml.kernel.org/r/20170620230911.GA25238@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: David Windsor <dave@nullcore.net>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: David Windsor <dave@nullcore.net>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170616072918epcms5p4ff16c24ef8472b4c3b4371823cd87856@epcms5p4
Signed-off-by: Canjiang Lu <canjiang.lu@samsung.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kmem_cache->cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is
set, so wrap it with config CONFIG_SLUB_CPU_PARTIAL will save some space
on 32bit arch.
This patch wraps kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL
and wraps its sysfs too.
Link: http://lkml.kernel.org/r/20170502144533.10729-4-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cpu_slab's field partial is used when CONFIG_SLUB_CPU_PARTIAL is set,
which means we can save a pointer's space on each cpu for every slub
item.
This patch wraps cpu_slab->partial in CONFIG_SLUB_CPU_PARTIAL and wraps
its sysfs use too.
[akpm@linux-foundation.org: avoid strange 80-col tricks]
Link: http://lkml.kernel.org/r/20170502144533.10729-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each time a slab is deactivated, the page and freelist pointer should be
reset.
This patch just merges these two options into deactivate_slab().
Link: http://lkml.kernel.org/r/20170507031215.3130-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the code comes to this point, there are two cases:
1. cpu_slab is deactivated
2. cpu_slab is empty
In both cased, cpu_slab->freelist is NULL at this moment.
This patch removes the redundant assignment of cpu_slab->freelist.
Link: http://lkml.kernel.org/r/20170507031215.3130-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reinette reported the following crash:
BUG: Bad page state in process log2exe pfn:57600
page:ffffea00015d8000 count:0 mapcount:0 mapping: (null) index:0x20200
flags: 0x4000000000040019(locked|uptodate|dirty|swapbacked)
raw: 4000000000040019 0000000000000000 0000000000020200 00000000ffffffff
raw: ffffea00015d8020 ffffea00015d8020 0000000000000000 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
bad because of flags: 0x1(locked)
Modules linked in: rfcomm 8021q bnep intel_rapl x86_pkg_temp_thermal coretemp efivars btusb btrtl btbcm pwm_lpss_pci snd_hda_codec_hdmi btintel pwm_lpss snd_hda_codec_realtek snd_soc_skl snd_hda_codec_generic snd_soc_skl_ipc spi_pxa2xx_platform snd_soc_sst_ipc snd_soc_sst_dsp i2c_designware_platform i2c_designware_core snd_hda_ext_core snd_soc_sst_match snd_hda_intel snd_hda_codec mei_me snd_hda_core mei snd_soc_rt286 snd_soc_rl6347a snd_soc_core efivarfs
CPU: 1 PID: 354 Comm: log2exe Not tainted 4.12.0-rc7-test-test #19
Hardware name: Intel corporation NUC6CAYS/NUC6CAYB, BIOS AYAPLCEL.86A.0027.2016.1108.1529 11/08/2016
Call Trace:
bad_page+0x16a/0x1f0
free_pages_check_bad+0x117/0x190
free_hot_cold_page+0x7b1/0xad0
__put_page+0x70/0xa0
madvise_free_huge_pmd+0x627/0x7b0
madvise_free_pte_range+0x6f8/0x1150
__walk_page_range+0x6b5/0xe30
walk_page_range+0x13b/0x310
madvise_free_page_range.isra.16+0xad/0xd0
madvise_free_single_vma+0x2e4/0x470
SyS_madvise+0x8ce/0x1450
If somebody frees the page under us and we hold the last reference to
it, put_page() would attempt to free the page before unlocking it.
The fix is trivial reorder of operations.
Dave said:
"I came up with the exact same patch. For posterity, here's the test
case, generated by syzkaller and trimmed down by Reinette:
https://www.sr71.net/~dave/intel/log2.c
And the config that helps detect this:
https://www.sr71.net/~dave/intel/config-log2"
Fixes: b8d3c4c300 ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called")
Link: http://lkml.kernel.org/r/20170628101249.17879-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull percpu updates from Tejun Heo:
"These are the percpu changes for the v4.13-rc1 merge window. There are
a couple visibility related changes - tracepoints and allocator stats
through debugfs, along with __ro_after_init markings and a cosmetic
rename in percpu_counter.
Please note that the simple O(#elements_in_the_chunk) area allocator
used by percpu allocator is again showing scalability issues,
primarily with bpf allocating and freeing large number of counters.
Dennis is working on the replacement allocator and the percpu
allocator will be seeing increased churns in the coming cycles"
* 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: fix static checker warnings in pcpu_destroy_chunk
percpu: fix early calls for spinlock in pcpu_stats
percpu: resolve err may not be initialized in pcpu_alloc
percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch
percpu: add tracepoint support for percpu memory
percpu: expose statistics about percpu memory via debugfs
percpu: migrate percpu data structures to internal header
percpu: add missing lockdep_assert_held to func pcpu_free_area
mark most percpu globals as __ro_after_init
Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.
The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.
If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.
This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.
In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.
One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.
This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.
This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).
Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.
The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
The -EIO returned here can end up overriding whatever error is marked in
the address space, and be returned at fsync time, even when there is a
more appropriate error stored in the mapping.
Read errors are also sometimes tracked on a per-page level using
PG_error. Suppose we have a read error on a page, and then that page is
subsequently dirtied by overwriting the whole page. Writeback doesn't
clear PG_error, so we can then end up successfully writing back that
page and still return -EIO on fsync.
Worse yet, PG_error is cleared during a sync() syscall, but the -EIO
return from that is silently discarded. Any subsystem that is relying on
PG_error to report errors during fsync can easily lose writeback errors
due to this. All you need is a stray sync() call to wait for writeback
to complete and you've lost the error.
Since the handling of the PG_error flag is somewhat inconsistent across
subsystems, let's just rely on marking the address space when there are
writeback errors. Change the TestClearPageError call to ClearPageError,
and make __filemap_fdatawait_range a void return function.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
filemap_write_and_wait{_range} will return an error if writeback
initiation fails, but won't clear errors in the address_space. This is
particularly problematic on DAX, as filemap_fdatawrite* is
effectively synchronous there. Ensure that we clear the AS_EIO/AS_ENOSPC
flags when filemap_fdatawrite* returns an error.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Resetting this flag is almost certainly racy, and will be problematic
with some coming changes.
Make filemap_fdatawait_keep_errors return int, but not clear the flag(s).
Have jbd2 call it instead of filemap_fdatawait and don't attempt to
re-set the error flag if it fails.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
The error code should be negative. Since this ends up in the default case
anyway, this is harmless, but it's less confusing to negate it. Also,
later patches will require a negative error code here.
Link: http://lkml.kernel.org/r/20170525103355.6760-1-jlayton@redhat.com
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Provide a function, kmemdup_nul(), that will create a NUL-terminated string
from an unterminated character array where the length is known in advance.
This is better than kstrndup() in situations where we already know the
string length as the strnlen() in kstrndup() is superfluous.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Don't try to check PageError since that's potentially racy and not
necessarily going to be set after writepage errors out.
Instead, check the mapping for an error after writepage returns. That
should also help us detect errors that occurred if the VM tried to
clean the page earlier due to memory pressure.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
The callers all set it to 1.
Also, make it clear that this function will not set any sort of AS_*
error, and that the caller must do so if necessary. No existing caller
uses this on normal files, so none of them need it.
Also, add __must_check here since, in general, the callers need to handle
an error here in some fashion.
Link: http://lkml.kernel.org/r/20170525103303.6524-1-jlayton@redhat.com
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull x86 mm updates from Ingo Molnar:
"The main changes in this cycle were:
- Continued work to add support for 5-level paging provided by future
Intel CPUs. In particular we switch the x86 GUP code to the generic
implementation. (Kirill A. Shutemov)
- Continued work to add PCID CPU support to native kernels as well.
In this round most of the focus is on reworking/refreshing the TLB
flush infrastructure for the upcoming PCID changes. (Andy
Lutomirski)"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
x86/mm: Delete a big outdated comment about TLB flushing
x86/mm: Don't reenter flush_tlb_func_common()
x86/KASLR: Fix detection 32/64 bit bootloaders for 5-level paging
x86/ftrace: Exclude functions in head64.c from function-tracing
x86/mmap, ASLR: Do not treat unlimited-stack tasks as legacy mmap
x86/mm: Remove reset_lazy_tlbstate()
x86/ldt: Simplify the LDT switching logic
x86/boot/64: Put __startup_64() into .head.text
x86/mm: Add support for 5-level paging for KASLR
x86/mm: Make kernel_physical_mapping_init() support 5-level paging
x86/mm: Add sync_global_pgds() for configuration with 5-level paging
x86/boot/64: Add support of additional page table level during early boot
x86/boot/64: Rename init_level4_pgt and early_level4_pgt
x86/boot/64: Rewrite startup_64() in C
x86/boot/compressed: Enable 5-level paging during decompression stage
x86/boot/efi: Define __KERNEL32_CS GDT on 64-bit configurations
x86/boot/efi: Fix __KERNEL_CS definition of GDT entry on 64-bit configurations
x86/boot/efi: Cleanup initialization of GDT entries
x86/asm: Fix comment in return_from_SYSCALL_64()
x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation
...
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Add the SYSTEM_SCHEDULING bootup state to move various scheduler
debug checks earlier into the bootup. This turns silent and
sporadically deadly bugs into nice, deterministic splats. Fix some
of the splats that triggered. (Thomas Gleixner)
- A round of restructuring and refactoring of the load-balancing and
topology code (Peter Zijlstra)
- Another round of consolidating ~20 of incremental scheduler code
history: this time in terms of wait-queue nomenclature. (I didn't
get much feedback on these renaming patches, and we can still
easily change any names I might have misplaced, so if anyone hates
a new name, please holler and I'll fix it.) (Ingo Molnar)
- sched/numa improvements, fixes and updates (Rik van Riel)
- Another round of x86/tsc scheduler clock code improvements, in hope
of making it more robust (Peter Zijlstra)
- Improve NOHZ behavior (Frederic Weisbecker)
- Deadline scheduler improvements and fixes (Luca Abeni, Daniel
Bristot de Oliveira)
- Simplify and optimize the topology setup code (Lauro Ramos
Venancio)
- Debloat and decouple scheduler code some more (Nicolas Pitre)
- Simplify code by making better use of llist primitives (Byungchul
Park)
- ... plus other fixes and improvements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
sched/cputime: Refactor the cputime_adjust() code
sched/debug: Expose the number of RT/DL tasks that can migrate
sched/numa: Hide numa_wake_affine() from UP build
sched/fair: Remove effective_load()
sched/numa: Implement NUMA node level wake_affine()
sched/fair: Simplify wake_affine() for the single socket case
sched/numa: Override part of migrate_degrades_locality() when idle balancing
sched/rt: Move RT related code from sched/core.c to sched/rt.c
sched/deadline: Move DL related code from sched/core.c to sched/deadline.c
sched/cpuset: Only offer CONFIG_CPUSETS if SMP is enabled
sched/fair: Spare idle load balancing on nohz_full CPUs
nohz: Move idle balancer registration to the idle path
sched/loadavg: Generalize "_idle" naming to "_nohz"
sched/core: Drop the unused try_get_task_struct() helper function
sched/fair: WARN() and refuse to set buddy when !se->on_rq
sched/debug: Fix SCHED_WARN_ON() to return a value on !CONFIG_SCHED_DEBUG as well
sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming
sched/wait: Move bit_wait_table[] and related functionality from sched/core.c to sched/wait_bit.c
sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h>
sched/wait: Re-adjust macro line continuation backslashes in <linux/wait.h>
...
Pull core block/IO updates from Jens Axboe:
"This is the main pull request for the block layer for 4.13. Not a huge
round in terms of features, but there's a lot of churn related to some
core cleanups.
Note this depends on the UUID tree pull request, that Christoph
already sent out.
This pull request contains:
- A series from Christoph, unifying the error/stats codes in the
block layer. We now use blk_status_t everywhere, instead of using
different schemes for different places.
- Also from Christoph, some cleanups around request allocation and IO
scheduler interactions in blk-mq.
- And yet another series from Christoph, cleaning up how we handle
and do bounce buffering in the block layer.
- A blk-mq debugfs series from Bart, further improving on the support
we have for exporting internal information to aid debugging IO
hangs or stalls.
- Also from Bart, a series that cleans up the request initialization
differences across types of devices.
- A series from Goldwyn Rodrigues, allowing the block layer to return
failure if we will block and the user asked for non-blocking.
- Patch from Hannes for supporting setting loop devices block size to
that of the underlying device.
- Two series of patches from Javier, fixing various issues with
lightnvm, particular around pblk.
- A series from me, adding support for write hints. This comes with
NVMe support as well, so applications can help guide data placement
on flash to improve performance, latencies, and write
amplification.
- A series from Ming, improving and hardening blk-mq support for
stopping/starting and quiescing hardware queues.
- Two pull requests for NVMe updates. Nothing major on the feature
side, but lots of cleanups and bug fixes. From the usual crew.
- A series from Neil Brown, greatly improving the bio rescue set
support. Most notably, this kills the bio rescue work queues, if we
don't really need them.
- Lots of other little bug fixes that are all over the place"
* 'for-4.13/block' of git://git.kernel.dk/linux-block: (217 commits)
lightnvm: pblk: set line bitmap check under debug
lightnvm: pblk: verify that cache read is still valid
lightnvm: pblk: add initialization check
lightnvm: pblk: remove target using async. I/Os
lightnvm: pblk: use vmalloc for GC data buffer
lightnvm: pblk: use right metadata buffer for recovery
lightnvm: pblk: schedule if data is not ready
lightnvm: pblk: remove unused return variable
lightnvm: pblk: fix double-free on pblk init
lightnvm: pblk: fix bad le64 assignations
nvme: Makefile: remove dead build rule
blk-mq: map all HWQ also in hyperthreaded system
nvmet-rdma: register ib_client to not deadlock in device removal
nvme_fc: fix error recovery on link down.
nvmet_fc: fix crashes on bad opcodes
nvme_fc: Fix crash when nvme controller connection fails.
nvme_fc: replace ioabort msleep loop with completion
nvme_fc: fix double calls to nvme_cleanup_cmd()
nvme-fabrics: verify that a controller returns the correct NQN
nvme: simplify nvme_dev_attrs_are_visible
...
- introduce the new uuid_t/guid_t types that are going to replace
the somewhat confusing uuid_be/uuid_le types and make the terminology
fit the various specs, as well as the userspace libuuid library.
(me, based on a previous version from Amir)
- consolidated generic uuid/guid helper functions lifted from XFS
and libnvdimm (Amir and me)
- conversions to the new types and helpers (Amir, Andy and me)
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Merge tag 'uuid-for-4.13' of git://git.infradead.org/users/hch/uuid
Pull uuid subsystem from Christoph Hellwig:
"This is the new uuid subsystem, in which Amir, Andy and I have started
consolidating our uuid/guid helpers and improving the types used for
them. Note that various other subsystems have pulled in this tree, so
I'd like it to go in early.
UUID/GUID summary:
- introduce the new uuid_t/guid_t types that are going to replace the
somewhat confusing uuid_be/uuid_le types and make the terminology
fit the various specs, as well as the userspace libuuid library.
(me, based on a previous version from Amir)
- consolidated generic uuid/guid helper functions lifted from XFS and
libnvdimm (Amir and me)
- conversions to the new types and helpers (Amir, Andy and me)"
* tag 'uuid-for-4.13' of git://git.infradead.org/users/hch/uuid: (34 commits)
ACPI: hns_dsaf_acpi_dsm_guid can be static
mmc: sdhci-pci: make guid intel_dsm_guid static
uuid: Take const on input of uuid_is_null() and guid_is_null()
thermal: int340x_thermal: fix compile after the UUID API switch
thermal: int340x_thermal: Switch to use new generic UUID API
acpi: always include uuid.h
ACPI: Switch to use generic guid_t in acpi_evaluate_dsm()
ACPI / extlog: Switch to use new generic UUID API
ACPI / bus: Switch to use new generic UUID API
ACPI / APEI: Switch to use new generic UUID API
acpi, nfit: Switch to use new generic UUID API
MAINTAINERS: add uuid entry
tmpfs: generate random sb->s_uuid
scsi_debug: switch to uuid_t
nvme: switch to uuid_t
sysctl: switch to use uuid_t
partitions/ldm: switch to use uuid_t
overlayfs: use uuid_t instead of uuid_be
fs: switch ->s_uuid to uuid_t
ima/policy: switch to use uuid_t
...
Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
new architectures (and platforms) get ZONE_DEVICE support. Move to an
arch selected Kconfig option to save us the trouble.
Cc: linux-mm@kvack.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit bf5eb3de38 ("slub: separate out sysfs_slab_release() from
sysfs_slab_remove()") made slub sysfs file removals synchronous to
kmem_cache shutdown.
Unfortunately, this created a possible ABBA deadlock between slab_mutex
and sysfs draining mechanism triggering the following lockdep warning.
======================================================
[ INFO: possible circular locking dependency detected ]
4.10.0-test+ #48 Not tainted
-------------------------------------------------------
rmmod/1211 is trying to acquire lock:
(s_active#120){++++.+}, at: [<ffffffff81308073>] kernfs_remove+0x23/0x40
but task is already holding lock:
(slab_mutex){+.+.+.}, at: [<ffffffff8120f691>] kmem_cache_destroy+0x41/0x2d0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (slab_mutex){+.+.+.}:
lock_acquire+0xf6/0x1f0
__mutex_lock+0x75/0x950
mutex_lock_nested+0x1b/0x20
slab_attr_store+0x75/0xd0
sysfs_kf_write+0x45/0x60
kernfs_fop_write+0x13c/0x1c0
__vfs_write+0x28/0x120
vfs_write+0xc8/0x1e0
SyS_write+0x49/0xa0
entry_SYSCALL_64_fastpath+0x1f/0xc2
-> #0 (s_active#120){++++.+}:
__lock_acquire+0x10ed/0x1260
lock_acquire+0xf6/0x1f0
__kernfs_remove+0x254/0x320
kernfs_remove+0x23/0x40
sysfs_remove_dir+0x51/0x80
kobject_del+0x18/0x50
__kmem_cache_shutdown+0x3e6/0x460
kmem_cache_destroy+0x1fb/0x2d0
kvm_exit+0x2d/0x80 [kvm]
vmx_exit+0x19/0xa1b [kvm_intel]
SyS_delete_module+0x198/0x1f0
entry_SYSCALL_64_fastpath+0x1f/0xc2
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slab_mutex);
lock(s_active#120);
lock(slab_mutex);
lock(s_active#120);
*** DEADLOCK ***
2 locks held by rmmod/1211:
#0: (cpu_hotplug.dep_map){++++++}, at: [<ffffffff810a7877>] get_online_cpus+0x37/0x80
#1: (slab_mutex){+.+.+.}, at: [<ffffffff8120f691>] kmem_cache_destroy+0x41/0x2d0
stack backtrace:
CPU: 3 PID: 1211 Comm: rmmod Not tainted 4.10.0-test+ #48
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
Call Trace:
print_circular_bug+0x1be/0x210
__lock_acquire+0x10ed/0x1260
lock_acquire+0xf6/0x1f0
__kernfs_remove+0x254/0x320
kernfs_remove+0x23/0x40
sysfs_remove_dir+0x51/0x80
kobject_del+0x18/0x50
__kmem_cache_shutdown+0x3e6/0x460
kmem_cache_destroy+0x1fb/0x2d0
kvm_exit+0x2d/0x80 [kvm]
vmx_exit+0x19/0xa1b [kvm_intel]
SyS_delete_module+0x198/0x1f0
? SyS_delete_module+0x5/0x1f0
entry_SYSCALL_64_fastpath+0x1f/0xc2
It'd be the cleanest to deal with the issue by removing sysfs files
without holding slab_mutex before the rest of shutdown; however, given
the current code structure, it is pretty difficult to do so.
This patch punts sysfs file removal to a work item. Before commit
bf5eb3de38, the removal was punted to a RCU delayed work item which is
executed after release. Now, we're punting to a different work item on
shutdown which still maintains the goal removing the sysfs files earlier
when destroying kmem_caches.
Link: http://lkml.kernel.org/r/20170620204512.GI21326@htj.duckdns.org
Fixes: bf5eb3de38 ("slub: separate out sysfs_slab_release() from sysfs_slab_remove()")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Existing code that uses vmalloc_to_page() may assume that any address
for which is_vmalloc_addr() returns true may be passed into
vmalloc_to_page() to retrieve the associated struct page.
This is not un unreasonable assumption to make, but on architectures
that have CONFIG_HAVE_ARCH_HUGE_VMAP=y, it no longer holds, and we need
to ensure that vmalloc_to_page() does not go off into the weeds trying
to dereference huge PUDs or PMDs as table entries.
Given that vmalloc() and vmap() themselves never create huge mappings or
deal with compound pages at all, there is no correct answer in this
case, so return NULL instead, and issue a warning.
When reading /proc/kcore on arm64, you will hit an oops as soon as you
hit the huge mappings used for the various segments that make up the
mapping of vmlinux. With this patch applied, you will no longer hit the
oops, but the kcore contents willl be incorrect (these regions will be
zeroed out)
We are fixing this for kcore specifically, so it avoids vread() for
those regions. At least one other problematic user exists, i.e.,
/dev/kmem, but that is currently broken on arm64 for other reasons.
Link: http://lkml.kernel.org/r/20170609082226.26152-1-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: zhong jiang <zhongjiang@huawei.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a partial revert of commit 338a16ba15 ("mm, thp: copying user
pages must schedule on collapse") which added a cond_resched() to
__collapse_huge_page_copy().
On x86 with CONFIG_HIGHPTE, __collapse_huge_page_copy is called in
atomic context and thus scheduling is not possible. This is only a
possible config on arm and i386.
Although need_resched has been shown to be set for over 100 jiffies
while doing the iteration in __collapse_huge_page_copy, this is better
than doing
if (in_atomic())
cond_resched()
to cover only non-CONFIG_HIGHPTE configs.
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1706191341550.97821@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix expand_upwards() on architectures with an upward-growing stack (parisc,
metag and partly IA-64) to allow the stack to reliably grow exactly up to
the address space limit given by TASK_SIZE.
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of
mmap testing. That's the VM_BUG_ON(gap_end < gap_start) at the
end of unmapped_area_topdown(). Linus points out how MAP_FIXED
(which does not have to respect our stack guard gap intentions)
could result in gap_end below gap_start there. Fix that, and
the similar case in its alternative, unmapped_area().
Cc: stable@vger.kernel.org
Fixes: 1be7107fbe ("mm: larger stack guard gap, between vmas")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Debugged-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
From 2c06e795162cb306c9707ec51d3e1deadb37f573 Mon Sep 17 00:00:00 2001
From: Dennis Zhou <dennisz@fb.com>
Date: Wed, 21 Jun 2017 10:17:09 -0700
Commit 30a5b5367e ("percpu: expose statistics about percpu memory via
debugfs") introduces percpu memory statistics. pcpu_stats_chunk_alloc
takes the spin lock and disables/enables irqs on creation of a chunk. Irqs
are not enabled when the first chunk is initialized and thus kernels are
failing to boot with kernel debugging enabled. Fixed by changing _irq to
_irqsave and _irqrestore.
Fixes: 30a5b5367e ("percpu: expose statistics about percpu memory via debugfs")
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Reported-by: Alexander Levin <alexander.levin@verizon.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
From 4a42ecc735cff0015cc73c3d87edede631f4b885 Mon Sep 17 00:00:00 2001
From: Dennis Zhou <dennisz@fb.com>
Date: Wed, 21 Jun 2017 08:07:15 -0700
Add error message to out of space failure for atomic allocations in
percpu allocation path to fix -Wmaybe-uninitialized.
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
CRIU restores application mappings on the same place where they
were before Checkpoint. That means, that we need to move vDSO
and sigpage during restore on exactly the same place where
they were before C/R.
Make mremap() code update mm->context.{sigpage,vdso} pointers
during VMA move. Sigpage is used for landing after handling
a signal - if the pointer is not updated during moving, the
application might crash on any signal after mremap().
vDSO pointer on ARM32 is used only for setting auxv at this moment,
update it during mremap() in case of future usage.
Without those updates, current work of CRIU on ARM32 is not reliable.
Historically, we error Checkpointing if we find vDSO page on ARM32
and suggest user to disable CONFIG_VDSO.
But that's not correct - it goes from x86 where signal processing
is ended in vDSO blob. For arm32 it's sigpage, which is not disabled
with `CONFIG_VDSO=n'.
Looks like C/R was working by luck - because userspace on ARM32 at
this moment always sets SA_RESTORER.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Add support for tracepoints to the following events: chunk allocation,
chunk free, area allocation, area free, and area allocation failure.
This should let us replay percpu memory requests and evaluate
corresponding decisions.
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There is limited visibility into the use of percpu memory leaving us
unable to reason about correctness of parameters and overall use of
percpu memory. These counters and statistics aim to help understand
basic statistics about percpu memory such as number of allocations over
the lifetime, allocation sizes, and fragmentation.
New Config: PERCPU_STATS
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Migrates pcpu_chunk definition and a few percpu static variables to an
internal header file from mm/percpu.c. These will be used with debugfs
to expose statistics about percpu memory improving visibility regarding
allocations and fragmentation.
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Add a missing lockdep_assert_held for pcpu_lock to improve consistency
and safety throughout mm/percpu.c.
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Find out if the I/O will trigger a wait due to writeback. If yes,
return -EAGAIN.
Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
filemap_range_has_page() return true if the file's mapping has
a page within the range mentioned. This function will be used
to check if a write() call will cause a writeback of previous
writes.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Conflicts:
kernel/sched/Makefile
Pick up the waitqueue related renames - it didn't get much feedback,
so it appears to be uncontroversial. Famous last words? ;-)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So I've noticed a number of instances where it was not obvious from the
code whether ->task_list was for a wait-queue head or a wait-queue entry.
Furthermore, there's a number of wait-queue users where the lists are
not for 'tasks' but other entities (poll tables, etc.), in which case
the 'task_list' name is actively confusing.
To clear this all up, name the wait-queue head and entry list structure
fields unambiguously:
struct wait_queue_head::task_list => ::head
struct wait_queue_entry::task_list => ::entry
For example, this code:
rqw->wait.task_list.next != &wait->task_list
... is was pretty unclear (to me) what it's doing, while now it's written this way:
rqw->wait.head.next != &wait->entry
... which makes it pretty clear that we are iterating a list until we see the head.
Other examples are:
list_for_each_entry_safe(pos, next, &x->task_list, task_list) {
list_for_each_entry(wq, &fence->wait.task_list, task_list) {
... where it's unclear (to me) what we are iterating, and during review it's
hard to tell whether it's trying to walk a wait-queue entry (which would be
a bug), while now it's written as:
list_for_each_entry_safe(pos, next, &x->head, entry) {
list_for_each_entry(wq, &fence->wait.head, entry) {
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rename:
wait_queue_t => wait_queue_entry_t
'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.
Start sorting this out by renaming it to 'wait_queue_entry_t'.
This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.
This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.
Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.
One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications. For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).
Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.
Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.
Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e1587a4945 ("mm: vmpressure: fix sending wrong events on
underflow") declared that reclaimed pages exceed the scanned pages due
to the thp reclaim.
That is incorrect because THP will be spilt to normal page and loop
again, which will result in the scanned pages increment.
[akpm@linux-foundation.org: tweak comment text]
Link: http://lkml.kernel.org/r/1496824266-25235-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhongjiang <zhongjiang@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In do_huge_pmd_numa_page(), we attempt to handle a migrating thp pmd by
waiting until the pmd is unlocked before we return and retry. However,
we can race with migrate_misplaced_transhuge_page():
// do_huge_pmd_numa_page // migrate_misplaced_transhuge_page()
// Holds 0 refs on page // Holds 2 refs on page
vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
/* ... */
if (pmd_trans_migrating(*vmf->pmd)) {
page = pmd_page(*vmf->pmd);
spin_unlock(vmf->ptl);
ptl = pmd_lock(mm, pmd);
if (page_count(page) != 2)) {
/* roll back */
}
/* ... */
mlock_migrate_page(new_page, page);
/* ... */
spin_unlock(ptl);
put_page(page);
put_page(page); // page freed here
wait_on_page_locked(page);
goto out;
}
This can result in the freed page having its waiters flag set
unexpectedly, which trips the PAGE_FLAGS_CHECK_AT_PREP checks in the
page alloc/free functions. This has been observed on arm64 KVM guests.
We can avoid this by having do_huge_pmd_numa_page() take a reference on
the page before dropping the pmd lock, mirroring what we do in
__migration_entry_wait().
When we hit the race, migrate_misplaced_transhuge_page() will see the
reference and abort the migration, as it may do today in other cases.
Fixes: b8916634b7 ("mm: Prevent parallel splits during THP migration")
Link: http://lkml.kernel.org/r/1497349722-6731-2-git-send-email-will.deacon@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I saw need_resched() warnings when swapping on large swapfile (TBs)
because continuously allocating many pages in swap_cgroup_prepare() took
too long.
We already cond_resched when freeing page in swap_cgroup_swapoff(). Do
the same for the page allocation.
Link: http://lkml.kernel.org/r/20170604200109.17606-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory_failure() chooses a recovery action function based on the page
flags. For huge pages it uses the tail page flags which don't have
anything interesting set, resulting in:
> Memory failure: 0x9be3b4: Unknown page state
> Memory failure: 0x9be3b4: recovery action for unknown page: Failed
Instead, save a copy of the head page's flags if this is a huge page,
this means if there are no relevant flags for this tail page, we use the
head pages flags instead. This results in the me_huge_page() recovery
action being called:
> Memory failure: 0x9b7969: recovery action for huge page: Delayed
For hugepages that have not yet been allocated, this allows the hugepage
to be dequeued.
Fixes: 524fca1e73 ("HWPOISON: fix misjudgement of page_action() for errors on mlocked pages")
Link: http://lkml.kernel.org/r/20170524130204.21845-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch provides all required callbacks required by the generic
get_user_pages_fast() code and switches x86 over - and removes
the platform specific implementation.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170606113133.22974-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'v4.12-rc5' into for-4.13/block
We've already got a few conflicts and upcoming work depends on some of the
changes that have gone into mainline as regression fixes for this series.
Pull in 4.12-rc5 to resolve these conflicts and make it easier on down stream
trees to continue working on 4.13 changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This is used by overlayfs to encode intrasystem unique file handles.
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
For some file systems we still memcpy into it, but in various places this
already allows us to use the proper uuid helpers. More to come..
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
We have seen an early OOM killer invocation on ppc64 systems with
crashkernel=4096M:
kthreadd invoked oom-killer: gfp_mask=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=7, order=0, oom_score_adj=0
kthreadd cpuset=/ mems_allowed=7
CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.4.68-1.gd7fe927-default #1
Call Trace:
dump_stack+0xb0/0xf0 (unreliable)
dump_header+0xb0/0x258
out_of_memory+0x5f0/0x640
__alloc_pages_nodemask+0xa8c/0xc80
kmem_getpages+0x84/0x1a0
fallback_alloc+0x2a4/0x320
kmem_cache_alloc_node+0xc0/0x2e0
copy_process.isra.25+0x260/0x1b30
_do_fork+0x94/0x470
kernel_thread+0x48/0x60
kthreadd+0x264/0x330
ret_from_kernel_thread+0x5c/0xa4
Mem-Info:
active_anon:0 inactive_anon:0 isolated_anon:0
active_file:0 inactive_file:0 isolated_file:0
unevictable:0 dirty:0 writeback:0 unstable:0
slab_reclaimable:5 slab_unreclaimable:73
mapped:0 shmem:0 pagetables:0 bounce:0
free:0 free_pcp:0 free_cma:0
Node 7 DMA free:0kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:52428800kB managed:110016kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:320kB slab_unreclaimable:4672kB kernel_stack:1152kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 0 0 0
Node 7 DMA: 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 0kB
0 total pagecache pages
0 pages in swap cache
Swap cache stats: add 0, delete 0, find 0/0
Free swap = 0kB
Total swap = 0kB
819200 pages RAM
0 pages HighMem/MovableOnly
817481 pages reserved
0 pages cma reserved
0 pages hwpoisoned
the reason is that the managed memory is too low (only 110MB) while the
rest of the the 50GB is still waiting for the deferred intialization to
be done. update_defer_init estimates the initial memoty to initialize
to 2GB at least but it doesn't consider any memory allocated in that
range. In this particular case we've had
Reserving 4096MB of memory at 128MB for crashkernel (System RAM: 51200MB)
so the low 2GB is mostly depleted.
Fix this by considering memblock allocations in the initial static
initialization estimation. Move the max_initialise to
reset_deferred_meminit and implement a simple memblock_reserved_memory
helper which iterates all reserved blocks and sums the size of all that
start below the given address. The cumulative size is than added on top
of the initial estimation. This is still not ideal because
reset_deferred_meminit doesn't consider holes and so reservation might
be above the initial estimation whihch we ignore but let's make the
logic simpler until we really need to handle more complicated cases.
Fixes: 3a80a7fa79 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set")
Link: http://lkml.kernel.org/r/20170531104010.GI27783@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KVM uses get_user_pages() to resolve its stage2 faults. KVM sets the
FOLL_HWPOISON flag causing faultin_page() to return -EHWPOISON when it
finds a VM_FAULT_HWPOISON. KVM handles these hwpoison pages as a
special case. (check_user_page_hwpoison())
When huge pages are involved, this doesn't work so well.
get_user_pages() calls follow_hugetlb_page(), which stops early if it
receives VM_FAULT_HWPOISON from hugetlb_fault(), eventually returning
-EFAULT to the caller. The step to map this to -EHWPOISON based on the
FOLL_ flags is missing. The hwpoison special case is skipped, and
-EFAULT is returned to user-space, causing Qemu or kvmtool to exit.
Instead, move this VM_FAULT_ to errno mapping code into a header file
and use it from faultin_page() and follow_hugetlb_page().
With this, KVM works as expected.
This isn't a problem for arm64 today as we haven't enabled
MEMORY_FAILURE, but I can't see any reason this doesn't happen on x86
too, so I think this should be a fix. This doesn't apply earlier than
stable's v4.11.1 due to all sorts of cleanup.
[james.morse@arm.com: add vm_fault_to_errno() call to faultin_page()]
suggested.
Link: http://lkml.kernel.org/r/20170525171035.16359-1-james.morse@arm.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170524160900.28786-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.11.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kefeng reported that when running the follow test, the mlock count in
meminfo will increase permanently:
[1] testcase
linux:~ # cat test_mlockal
grep Mlocked /proc/meminfo
for j in `seq 0 10`
do
for i in `seq 4 15`
do
./p_mlockall >> log &
done
sleep 0.2
done
# wait some time to let mlock counter decrease and 5s may not enough
sleep 5
grep Mlocked /proc/meminfo
linux:~ # cat p_mlockall.c
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#define SPACE_LEN 4096
int main(int argc, char ** argv)
{
int ret;
void *adr = malloc(SPACE_LEN);
if (!adr)
return -1;
ret = mlockall(MCL_CURRENT | MCL_FUTURE);
printf("mlcokall ret = %d\n", ret);
ret = munlockall();
printf("munlcokall ret = %d\n", ret);
free(adr);
return 0;
}
In __munlock_pagevec() we should decrement NR_MLOCK for each page where
we clear the PageMlocked flag. Commit 1ebb7cc6a5 ("mm: munlock: batch
NR_MLOCK zone state updates") has introduced a bug where we don't
decrement NR_MLOCK for pages where we clear the flag, but fail to
isolate them from the lru list (e.g. when the pages are on some other
cpu's percpu pagevec). Since PageMlocked stays cleared, the NR_MLOCK
accounting gets permanently disrupted by this.
Fix it by counting the number of page whose PageMlock flag is cleared.
Fixes: 1ebb7cc6a5 (" mm: munlock: batch NR_MLOCK zone state updates")
Link: http://lkml.kernel.org/r/1495678405-54569-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joern Engel <joern@logfs.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: zhongjiang <zhongjiang@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On failing to migrate a page, soft_offline_huge_page() performs the
necessary update to the hugepage ref-count.
But when !hugepage_migration_supported() , unmap_and_move_hugepage()
also decrements the page ref-count for the hugepage. The combined
behaviour leaves the ref-count in an inconsistent state.
This leads to soft lockups when running the overcommitted hugepage test
from mce-tests suite.
Soft offlining pfn 0x83ed600 at process virtual address 0x400000000000
soft offline: 0x83ed600: migration failed 1, type 1fffc00000008008 (uptodate|head)
INFO: rcu_preempt detected stalls on CPUs/tasks:
Tasks blocked on level-0 rcu_node (CPUs 0-7): P2715
(detected by 7, t=5254 jiffies, g=963, c=962, q=321)
thugetlb_overco R running task 0 2715 2685 0x00000008
Call trace:
dump_backtrace+0x0/0x268
show_stack+0x24/0x30
sched_show_task+0x134/0x180
rcu_print_detail_task_stall_rnp+0x54/0x7c
rcu_check_callbacks+0xa74/0xb08
update_process_times+0x34/0x60
tick_sched_handle.isra.7+0x38/0x70
tick_sched_timer+0x4c/0x98
__hrtimer_run_queues+0xc0/0x300
hrtimer_interrupt+0xac/0x228
arch_timer_handler_phys+0x3c/0x50
handle_percpu_devid_irq+0x8c/0x290
generic_handle_irq+0x34/0x50
__handle_domain_irq+0x68/0xc0
gic_handle_irq+0x5c/0xb0
Address this by changing the putback_active_hugepage() in
soft_offline_huge_page() to putback_movable_pages().
This only triggers on systems that enable memory failure handling
(ARCH_SUPPORTS_MEMORY_FAILURE) but not hugepage migration
(!ARCH_ENABLE_HUGEPAGE_MIGRATION).
I imagine this wasn't triggered as there aren't many systems running
this configuration.
[akpm@linux-foundation.org: remove dead comment, per Naoya]
Link: http://lkml.kernel.org/r/20170525135146.32011-1-punit.agrawal@arm.com
Reported-by: Manoj Iyer <manoj.iyer@canonical.com>
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [3.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the pmd_devmap() checks were added by 5c7fb56e5e ("mm, dax:
dax-pmd vs thp-pmd vs hugetlbfs-pmd") to add better support for DAX huge
pages, they were all added to the end of if() statements after existing
pmd_trans_huge() checks. So, things like:
- if (pmd_trans_huge(*pmd))
+ if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
When further checks were added after pmd_trans_unstable() checks by
commit 7267ec008b ("mm: postpone page table allocation until we have
page to map") they were also added at the end of the conditional:
+ if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd))
This ordering is fine for pmd_trans_huge(), but doesn't work for
pmd_trans_unstable(). This is because DAX huge pages trip the bad_pmd()
check inside of pmd_none_or_trans_huge_or_clear_bad() (called by
pmd_trans_unstable()), which prints out a warning and returns 1. So, we
do end up doing the right thing, but only after spamming dmesg with
suspicious looking messages:
mm/pgtable-generic.c:39: bad pmd ffff8808daa49b88(84000001006000a5)
Reorder these checks in a helper so that pmd_devmap() is checked first,
avoiding the error messages, and add a comment explaining why the
ordering is important.
Fixes: commit 7267ec008b ("mm: postpone page table allocation until we have page to map")
Link: http://lkml.kernel.org/r/20170522215749.23516-1-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Pawel Lebioda <pawel.lebioda@intel.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Xiong Zhou <xzhou@redhat.com>
Cc: Eryu Guan <eguan@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Roman Gushchin has reported that the OOM killer can trivially selects
next OOM victim when a thread doing memory allocation from page fault
path was selected as first OOM victim.
allocate invoked oom-killer: gfp_mask=0x14280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null), order=0, oom_score_adj=0
allocate cpuset=/ mems_allowed=0
CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
oom_kill_process+0x219/0x3e0
out_of_memory+0x11d/0x480
__alloc_pages_slowpath+0xc84/0xd40
__alloc_pages_nodemask+0x245/0x260
alloc_pages_vma+0xa2/0x270
__handle_mm_fault+0xca9/0x10c0
handle_mm_fault+0xf3/0x210
__do_page_fault+0x240/0x4e0
trace_do_page_fault+0x37/0xe0
do_async_page_fault+0x19/0x70
async_page_fault+0x28/0x30
...
Out of memory: Kill process 492 (allocate) score 899 or sacrifice child
Killed process 492 (allocate) total-vm:2052368kB, anon-rss:1894576kB, file-rss:4kB, shmem-rss:0kB
allocate: page allocation failure: order:0, mode:0x14280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null)
allocate cpuset=/ mems_allowed=0
CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
__alloc_pages_slowpath+0xd32/0xd40
__alloc_pages_nodemask+0x245/0x260
alloc_pages_vma+0xa2/0x270
__handle_mm_fault+0xca9/0x10c0
handle_mm_fault+0xf3/0x210
__do_page_fault+0x240/0x4e0
trace_do_page_fault+0x37/0xe0
do_async_page_fault+0x19/0x70
async_page_fault+0x28/0x30
...
oom_reaper: reaped process 492 (allocate), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
...
allocate invoked oom-killer: gfp_mask=0x0(), nodemask=(null), order=0, oom_score_adj=0
allocate cpuset=/ mems_allowed=0
CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
oom_kill_process+0x219/0x3e0
out_of_memory+0x11d/0x480
pagefault_out_of_memory+0x68/0x80
mm_fault_error+0x8f/0x190
? handle_mm_fault+0xf3/0x210
__do_page_fault+0x4b2/0x4e0
trace_do_page_fault+0x37/0xe0
do_async_page_fault+0x19/0x70
async_page_fault+0x28/0x30
...
Out of memory: Kill process 233 (firewalld) score 10 or sacrifice child
Killed process 233 (firewalld) total-vm:246076kB, anon-rss:20956kB, file-rss:0kB, shmem-rss:0kB
There is a race window that the OOM reaper completes reclaiming the
first victim's memory while nothing but mutex_trylock() prevents the
first victim from calling out_of_memory() from pagefault_out_of_memory()
after memory allocation for page fault path failed due to being selected
as an OOM victim.
This is a side effect of commit 9a67f6488e ("mm: consolidate
GFP_NOFAIL checks in the allocator slowpath") because that commit
silently changed the behavior from
/* Avoid allocations with no watermarks from looping endlessly */
to
/*
* Give up allocations without trying memory reserves if selected
* as an OOM victim
*/
in __alloc_pages_slowpath() by moving the location to check TIF_MEMDIE
flag. I have noticed this change but I didn't post a patch because I
thought it is an acceptable change other than noise by warn_alloc()
because !__GFP_NOFAIL allocations are allowed to fail. But we
overlooked that failing memory allocation from page fault path makes
difference due to the race window explained above.
While it might be possible to add a check to pagefault_out_of_memory()
that prevents the first victim from calling out_of_memory() or remove
out_of_memory() from pagefault_out_of_memory(), changing
pagefault_out_of_memory() does not suppress noise by warn_alloc() when
allocating thread was selected as an OOM victim. There is little point
with printing similar backtraces and memory information from both
out_of_memory() and warn_alloc().
Instead, if we guarantee that current thread can try allocations with no
watermarks once when current thread looping inside
__alloc_pages_slowpath() was selected as an OOM victim, we can follow "who
can use memory reserves" rules and suppress noise by warn_alloc() and
prevent memory allocations from page fault path from calling
pagefault_out_of_memory().
If we take the comment literally, this patch would do
- if (test_thread_flag(TIF_MEMDIE))
- goto nopage;
+ if (alloc_flags == ALLOC_NO_WATERMARKS || (gfp_mask & __GFP_NOMEMALLOC))
+ goto nopage;
because gfp_pfmemalloc_allowed() returns false if __GFP_NOMEMALLOC is
given. But if I recall correctly (I couldn't find the message), the
condition is meant to apply to only OOM victims despite the comment.
Therefore, this patch preserves TIF_MEMDIE check.
Fixes: 9a67f6488e ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath")
Link: http://lkml.kernel.org/r/201705192112.IAF69238.OQOHSJLFOFFMtV@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Roman Gushchin <guro@fb.com>
Tested-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org> [4.11]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memcg_propagate_slab_attrs() abuses the sysfs attribute file functions
to propagate settings from the root kmem_cache to a newly created
kmem_cache. It does that with:
attr->show(root, buf);
attr->store(new, buf, strlen(bug);
Aside of being a lazy and absurd hackery this is broken because it does
not check the return value of the show() function.
Some of the show() functions return 0 w/o touching the buffer. That
means in such a case the store function is called with the stale content
of the previous show(). That causes nonsense like invoking
kmem_cache_shrink() on a newly created kmem_cache. In the worst case it
would cause handing in an uninitialized buffer.
This should be rewritten proper by adding a propagate() callback to
those slub_attributes which must be propagated and avoid that insane
conversion to and from ASCII, but that's too large for a hot fix.
Check at least the return value of the show() function, so calling
store() with stale content is prevented.
Steven said:
"It can cause a deadlock with get_online_cpus() that has been uncovered
by recent cpu hotplug and lockdep changes that Thomas and Peter have
been doing.
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(cpu_hotplug.lock);
lock(slab_mutex);
lock(cpu_hotplug.lock);
lock(slab_mutex);
*** DEADLOCK ***"
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705201244540.2255@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
