Tasks get their end of stack set to STACK_END_MAGIC with the
aim to catch stack overruns. Currently this feature does not
apply to init_task. This patch removes this restriction.
Note that a similar patch was posted by Prarit Bhargava
some time ago but was never merged:
http://marc.info/?l=linux-kernel&m=127144305403241&w=2
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The setup_node_data() function allocates a pg_data_t object,
inserts it into the node_data[] array and initializes the
following fields: node_id, node_start_pfn and
node_spanned_pages.
However, a few function calls later during the kernel boot,
free_area_init_node() re-initializes those fields, possibly with
setup_node_data() is not used.
This causes a small glitch when running Linux as a hyperv numa
guest:
SRAT: PXM 0 -> APIC 0x00 -> Node 0
SRAT: PXM 0 -> APIC 0x01 -> Node 0
SRAT: PXM 1 -> APIC 0x02 -> Node 1
SRAT: PXM 1 -> APIC 0x03 -> Node 1
SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
SRAT: Node 1 PXM 1 [mem 0x80200000-0xf7ffffff]
SRAT: Node 1 PXM 1 [mem 0x100000000-0x1081fffff]
NUMA: Node 1 [mem 0x80200000-0xf7ffffff] + [mem 0x100000000-0x1081fffff] -> [mem 0x80200000-0x1081fffff]
Initmem setup node 0 [mem 0x00000000-0x7fffffff]
NODE_DATA [mem 0x7ffdc000-0x7ffeffff]
Initmem setup node 1 [mem 0x80800000-0x1081fffff]
NODE_DATA [mem 0x1081ea000-0x1081fdfff]
crashkernel: memory value expected
[ffffea0000000000-ffffea0001ffffff] PMD -> [ffff88007de00000-ffff88007fdfffff] on node 0
[ffffea0002000000-ffffea00043fffff] PMD -> [ffff880105600000-ffff8801077fffff] on node 1
Zone ranges:
DMA [mem 0x00001000-0x00ffffff]
DMA32 [mem 0x01000000-0xffffffff]
Normal [mem 0x100000000-0x1081fffff]
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x00001000-0x0009efff]
node 0: [mem 0x00100000-0x7ffeffff]
node 1: [mem 0x80200000-0xf7ffffff]
node 1: [mem 0x100000000-0x1081fffff]
On node 0 totalpages: 524174
DMA zone: 64 pages used for memmap
DMA zone: 21 pages reserved
DMA zone: 3998 pages, LIFO batch:0
DMA32 zone: 8128 pages used for memmap
DMA32 zone: 520176 pages, LIFO batch:31
On node 1 totalpages: 524288
DMA32 zone: 7672 pages used for memmap
DMA32 zone: 491008 pages, LIFO batch:31
Normal zone: 520 pages used for memmap
Normal zone: 33280 pages, LIFO batch:7
In this dmesg, the SRAT table reports that the memory range for
node 1 starts at 0x80200000. However, the line starting with
"Initmem" reports that node 1 memory range starts at 0x80800000.
The "Initmem" line is reported by setup_node_data() and is
wrong, because the kernel ends up using the range as reported in
the SRAT table.
This commit drops all that dead code from setup_node_data(),
renames it to alloc_node_data() and adds a printk() to
free_area_init_node() so that we report a node's memory range
accurately.
Here's the same dmesg section with this patch applied:
SRAT: PXM 0 -> APIC 0x00 -> Node 0
SRAT: PXM 0 -> APIC 0x01 -> Node 0
SRAT: PXM 1 -> APIC 0x02 -> Node 1
SRAT: PXM 1 -> APIC 0x03 -> Node 1
SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
SRAT: Node 1 PXM 1 [mem 0x80200000-0xf7ffffff]
SRAT: Node 1 PXM 1 [mem 0x100000000-0x1081fffff]
NUMA: Node 1 [mem 0x80200000-0xf7ffffff] + [mem 0x100000000-0x1081fffff] -> [mem 0x80200000-0x1081fffff]
NODE_DATA(0) allocated [mem 0x7ffdc000-0x7ffeffff]
NODE_DATA(1) allocated [mem 0x1081ea000-0x1081fdfff]
crashkernel: memory value expected
[ffffea0000000000-ffffea0001ffffff] PMD -> [ffff88007de00000-ffff88007fdfffff] on node 0
[ffffea0002000000-ffffea00043fffff] PMD -> [ffff880105600000-ffff8801077fffff] on node 1
Zone ranges:
DMA [mem 0x00001000-0x00ffffff]
DMA32 [mem 0x01000000-0xffffffff]
Normal [mem 0x100000000-0x1081fffff]
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x00001000-0x0009efff]
node 0: [mem 0x00100000-0x7ffeffff]
node 1: [mem 0x80200000-0xf7ffffff]
node 1: [mem 0x100000000-0x1081fffff]
Initmem setup node 0 [mem 0x00001000-0x7ffeffff]
On node 0 totalpages: 524174
DMA zone: 64 pages used for memmap
DMA zone: 21 pages reserved
DMA zone: 3998 pages, LIFO batch:0
DMA32 zone: 8128 pages used for memmap
DMA32 zone: 520176 pages, LIFO batch:31
Initmem setup node 1 [mem 0x80200000-0x1081fffff]
On node 1 totalpages: 524288
DMA32 zone: 7672 pages used for memmap
DMA32 zone: 491008 pages, LIFO batch:31
Normal zone: 520 pages used for memmap
Normal zone: 33280 pages, LIFO batch:7
This commit was tested on a two node bare-metal NUMA machine and
Linux as a numa guest on hyperv and qemu/kvm.
PS: The wrong memory range reported by setup_node_data() seems to be
harmless in the current kernel because it's just not used. However,
that bad range is used in kernel 2.6.32 to initialize the old boot
memory allocator, which causes a crash during boot.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When hot-adding/removing memory, sync_global_pgds() is called
for synchronizing PGD to PGD entries of all processes MM. But
when hot-removing memory, sync_global_pgds() does not work
correctly.
At first, sync_global_pgds() checks whether target PGD is none
or not. And if PGD is none, the PGD is skipped. But when
hot-removing memory, PGD may be none since PGD may be cleared by
free_pud_table(). So when sync_global_pgds() is called after
hot-removing memory, sync_global_pgds() should not skip PGD even
if the PGD is none. And sync_global_pgds() must clear PGD
entries of all processes MM.
Currently sync_global_pgds() does not clear PGD entries of all
processes MM when hot-removing memory. So when hot adding
memory which is same memory range as removed memory after
hot-removing memory, following call traces are shown:
kernel BUG at arch/x86/mm/init_64.c:206!
...
[<ffffffff815e0c80>] kernel_physical_mapping_init+0x1b2/0x1d2
[<ffffffff815ced94>] init_memory_mapping+0x1d4/0x380
[<ffffffff8104aebd>] arch_add_memory+0x3d/0xd0
[<ffffffff815d03d9>] add_memory+0xb9/0x1b0
[<ffffffff81352415>] acpi_memory_device_add+0x1af/0x28e
[<ffffffff81325dc4>] acpi_bus_device_attach+0x8c/0xf0
[<ffffffff813413b9>] acpi_ns_walk_namespace+0xc8/0x17f
[<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
[<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
[<ffffffff813418ed>] acpi_walk_namespace+0x95/0xc5
[<ffffffff81326b4c>] acpi_bus_scan+0x9a/0xc2
[<ffffffff81326bff>] acpi_scan_bus_device_check+0x8b/0x12e
[<ffffffff81326cb5>] acpi_scan_device_check+0x13/0x15
[<ffffffff81320122>] acpi_os_execute_deferred+0x25/0x32
[<ffffffff8107e02b>] process_one_work+0x17b/0x460
[<ffffffff8107edfb>] worker_thread+0x11b/0x400
[<ffffffff8107ece0>] ? rescuer_thread+0x400/0x400
[<ffffffff81085aef>] kthread+0xcf/0xe0
[<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
[<ffffffff815fc76c>] ret_from_fork+0x7c/0xb0
[<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
This patch clears PGD entries of all processes MM when
sync_global_pgds() is called after hot-removing memory
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When hot-adding memory after hot-removing memory, following call
traces are shown:
kernel BUG at arch/x86/mm/init_64.c:206!
...
[<ffffffff815e0c80>] kernel_physical_mapping_init+0x1b2/0x1d2
[<ffffffff815ced94>] init_memory_mapping+0x1d4/0x380
[<ffffffff8104aebd>] arch_add_memory+0x3d/0xd0
[<ffffffff815d03d9>] add_memory+0xb9/0x1b0
[<ffffffff81352415>] acpi_memory_device_add+0x1af/0x28e
[<ffffffff81325dc4>] acpi_bus_device_attach+0x8c/0xf0
[<ffffffff813413b9>] acpi_ns_walk_namespace+0xc8/0x17f
[<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
[<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
[<ffffffff813418ed>] acpi_walk_namespace+0x95/0xc5
[<ffffffff81326b4c>] acpi_bus_scan+0x9a/0xc2
[<ffffffff81326bff>] acpi_scan_bus_device_check+0x8b/0x12e
[<ffffffff81326cb5>] acpi_scan_device_check+0x13/0x15
[<ffffffff81320122>] acpi_os_execute_deferred+0x25/0x32
[<ffffffff8107e02b>] process_one_work+0x17b/0x460
[<ffffffff8107edfb>] worker_thread+0x11b/0x400
[<ffffffff8107ece0>] ? rescuer_thread+0x400/0x400
[<ffffffff81085aef>] kthread+0xcf/0xe0
[<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
[<ffffffff815fc76c>] ret_from_fork+0x7c/0xb0
[<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
The patch-set fixes the issue.
This patch (of 2):
remove_pagetable() gets start argument and passes the argument
to sync_global_pgds(). In this case, the argument must not be
modified. If the argument is modified and passed to
sync_global_pgds(), sync_global_pgds() does not correctly
synchronize PGD to PGD entries of all processes MM since
synchronized range of memory [start, end] is wrong.
Unfortunately the start argument is modified in
remove_pagetable(). So this patch fixes the issue.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This fixes a compilation error in clang in that a linker section
attribute can't be added to a type:
arch/x86/mm/mmap.c:34:8: error: '__section__' attribute only applies to functions and global variables struct __read_mostly
...
By moving the section attribute to the variable declaration, the
desired effect is achieved.
Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409959005-11479-1-git-send-email-behanw@converseincode.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We should classify the espfix area as such only if we actually have
enabled the corresponding option. Otherwise the page table dump might
look confusing.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Link: http://lkml.kernel.org/r/1410114629-24523-1-git-send-email-minipli@googlemail.com
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The last user of set_pmd_pfn() went away in commit f03574f2d5, so this
has been dead code for over a year.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/include/asm/pgtable_32.h | 3 ---
arch/x86/mm/pgtable_32.c | 35 -----------------------------------
2 files changed, 38 deletions(-)
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x). This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.
Other use cases are for storing and retrieving data from the current
processors percpu area. __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.
__get_cpu_var() is defined as :
#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.
This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset. Thereby address calculations are avoided and less registers
are used when code is generated.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = &__get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(&y);
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, y);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(&x, this_cpu_ptr(&y), sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
__this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
__this_cpu_inc(y)
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Swap it for the more canonical lockdep_assert_held() which always
does the right thing - Guenter Roeck
* Assign the correct value to efi.runtime_version on arm64 so that all
the runtime services can be invoked - Semen Protsenko
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Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent
Pull EFI fixes from Matt Fleming:
* WARN_ON(!spin_is_locked()) always triggers on non-SMP machines.
Swap it for the more canonical lockdep_assert_held() which always
does the right thing - Guenter Roeck
* Assign the correct value to efi.runtime_version on arm64 so that all
the runtime services can be invoked - Semen Protsenko
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A sparse warning is generated about
'tlb_single_page_flush_ceiling' not being declared.
arch/x86/mm/tlb.c:177:15: warning: symbol
'tlb_single_page_flush_ceiling' was not declared. Should it be static?
Since it isn't used anywhere outside this file, fix the warning
by making it static.
Also, optimize the use of this variable by adding the
__read_mostly directive, as suggested by David Rientjes.
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Link: http://lkml.kernel.org/r/1407569913-4035-1-git-send-email-jmmahler@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch introduces zone_for_memory() to arch_add_memory() on x86_32
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces zone_for_memory() to arch_add_memory() on x86_64
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a comment describing the circumstances in which
__lock_page_or_retry() will or will not release the mmap_sem when
returning 0.
Add comments to lock_page_or_retry()'s callers (filemap_fault(),
do_swap_page()) noting the impact on VM_FAULT_RETRY returns.
Add comments on up the call tree, particularly replacing the false "We
return with mmap_sem still held" comments.
Signed-off-by: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 mm changes from Ingo Molnar:
"The main change in this cycle is the rework of the TLB range flushing
code, to simplify, fix and consolidate the code. By Dave Hansen"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Set TLB flush tunable to sane value (33)
x86/mm: New tunable for single vs full TLB flush
x86/mm: Add tracepoints for TLB flushes
x86/mm: Unify remote INVLPG code
x86/mm: Fix missed global TLB flush stat
x86/mm: Rip out complicated, out-of-date, buggy TLB flushing
x86/mm: Clean up the TLB flushing code
x86/smep: Be more informative when signalling an SMEP fault
This has been run through Intel's LKP tests across a wide range
of modern sytems and workloads and it wasn't shown to make a
measurable performance difference positive or negative.
Now that we have some shiny new tracepoints, we can actually
figure out what the heck is going on.
During a kernel compile, 60% of the flush_tlb_mm_range() calls
are for a single page. It breaks down like this:
size percent percent<=
V V V
GLOBAL: 2.20% 2.20% avg cycles: 2283
1: 56.92% 59.12% avg cycles: 1276
2: 13.78% 72.90% avg cycles: 1505
3: 8.26% 81.16% avg cycles: 1880
4: 7.41% 88.58% avg cycles: 2447
5: 1.73% 90.31% avg cycles: 2358
6: 1.32% 91.63% avg cycles: 2563
7: 1.14% 92.77% avg cycles: 2862
8: 0.62% 93.39% avg cycles: 3542
9: 0.08% 93.47% avg cycles: 3289
10: 0.43% 93.90% avg cycles: 3570
11: 0.20% 94.10% avg cycles: 3767
12: 0.08% 94.18% avg cycles: 3996
13: 0.03% 94.20% avg cycles: 4077
14: 0.02% 94.23% avg cycles: 4836
15: 0.04% 94.26% avg cycles: 5699
16: 0.06% 94.32% avg cycles: 5041
17: 0.57% 94.89% avg cycles: 5473
18: 0.02% 94.91% avg cycles: 5396
19: 0.03% 94.95% avg cycles: 5296
20: 0.02% 94.96% avg cycles: 6749
21: 0.18% 95.14% avg cycles: 6225
22: 0.01% 95.15% avg cycles: 6393
23: 0.01% 95.16% avg cycles: 6861
24: 0.12% 95.28% avg cycles: 6912
25: 0.05% 95.32% avg cycles: 7190
26: 0.01% 95.33% avg cycles: 7793
27: 0.01% 95.34% avg cycles: 7833
28: 0.01% 95.35% avg cycles: 8253
29: 0.08% 95.42% avg cycles: 8024
30: 0.03% 95.45% avg cycles: 9670
31: 0.01% 95.46% avg cycles: 8949
32: 0.01% 95.46% avg cycles: 9350
33: 3.11% 98.57% avg cycles: 8534
34: 0.02% 98.60% avg cycles: 10977
35: 0.02% 98.62% avg cycles: 11400
We get in to dimishing returns pretty quickly. On pre-IvyBridge
CPUs, we used to set the limit at 8 pages, and it was set at 128
on IvyBrige. That 128 number looks pretty silly considering that
less than 0.5% of the flushes are that large.
The previous code tried to size this number based on the size of
the TLB. Good idea, but it's error-prone, needs maintenance
(which it didn't get up to now), and probably would not matter in
practice much.
Settting it to 33 means that we cover the mallopt
M_TRIM_THRESHOLD, which is the most universally common size to do
flushes.
That's the short version. Here's the long one for why I chose 33:
1. These numbers have a constant bias in the timestamps from the
tracing. Probably counts for a couple hundred cycles in each of
these tests, but it should be fairly _even_ across all of them.
The smallest delta between the tracepoints I have ever seen is
335 cycles. This is one reason the cycles/page cost goes down in
general as the flushes get larger. The true cost is nearer to
100 cycles.
2. A full flush is more expensive than a single invlpg, but not
by much (single percentages).
3. A dtlb miss is 17.1ns (~45 cycles) and a itlb miss is 13.0ns
(~34 cycles). At those rates, refilling the 512-entry dTLB takes
22,000 cycles.
4. 22,000 cycles is approximately the equivalent of doing 85
invlpg operations. But, the odds are that the TLB can
actually be filled up faster than that because TLB misses that
are close in time also tend to leverage the same caches.
6. ~98% of flushes are <=33 pages. There are a lot of flushes of
33 pages, probably because libc's M_TRIM_THRESHOLD is set to
128k (32 pages)
7. I've found no consistent data to support changing the IvyBridge
vs. SandyBridge tunable by a factor of 16
I used the performance counters on this hardware (IvyBridge i5-3320M)
to figure out the tlb miss costs:
ocperf.py stat -e dtlb_load_misses.walk_duration,dtlb_load_misses.walk_completed,dtlb_store_misses.walk_duration,dtlb_store_misses.walk_completed,itlb_misses.walk_duration,itlb_misses.walk_completed,itlb.itlb_flush
7,720,030,970 dtlb_load_misses_walk_duration [57.13%]
169,856,353 dtlb_load_misses_walk_completed [57.15%]
708,832,859 dtlb_store_misses_walk_duration [57.17%]
19,346,823 dtlb_store_misses_walk_completed [57.17%]
2,779,687,402 itlb_misses_walk_duration [57.15%]
82,241,148 itlb_misses_walk_completed [57.13%]
770,717 itlb_itlb_flush [57.11%]
Show that a dtlb miss is 17.1ns (~45 cycles) and a itlb miss is 13.0ns
(~34 cycles). At those rates, refilling the 512-entry dTLB takes
22,000 cycles. On a SandyBridge system with more cores and larger
caches, those are dtlb=13.4ns and itlb=9.5ns.
cat perf.stat.txt | perl -pe 's/,//g'
| awk '/itlb_misses_walk_duration/ { icyc+=$1 }
/itlb_misses_walk_completed/ { imiss+=$1 }
/dtlb_.*_walk_duration/ { dcyc+=$1 }
/dtlb_.*.*completed/ { dmiss+=$1 }
END {print "itlb cyc/miss: ", icyc/imiss, " dtlb cyc/miss: ", dcyc/dmiss, " ----- ", icyc,imiss, dcyc,dmiss }
On Westmere CPUs, the counters to use are: itlb_flush,itlb_misses.walk_cycles,itlb_misses.any,dtlb_misses.walk_cycles,dtlb_misses.any
The assumptions that this code went in under:
https://lkml.org/lkml/2012/6/12/119 say that a flush and a refill are
about 100ns. Being generous, that is over by a factor of 6 on the
refill side, although it is fairly close on the cost of an invlpg.
An increase of a single invlpg operation seems to lengthen the flush
range operation by about 200 cycles. Here is one example of the data
collected for flushing 10 and 11 pages (full data are below):
10: 0.43% 93.90% avg cycles: 3570 cycles/page: 357 samples: 4714
11: 0.20% 94.10% avg cycles: 3767 cycles/page: 342 samples: 2145
How to generate this table:
echo 10000 > /sys/kernel/debug/tracing/buffer_size_kb
echo x86-tsc > /sys/kernel/debug/tracing/trace_clock
echo 'reason != 0' > /sys/kernel/debug/tracing/events/tlb/tlb_flush/filter
echo 1 > /sys/kernel/debug/tracing/events/tlb/tlb_flush/enable
Pipe the trace output in to this script:
http://sr71.net/~dave/intel/201402-tlb/trace-time-diff-process.pl.txt
Note that these data were gathered with the invlpg threshold set to
150 pages. Only data points with >=50 of samples were printed:
Flush % of %<=
in flush this
pages es size
------------------------------------------------------------------------------
-1: 2.20% 2.20% avg cycles: 2283 cycles/page: xxxx samples: 23960
1: 56.92% 59.12% avg cycles: 1276 cycles/page: 1276 samples: 620895
2: 13.78% 72.90% avg cycles: 1505 cycles/page: 752 samples: 150335
3: 8.26% 81.16% avg cycles: 1880 cycles/page: 626 samples: 90131
4: 7.41% 88.58% avg cycles: 2447 cycles/page: 611 samples: 80877
5: 1.73% 90.31% avg cycles: 2358 cycles/page: 471 samples: 18885
6: 1.32% 91.63% avg cycles: 2563 cycles/page: 427 samples: 14397
7: 1.14% 92.77% avg cycles: 2862 cycles/page: 408 samples: 12441
8: 0.62% 93.39% avg cycles: 3542 cycles/page: 442 samples: 6721
9: 0.08% 93.47% avg cycles: 3289 cycles/page: 365 samples: 917
10: 0.43% 93.90% avg cycles: 3570 cycles/page: 357 samples: 4714
11: 0.20% 94.10% avg cycles: 3767 cycles/page: 342 samples: 2145
12: 0.08% 94.18% avg cycles: 3996 cycles/page: 333 samples: 864
13: 0.03% 94.20% avg cycles: 4077 cycles/page: 313 samples: 289
14: 0.02% 94.23% avg cycles: 4836 cycles/page: 345 samples: 236
15: 0.04% 94.26% avg cycles: 5699 cycles/page: 379 samples: 390
16: 0.06% 94.32% avg cycles: 5041 cycles/page: 315 samples: 643
17: 0.57% 94.89% avg cycles: 5473 cycles/page: 321 samples: 6229
18: 0.02% 94.91% avg cycles: 5396 cycles/page: 299 samples: 224
19: 0.03% 94.95% avg cycles: 5296 cycles/page: 278 samples: 367
20: 0.02% 94.96% avg cycles: 6749 cycles/page: 337 samples: 185
21: 0.18% 95.14% avg cycles: 6225 cycles/page: 296 samples: 1964
22: 0.01% 95.15% avg cycles: 6393 cycles/page: 290 samples: 83
23: 0.01% 95.16% avg cycles: 6861 cycles/page: 298 samples: 61
24: 0.12% 95.28% avg cycles: 6912 cycles/page: 288 samples: 1307
25: 0.05% 95.32% avg cycles: 7190 cycles/page: 287 samples: 533
26: 0.01% 95.33% avg cycles: 7793 cycles/page: 299 samples: 94
27: 0.01% 95.34% avg cycles: 7833 cycles/page: 290 samples: 66
28: 0.01% 95.35% avg cycles: 8253 cycles/page: 294 samples: 73
29: 0.08% 95.42% avg cycles: 8024 cycles/page: 276 samples: 846
30: 0.03% 95.45% avg cycles: 9670 cycles/page: 322 samples: 296
31: 0.01% 95.46% avg cycles: 8949 cycles/page: 288 samples: 79
32: 0.01% 95.46% avg cycles: 9350 cycles/page: 292 samples: 60
33: 3.11% 98.57% avg cycles: 8534 cycles/page: 258 samples: 33936
34: 0.02% 98.60% avg cycles: 10977 cycles/page: 322 samples: 268
35: 0.02% 98.62% avg cycles: 11400 cycles/page: 325 samples: 177
36: 0.01% 98.63% avg cycles: 11504 cycles/page: 319 samples: 161
37: 0.02% 98.65% avg cycles: 11596 cycles/page: 313 samples: 182
38: 0.02% 98.66% avg cycles: 11850 cycles/page: 311 samples: 195
39: 0.01% 98.68% avg cycles: 12158 cycles/page: 311 samples: 128
40: 0.01% 98.68% avg cycles: 11626 cycles/page: 290 samples: 78
41: 0.04% 98.73% avg cycles: 11435 cycles/page: 278 samples: 477
42: 0.01% 98.73% avg cycles: 12571 cycles/page: 299 samples: 74
43: 0.01% 98.74% avg cycles: 12562 cycles/page: 292 samples: 78
44: 0.01% 98.75% avg cycles: 12991 cycles/page: 295 samples: 108
45: 0.01% 98.76% avg cycles: 13169 cycles/page: 292 samples: 78
46: 0.02% 98.78% avg cycles: 12891 cycles/page: 280 samples: 261
47: 0.01% 98.79% avg cycles: 13099 cycles/page: 278 samples: 67
48: 0.01% 98.80% avg cycles: 13851 cycles/page: 288 samples: 77
49: 0.01% 98.80% avg cycles: 13749 cycles/page: 280 samples: 66
50: 0.01% 98.81% avg cycles: 13949 cycles/page: 278 samples: 73
52: 0.00% 98.82% avg cycles: 14243 cycles/page: 273 samples: 52
54: 0.01% 98.83% avg cycles: 15312 cycles/page: 283 samples: 87
55: 0.01% 98.84% avg cycles: 15197 cycles/page: 276 samples: 109
56: 0.02% 98.86% avg cycles: 15234 cycles/page: 272 samples: 208
57: 0.00% 98.86% avg cycles: 14888 cycles/page: 261 samples: 53
58: 0.01% 98.87% avg cycles: 15037 cycles/page: 259 samples: 59
59: 0.01% 98.87% avg cycles: 15752 cycles/page: 266 samples: 63
62: 0.00% 98.89% avg cycles: 16222 cycles/page: 261 samples: 54
64: 0.02% 98.91% avg cycles: 17179 cycles/page: 268 samples: 248
65: 0.12% 99.03% avg cycles: 18762 cycles/page: 288 samples: 1324
85: 0.00% 99.10% avg cycles: 21649 cycles/page: 254 samples: 50
127: 0.01% 99.18% avg cycles: 32397 cycles/page: 255 samples: 75
128: 0.13% 99.31% avg cycles: 31711 cycles/page: 247 samples: 1466
129: 0.18% 99.49% avg cycles: 33017 cycles/page: 255 samples: 1927
181: 0.33% 99.84% avg cycles: 2489 cycles/page: 13 samples: 3547
256: 0.05% 99.91% avg cycles: 2305 cycles/page: 9 samples: 550
512: 0.03% 99.95% avg cycles: 2133 cycles/page: 4 samples: 304
1512: 0.01% 99.99% avg cycles: 3038 cycles/page: 2 samples: 65
Here are the tlb counters during a 10-second slice of a kernel compile
for a SandyBridge system. It's better than IvyBridge, but probably
due to the larger caches since this was one of the 'X' extreme parts.
10,873,007,282 dtlb_load_misses_walk_duration
250,711,333 dtlb_load_misses_walk_completed
1,212,395,865 dtlb_store_misses_walk_duration
31,615,772 dtlb_store_misses_walk_completed
5,091,010,274 itlb_misses_walk_duration
163,193,511 itlb_misses_walk_completed
1,321,980 itlb_itlb_flush
10.008045158 seconds time elapsed
# cat perf.stat.1392743721.txt | perl -pe 's/,//g' | awk '/itlb_misses_walk_duration/ { icyc+=$1 } /itlb_misses_walk_completed/ { imiss+=$1 } /dtlb_.*_walk_duration/ { dcyc+=$1 } /dtlb_.*.*completed/ { dmiss+=$1 } END {print "itlb cyc/miss: ", icyc/imiss/3.3, " dtlb cyc/miss: ", dcyc/dmiss/3.3, " ----- ", icyc,imiss, dcyc,dmiss }'
itlb ns/miss: 9.45338 dtlb ns/miss: 12.9716
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154103.10C1115E@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Most of the logic here is in the documentation file. Please take
a look at it.
I know we've come full-circle here back to a tunable, but this
new one is *WAY* simpler. I challenge anyone to describe in one
sentence how the old one worked. Here's the way the new one
works:
If we are flushing more pages than the ceiling, we use
the full flush, otherwise we use per-page flushes.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154101.12B52CAF@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
We don't have any good way to figure out what kinds of flushes
are being attempted. Right now, we can try to use the vm
counters, but those only tell us what we actually did with the
hardware (one-by-one vs full) and don't tell us what was actually
_requested_.
This allows us to select out "interesting" TLB flushes that we
might want to optimize (like the ranged ones) and ignore the ones
that we have very little control over (the ones at context
switch).
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154059.4C96CBA5@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
There are currently three paths through the remote flush code:
1. full invalidation
2. single page invalidation using invlpg
3. ranged invalidation using invlpg
This takes 2 and 3 and combines them in to a single path by
making the single-page one just be the start and end be start
plus a single page. This makes placement of our tracepoint easier.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154058.E0F90408@viggo.jf.intel.com
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
If we take the
if (end == TLB_FLUSH_ALL || vmflag & VM_HUGETLB) {
local_flush_tlb();
goto out;
}
path out of flush_tlb_mm_range(), we will have flushed the tlb,
but not incremented NR_TLB_LOCAL_FLUSH_ALL. This unifies the
way out of the function so that we always take a single path when
doing a full tlb flush.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154056.FF763B76@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
I think the flush_tlb_mm_range() code that tries to tune the
flush sizes based on the CPU needs to get ripped out for
several reasons:
1. It is obviously buggy. It uses mm->total_vm to judge the
task's footprint in the TLB. It should certainly be using
some measure of RSS, *NOT* ->total_vm since only resident
memory can populate the TLB.
2. Haswell, and several other CPUs are missing from the
intel_tlb_flushall_shift_set() function. Thus, it has been
demonstrated to bitrot quickly in practice.
3. It is plain wrong in my vm:
[ 0.037444] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
[ 0.037444] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0
[ 0.037444] tlb_flushall_shift: 6
Which leads to it to never use invlpg.
4. The assumptions about TLB refill costs are wrong:
http://lkml.kernel.org/r/1337782555-8088-3-git-send-email-alex.shi@intel.com
(more on this in later patches)
5. I can not reproduce the original data: https://lkml.org/lkml/2012/5/17/59
I believe the sample times were too short. Running the
benchmark in a loop yields times that vary quite a bit.
Note that this leaves us with a static ceiling of 1 page. This
is a conservative, dumb setting, and will be revised in a later
patch.
This also removes the code which attempts to predict whether we
are flushing data or instructions. We expect instruction flushes
to be relatively rare and not worth tuning for explicitly.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154055.ABC88E89@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
line of code is not exactly the easiest to audit, especially when
it ends up at two different indentation levels. This eliminates
one of the the copy-n-paste versions. It also gives us a unified
exit point for each path through this function. We need this in
a minute for our tracepoint.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154054.44F1CDDC@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Pull more perf updates from Ingo Molnar:
"A second round of perf updates:
- wide reaching kprobes sanitization and robustization, with the hope
of fixing all 'probe this function crashes the kernel' bugs, by
Masami Hiramatsu.
- uprobes updates from Oleg Nesterov: tmpfs support, corner case
fixes and robustization work.
- perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
et al:
* Add support to accumulate hist periods (Namhyung Kim)
* various fixes, refactorings and enhancements"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
perf: Differentiate exec() and non-exec() comm events
perf: Fix perf_event_comm() vs. exec() assumption
uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
perf/documentation: Add description for conditional branch filter
perf/x86: Add conditional branch filtering support
perf/tool: Add conditional branch filter 'cond' to perf record
perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
uprobes: Teach copy_insn() to support tmpfs
uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
perf/x86: Use common PMU interrupt disabled code
perf/ARM: Use common PMU interrupt disabled code
perf: Disable sampled events if no PMU interrupt
perf: Fix use after free in perf_remove_from_context()
perf tools: Fix 'make help' message error
perf record: Fix poll return value propagation
perf tools: Move elide bool into perf_hpp_fmt struct
perf tools: Remove elide setup for SORT_MODE__MEMORY mode
perf tools: Fix "==" into "=" in ui_browser__warning assignment
perf tools: Allow overriding sysfs and proc finding with env var
perf tools: Consider header files outside perf directory in tags target
...
If pagefault triggers due to SMEP triggering, it can't be really easily
distinguished from any other oops-causing pagefault, which might lead to quite
some confusion when trying to understand the reason for the oops.
Print an explanatory message in case the fault happened during instruction
fetch for _PAGE_USER page which is present and executable on SMEP-enabled CPUs.
This is consistent with what we are doing for NX already; in addition to
immediately seeing from the oops what might be happening, it can even easily
give a good indication to sysadmins who are carefully monitoring their kernel
logs that someone might be trying to pwn them.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1406102248490.1321@pobox.suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Pull x86 cdso updates from Peter Anvin:
"Vdso cleanups and improvements largely from Andy Lutomirski. This
makes the vdso a lot less ''special''"
* 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso, build: Make LE access macros clearer, host-safe
x86/vdso, build: Fix cross-compilation from big-endian architectures
x86/vdso, build: When vdso2c fails, unlink the output
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, mm: Replace arch_vma_name with vm_ops->name for vsyscalls
x86, mm: Improve _install_special_mapping and fix x86 vdso naming
mm, fs: Add vm_ops->name as an alternative to arch_vma_name
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated comments
x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSO
x86, vdso: Move the 32-bit vdso special pages after the text
x86, vdso: Reimplement vdso.so preparation in build-time C
x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c
x86, vdso: Clean up 32-bit vs 64-bit vdso params
x86, mm: Ensure correct alignment of the fixmap
Pull x86-64 espfix changes from Peter Anvin:
"This is the espfix64 code, which fixes the IRET information leak as
well as the associated functionality problem. With this code applied,
16-bit stack segments finally work as intended even on a 64-bit
kernel.
Consequently, this patchset also removes the runtime option that we
added as an interim measure.
To help the people working on Linux kernels for very small systems,
this patchset also makes these compile-time configurable features"
* 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option"
x86, espfix: Make it possible to disable 16-bit support
x86, espfix: Make espfix64 a Kconfig option, fix UML
x86, espfix: Fix broken header guard
x86, espfix: Move espfix definitions into a separate header file
x86-32, espfix: Remove filter for espfix32 due to race
x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
On system with 2TiB ram, current x86_64 have 128M as section size, and
one memory_block only include one section. So will have 16400 entries
under /sys/devices/system/memory/.
Current code try to use block id to find block pointer in /sys for any
section, and reuse that block pointer. that finding will take some time
even after commit 7c243c7168 ("mm: speedup in __early_pfn_to_nid")
that will skip the search in that case during booting up.
So solution could be increase block size just like SGI UV system did.
(harded code to 2g).
This patch is trying to probe the block size to make it match mmio remap
size. for example, Intel Nehalem later system will have memory range [0,
TOML), [4g, TOMH]. If the memory hole is 2g and total is 128g, TOM will
be 2g, and TOM2 will be 130g.
We could use 2g as block size instead of default 128M. That will reduce
number of entries in /sys/devices/system/memory/
On system 6TiB system will reduce boot time by 35 seconds.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
_PAGE_NUMA is currently an alias of _PROT_PROTNONE to trap NUMA hinting
faults on x86. Care is taken such that _PAGE_NUMA is used only in
situations where the VMA flags distinguish between NUMA hinting faults
and prot_none faults. This decision was x86-specific and conceptually
it is difficult requiring special casing to distinguish between PROTNONE
and NUMA ptes based on context.
Fundamentally, we only need the _PAGE_NUMA bit to tell the difference
between an entry that is really unmapped and a page that is protected
for NUMA hinting faults as if the PTE is not present then a fault will
be trapped.
Swap PTEs on x86-64 use the bits after _PAGE_GLOBAL for the offset.
This patch shrinks the maximum possible swap size and uses the bit to
uniquely distinguish between NUMA hinting ptes and swap ptes.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge x86/espfix into x86/vdso, due to changes in the vdso setup code
that otherwise cause conflicts.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Using arch_vma_name to give special mappings a name is awkward. x86
currently implements it by comparing the start address of the vma to
the expected address of the vdso. This requires tracking the start
address of special mappings and is probably buggy if a special vma
is split or moved.
Improve _install_special_mapping to just name the vma directly. Use
it to give the x86 vvar area a name, which should make CRIU's life
easier.
As a side effect, the vvar area will show up in core dumps. This
could be considered weird and is fixable.
[hpa: I say we accept this as-is but be prepared to deal with knocking
out the vvars from core dumps if this becomes a problem.]
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Currently, vdso.so files are prepared and analyzed by a combination
of objcopy, nm, some linker script tricks, and some simple ELF
parsers in the kernel. Replace all of that with plain C code that
runs at build time.
All five vdso images now generate .c files that are compiled and
linked in to the kernel image.
This should cause only one userspace-visible change: the loaded vDSO
images are stripped more heavily than they used to be. Everything
outside the loadable segment is dropped. In particular, this causes
the section table and section name strings to be missing. This
should be fine: real dynamic loaders don't load or inspect these
tables anyway. The result is roughly equivalent to eu-strip's
--strip-sections option.
The purpose of this change is to enable the vvar and hpet mappings
to be moved to the page following the vDSO load segment. Currently,
it is possible for the section table to extend into the page after
the load segment, so, if we map it, it risks overlapping the vvar or
hpet page. This happens whenever the load segment is just under a
multiple of PAGE_SIZE.
The only real subtlety here is that the old code had a C file with
inline assembler that did 'call VDSO32_vsyscall' and a linker script
that defined 'VDSO32_vsyscall = __kernel_vsyscall'. This most
likely worked by accident: the linker script entry defines a symbol
associated with an address as opposed to an alias for the real
dynamic symbol __kernel_vsyscall. That caused ld to relocate the
reference at link time instead of leaving an interposable dynamic
relocation. Since the VDSO32_vsyscall hack is no longer needed, I
now use 'call __kernel_vsyscall', and I added -Bsymbolic to make it
work. vdso2c will generate an error and abort the build if the
resulting image contains any dynamic relocations, so we won't
silently generate bad vdso images.
(Dynamic relocations are a problem because nothing will even attempt
to relocate the vdso.)
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2c4fcf45524162a34d87fdda1eb046b2a5cecee7.1399317206.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The early_ioremap code requires that its buffers not span a PMD
boundary. The logic for ensuring that only works if the fixmap is
aligned, so assert that it's aligned correctly.
To make this work reliably, reserve_top_address needs to be
adjusted.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/e59a5f4362661f75dd4841fa74e1f2448045e245.1399317206.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
In __ioremap_caller() (the guts of ioremap), we loop over the range of
pfns being remapped and checks each one individually with page_is_ram().
For large ioremaps, this can be very slow. For example, we have a
device with a 256 GiB PCI BAR, and ioremapping this BAR can take 20+
seconds -- sometimes long enough to trigger the soft lockup detector!
Internally, page_is_ram() calls walk_system_ram_range() on a single
page. Instead, we can make a single call to walk_system_ram_range()
from __ioremap_caller(), and do our further checks only for any RAM
pages that we find. For the common case of MMIO, this saves an enormous
amount of work, since the range being ioremapped doesn't intersect
system RAM at all.
With this change, ioremap on our 256 GiB BAR takes less than 1 second.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Link: http://lkml.kernel.org/r/1399054721-1331-1-git-send-email-roland@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer. This
causes some 16-bit software to break, but it also leaks kernel state
to user space. We have a software workaround for that ("espfix") for
the 32-bit kernel, but it relies on a nonzero stack segment base which
is not available in 64-bit mode.
In checkin:
b3b42ac2cb x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels
we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.
This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart. When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace. The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.
(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)
Special thanks to:
- Andy Lutomirski, for the suggestion of using very small stack slots
and copy (as opposed to map) the IRET frame there, and for the
suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.
Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Lutomriski <amluto@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dirk Hohndel <dirk@hohndel.org>
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: comex <comexk@gmail.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org> # consider after upstream merge
Use NOKPROBE_SYMBOL macro for protecting functions
from kprobes instead of __kprobes annotation under
arch/x86.
This applies nokprobe_inline annotation for some cases,
because NOKPROBE_SYMBOL() will inhibit inlining by
referring the symbol address.
This just folds a bunch of previous NOKPROBE_SYMBOL()
cleanup patches for x86 to one patch.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20140417081814.26341.51656.stgit@ltc230.yrl.intra.hitachi.co.jp
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We use the accessed bit to age a page at page reclaim time,
and currently we also flush the TLB when doing so.
But in some workloads TLB flush overhead is very heavy. In my
simple multithreaded app with a lot of swap to several pcie
SSDs, removing the tlb flush gives about 20% ~ 30% swapout
speedup.
Fortunately just removing the TLB flush is a valid optimization:
on x86 CPUs, clearing the accessed bit without a TLB flush
doesn't cause data corruption.
It could cause incorrect page aging and the (mistaken) reclaim of
hot pages, but the chance of that should be relatively low.
So as a performance optimization don't flush the TLB when
clearing the accessed bit, it will eventually be flushed by
a context switch or a VM operation anyway. [ In the rare
event of it not getting flushed for a long time the delay
shouldn't really matter because there's no real memory
pressure for swapout to react to. ]
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-mm@kvack.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140408075809.GA1764@kernel.org
[ Rewrote the changelog and the code comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Kmemcheck should use the preferred interface for parsing command line
arguments, kstrto*(), rather than sscanf() itself. Use it
appropriately.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move x86 over to the generic early ioremap implementation.
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series takes the common bits from the x86 early ioremap
implementation and creates a generic implementation which may be used by
other architectures. The early ioremap interfaces are intended for
situations where boot code needs to make temporary virtual mappings
before the normal ioremap interfaces are available. Typically, this
means before paging_init() has run.
This patch (of 6):
There's a lot of sparse warnings for code like below: void *a =
early_memremap(phys_addr, size);
early_memremap intend to map kernel memory with ioremap facility, the
return pointer should be a kernel ram pointer instead of iomem one.
For making the function clearer and supressing sparse warnings this patch
do below two things:
1. cast to (__force void *) for the return value of early_memremap
2. add early_memunmap function and pass (__force void __iomem *) to iounmap
From Boris:
"Ingo told me yesterday, it makes sense too. I'd guess we can try it.
FWIW, all callers of early_memremap use the memory they get remapped
as normal memory so we should be safe"
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 old platform removal from Peter Anvin:
"This patchset removes support for several completely obsolete
platforms, where the maintainers either have completely vanished or
acked the removal. For some of them it is questionable if there even
exists functional specimens of the hardware"
Geert Uytterhoeven apparently thought this was a April Fool's pull request ;)
* 'x86-nuke-platforms-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, platforms: Remove NUMAQ
x86, platforms: Remove SGI Visual Workstation
x86, apic: Remove support for IBM Summit/EXA chipset
x86, apic: Remove support for ia32-based Unisys ES7000
Pull x86 mm change from Ingo Molnar:
"A micro-optimization for acpi_numa_slit_init()"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Avoid duplicated pxm_to_node() calls
Pull x86 EFI changes from Ingo Molnar:
"The main changes:
- Add debug code to the dump EFI pagetable - Borislav Petkov
- Make 1:1 runtime mapping robust when booting on machines with lots
of memory - Borislav Petkov
- Move the EFI facilities bits out of 'x86_efi_facility' and into
efi.flags which is the standard architecture independent place to
keep EFI state, by Matt Fleming.
- Add 'EFI mixed mode' support: this allows 64-bit kernels to be
booted from 32-bit firmware. This needs a bootloader that supports
the 'EFI handover protocol'. By Matt Fleming"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
x86, efi: Abstract x86 efi_early calls
x86/efi: Restore 'attr' argument to query_variable_info()
x86/efi: Rip out phys_efi_get_time()
x86/efi: Preserve segment registers in mixed mode
x86/boot: Fix non-EFI build
x86, tools: Fix up compiler warnings
x86/efi: Re-disable interrupts after calling firmware services
x86/boot: Don't overwrite cr4 when enabling PAE
x86/efi: Wire up CONFIG_EFI_MIXED
x86/efi: Add mixed runtime services support
x86/efi: Firmware agnostic handover entry points
x86/efi: Split the boot stub into 32/64 code paths
x86/efi: Add early thunk code to go from 64-bit to 32-bit
x86/efi: Build our own EFI services pointer table
efi: Add separate 32-bit/64-bit definitions
x86/efi: Delete dead code when checking for non-native
x86/mm/pageattr: Always dump the right page table in an oops
x86, tools: Consolidate #ifdef code
x86/boot: Cleanup header.S by removing some #ifdefs
efi: Use NULL instead of 0 for pointer
...
Pull x86 cpu handling changes from Ingo Molnar:
"Bigger changes:
- Intel CPU hardware-enablement: new vector instructions support
(AVX-512), by Fenghua Yu.
- Support the clflushopt instruction and use it in appropriate
places. clflushopt is similar to clflush but with more relaxed
ordering, by Ross Zwisler.
- MSR accessor cleanups, by Borislav Petkov.
- 'forcepae' boot flag for those who have way too much time to spend
on way too old Pentium-M systems and want to live way too
dangerously, by Chris Bainbridge"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, cpu: Add forcepae parameter for booting PAE kernels on PAE-disabled Pentium M
Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC
x86, intel: Make MSR_IA32_MISC_ENABLE bit constants systematic
x86, Intel: Convert to the new bit access MSR accessors
x86, AMD: Convert to the new bit access MSR accessors
x86: Add another set of MSR accessor functions
x86: Use clflushopt in drm_clflush_virt_range
x86: Use clflushopt in drm_clflush_page
x86: Use clflushopt in clflush_cache_range
x86: Add support for the clflushopt instruction
x86, AVX-512: Enable AVX-512 States Context Switch
x86, AVX-512: AVX-512 Feature Detection
Building on commit 0ac09f9f8c ("x86, trace: Fix CR2 corruption when
tracing page faults") this patch addresses another few issues:
- Now that read_cr2() is lifted into trace_do_page_fault(), we should
pass the address to trace_page_fault_entries() to avoid it
re-reading a potentially changed cr2.
- Put both trace_do_page_fault() and trace_page_fault_entries() under
CONFIG_TRACING.
- Mark both fault entry functions {,trace_}do_page_fault() as notrace
to avoid getting __mcount or other function entry trace callbacks
before we've observed CR2.
- Mark __do_page_fault() as noinline to guarantee the function tracer
does get to see the fault.
Cc: <jolsa@redhat.com>
Cc: <vincent.weaver@maine.edu>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140306145300.GO9987@twins.programming.kicks-ass.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The trace_do_page_fault function trigger tracepoint
and then handles the actual page fault.
This could lead to error if the tracepoint caused page
fault. The original cr2 value gets lost and the original
page fault handler kills current process with SIGSEGV.
This happens if you record page faults with callchain
data, the user part of it will cause tracepoint handler
to page fault:
# perf record -g -e exceptions:page_fault_user ls
Fixing this by saving the original cr2 value
and using it after tracepoint handler is done.
v2: Moving the cr2 read before exception_enter, because
it could trigger tracepoint as well.
Reported-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1402211701380.6395@vincent-weaver-1.um.maine.edu
Link: http://lkml.kernel.org/r/20140228160526.GD1133@krava.brq.redhat.com
Now that we have EFI-specific page tables we need to lookup the pgd when
dumping those page tables, rather than assuming that swapper_pgdir is
the current pgdir.
Remove the double underscore prefix, which is usually reserved for
static functions.
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
We will use it in efi so expose it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
With reusing the ->trampoline_pgd page table for mapping EFI regions in
order to use them after having switched to EFI virtual mode, it is very
useful to be able to dump aforementioned page table in dmesg. This adds
that functionality through the walk_pgd_level() interface which can be
called from somewhere else.
The original functionality of dumping to debugfs remains untouched.
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The NUMAQ support seems to be unmaintained, remove it.
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/n/530CFD6C.7040705@zytor.com
If CONFIG_X86_SMAP is disabled, smap_violation() tests for conditions
which are incorrect (as the AC flag doesn't matter), causing spurious
faults.
The dynamic disabling of SMAP (nosmap on the command line) is fine
because it disables X86_FEATURE_SMAP, therefore causing the
static_cpu_has() to return false.
Found by Fengguang Wu's test system.
[ v3: move all predicates into smap_violation() ]
[ v2: use IS_ENABLED() instead of #ifdef ]
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Link: http://lkml.kernel.org/r/20140213124550.GA30497@localhost
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v3.7+
In slit init code, too many pxm_to_node() function calls are done.
We can store from_node/to_node instead of keep calling
pxm_to_node().
- Before this patch: pxm_to_node() is called n*(1+n*3) times.
- After this patch: pxm_to_node() is called n*(1+n) times.
for 8 sockets, it will be 72 instead of 200.
for 32 sockets, it will be 1056 instead of 3104.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1390770102-4007-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 fixes from Peter Anvin:
"Quite a varied little collection of fixes. Most of them are
relatively small or isolated; the biggest one is Mel Gorman's fixes
for TLB range flushing.
A couple of AMD-related fixes (including not crashing when given an
invalid microcode image) and fix a crash when compiled with gcov"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, microcode, AMD: Unify valid container checks
x86, hweight: Fix BUG when booting with CONFIG_GCOV_PROFILE_ALL=y
x86/efi: Allow mapping BGRT on x86-32
x86: Fix the initialization of physnode_map
x86, cpu hotplug: Fix stack frame warning in check_irq_vectors_for_cpu_disable()
x86/intel/mid: Fix X86_INTEL_MID dependencies
arch/x86/mm/srat: Skip NUMA_NO_NODE while parsing SLIT
mm, x86: Revisit tlb_flushall_shift tuning for page flushes except on IvyBridge
x86: mm: change tlb_flushall_shift for IvyBridge
x86/mm: Eliminate redundant page table walk during TLB range flushing
x86/mm: Clean up inconsistencies when flushing TLB ranges
mm, x86: Account for TLB flushes only when debugging
x86/AMD/NB: Fix amd_set_subcaches() parameter type
x86/quirks: Add workaround for AMD F16h Erratum792
x86, doc, kconfig: Fix dud URL for Microcode data
The following path will cause array out of bound.
memblock_add_region() will always set nid in memblock.reserved to
MAX_NUMNODES. In numa_register_memblks(), after we set all nid to
correct valus in memblock.reserved, we called setup_node_data(), and
used memblock_alloc_nid() to allocate memory, with nid set to
MAX_NUMNODES.
The nodemask_t type can be seen as a bit array. And the index is 0 ~
MAX_NUMNODES-1.
After that, when we call node_set() in numa_clear_kernel_node_hotplug(),
the nodemask_t got an index of value MAX_NUMNODES, which is out of [0 ~
MAX_NUMNODES-1].
See below:
numa_init()
|---> numa_register_memblks()
| |---> memblock_set_node(memory) set correct nid in memblock.memory
| |---> memblock_set_node(reserved) set correct nid in memblock.reserved
| |......
| |---> setup_node_data()
| |---> memblock_alloc_nid() here, nid is set to MAX_NUMNODES (1024)
|......
|---> numa_clear_kernel_node_hotplug()
|---> node_set() here, we have an index 1024, and overflowed
This patch moves nid setting to numa_clear_kernel_node_hotplug() to fix
this problem.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Tested-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reported-by: Dave Jones <davej@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Tested-by: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On-stack variable numa_kernel_nodes in numa_clear_kernel_node_hotplug()
was not initialized. So we need to initialize it.
[akpm@linux-foundation.org: use NODE_MASK_NONE, per David]
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Tested-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: David Rientjes <rientjes@google.com>
Tested-by: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With DISCONTIGMEM, the mapping between a pfn and its owning node is
initialized using data provided by the BIOS. However, the initialization
may fail if the extents are not aligned to section boundary (64M).
The symptom of this bug is an early boot failure in pfn_to_page(),
as it tries to access NODE_DATA(__nid) using index from an unitialized
element of the physnode_map[] array.
While the bug is always present, it is more likely to be hit in kdump
kernels on large machines, because:
1. The memory map for a kdump kernel is specified as exactmap, and
exactmap is more likely to be unaligned.
2. Large reservations are more likely to span across a 64M boundary.
[ hpa: fixed incorrect use of "pfn" instead of "start" ]
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Link: http://lkml.kernel.org/r/20140201133019.32e56f86@hananiah.suse.cz
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
When ACPI SLIT table has an I/O locality (i.e. a locality
unique to an I/O device), numa_set_distance() emits this warning
message:
NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10
acpi_numa_slit_init() calls numa_set_distance() with
pxm_to_node(), which assumes that all localities have been
parsed with SRAT previously. SRAT does not list I/O localities,
where as SLIT lists all localities including I/Os. Hence,
pxm_to_node() returns NUMA_NO_NODE (-1) for an I/O locality.
I/O localities are not supported and are ignored today, but emitting
such warning message leads to unnecessary confusion.
Change acpi_numa_slit_init() to avoid calling
numa_set_distance() with NUMA_NO_NODE.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/n/tip-dSvpjjvp8aMzs1ybkftxohlh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When choosing between doing an address space or ranged flush,
the x86 implementation of flush_tlb_mm_range takes into account
whether there are any large pages in the range. A per-page
flush typically requires fewer entries than would covered by a
single large page and the check is redundant.
There is one potential exception. THP migration flushes single
THP entries and it conceivably would benefit from flushing a
single entry instead of the mm. However, this flush is after a
THP allocation, copy and page table update potentially with any
other threads serialised behind it. In comparison to that, the
flush is noise. It makes more sense to optimise balancing to
require fewer flushes than to optimise the flush itself.
This patch deletes the redundant huge page check.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Davidlohr Bueso <davidlohr@hp.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-sgei1drpOcburujPsfh6ovmo@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
NR_TLB_LOCAL_FLUSH_ALL is not always accounted for correctly and
the comparison with total_vm is done before taking
tlb_flushall_shift into account. Clean it up.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Davidlohr Bueso <davidlohr@hp.com>
Reviewed-by: Alex Shi <alex.shi@linaro.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/n/tip-Iz5gcahrgskIldvukulzi0hh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Bisection between 3.11 and 3.12 fingered commit 9824cf97 ("mm:
vmstats: tlb flush counters") to cause overhead problems.
The counters are undeniably useful but how often do we really
need to debug TLB flush related issues? It does not justify
taking the penalty everywhere so make it a debugging option.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Davidlohr Bueso <davidlohr@hp.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-XzxjntugxuwpxXhcrxqqh53b@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Most of the VM_BUG_ON assertions are performed on a page. Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.
I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.
This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.
[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update X86 code to use NUMA_NO_NODE instead of MAX_NUMNODES while
calling memblock APIs, because memblock API will be changed to use
NUMA_NO_NODE and will produce warning during boot otherwise.
See:
https://lkml.org/lkml/2013/12/9/898
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At very early time, the kernel have to use some memory such as loading
the kernel image. We cannot prevent this anyway. So any node the
kernel resides in should be un-hotpluggable.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Rafael J . Wysocki" <rjw@sisk.pl>
Cc: Chen Tang <imtangchen@gmail.com>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Liu Jiang <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 kernel address space randomization support from Peter Anvin:
"This enables kernel address space randomization for x86"
* 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, kaslr: Clarify RANDOMIZE_BASE_MAX_OFFSET
x86, kaslr: Remove unused including <linux/version.h>
x86, kaslr: Use char array to gain sizeof sanity
x86, kaslr: Add a circular multiply for better bit diffusion
x86, kaslr: Mix entropy sources together as needed
x86/relocs: Add percpu fixup for GNU ld 2.23
x86, boot: Rename get_flags() and check_flags() to *_cpuflags()
x86, kaslr: Raise the maximum virtual address to -1 GiB on x86_64
x86, kaslr: Report kernel offset on panic
x86, kaslr: Select random position from e820 maps
x86, kaslr: Provide randomness functions
x86, kaslr: Return location from decompress_kernel
x86, boot: Move CPU flags out of cpucheck
x86, relocs: Add more per-cpu gold special cases
Pull x86 mm changes from Ingo Molnar:
"A cleanup, a fix and ASLR support for hugetlb mappings"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/numa: Fix 32-bit kernel NUMA boot
x86/mm: Implement ASLR for hugetlb mappings
x86/mm: Unify pte_to_pgoff() and pgoff_to_pte() helpers
Pull x86 EFI changes from Ingo Molnar:
"This consists of two main parts:
- New static EFI runtime services virtual mapping layout which is
groundwork for kexec support on EFI (Borislav Petkov)
- EFI kexec support itself (Dave Young)"
* 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/efi: parse_efi_setup() build fix
x86: ksysfs.c build fix
x86/efi: Delete superfluous global variables
x86: Reserve setup_data ranges late after parsing memmap cmdline
x86: Export x86 boot_params to sysfs
x86: Add xloadflags bit for EFI runtime support on kexec
x86/efi: Pass necessary EFI data for kexec via setup_data
efi: Export EFI runtime memory mapping to sysfs
efi: Export more EFI table variables to sysfs
x86/efi: Cleanup efi_enter_virtual_mode() function
x86/efi: Fix off-by-one bug in EFI Boot Services reservation
x86/efi: Add a wrapper function efi_map_region_fixed()
x86/efi: Remove unused variables in __map_region()
x86/efi: Check krealloc return value
x86/efi: Runtime services virtual mapping
x86/mm/cpa: Map in an arbitrary pgd
x86/mm/pageattr: Add last levels of error path
x86/mm/pageattr: Add a PUD error unwinding path
x86/mm/pageattr: Add a PTE pagetable populating function
x86/mm/pageattr: Add a PMD pagetable populating function
...
Pull x86 cleanups from Ingo Molnar:
"Misc cleanups"
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, cpu, amd: Fix a shadowed variable situation
um, x86: Fix vDSO build
x86: Delete non-required instances of include <linux/init.h>
x86, realmode: Pointer walk cleanups, pull out invariant use of __pa()
x86/traps: Clean up error exception handler definitions
Waiman managed to trigger a PMI while in a emulate_vsyscall() fault,
the PMI in turn managed to trigger a fault while obtaining a stack
trace. This triggered the sig_on_uaccess_error recursive fault logic
and killed the process dead.
Fix this by explicitly excluding interrupts from the recursive fault
logic.
Reported-and-Tested-by: Waiman Long <waiman.long@hp.com>
Fixes: e00b12e64b ("perf/x86: Further optimize copy_from_user_nmi()")
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140110200603.GJ7572@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>. Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.
[ hpa: undid incorrect removal from arch/x86/kernel/head_32.S ]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: http://lkml.kernel.org/r/1389054026-12947-1-git-send-email-paul.gortmaker@windriver.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
When booting a 32-bit x86 kernel on a NUMA machine, node data
cannot be allocated from local node if the account of memory for
node 0 covers the low memory space entirely:
[ 0.000000] Initmem setup node 0 [mem 0x00000000-0x83fffffff]
[ 0.000000] NODE_DATA [mem 0x367ed000-0x367edfff]
[ 0.000000] Initmem setup node 1 [mem 0x840000000-0xfffffffff]
[ 0.000000] Cannot find 4096 bytes in node 1
[ 0.000000] 64664MB HIGHMEM available.
[ 0.000000] 871MB LOWMEM available.
To fix this issue, node data is allowed to be allocated from
other nodes if the memory of local node is still not mapped. The
expected result looks like this:
[ 0.000000] Initmem setup node 0 [mem 0x00000000-0x83fffffff]
[ 0.000000] NODE_DATA [mem 0x367ed000-0x367edfff]
[ 0.000000] Initmem setup node 1 [mem 0x840000000-0xfffffffff]
[ 0.000000] NODE_DATA [mem 0x367ec000-0x367ecfff]
[ 0.000000] NODE_DATA(1) on node 0
[ 0.000000] 64664MB HIGHMEM available.
[ 0.000000] 871MB LOWMEM available.
Signed-off-by: Lans Zhang <jia.zhang@windriver.com>
Cc: <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1386303510-18574-1-git-send-email-jia.zhang@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Base pages are unmapped and flushed from cache and TLB during normal
page migration and replaced with a migration entry that causes any
parallel NUMA hinting fault or gup to block until migration completes.
THP does not unmap pages due to a lack of support for migration entries
at a PMD level. This allows races with get_user_pages and
get_user_pages_fast which commit 3f926ab945 ("mm: Close races between
THP migration and PMD numa clearing") made worse by introducing a
pmd_clear_flush().
This patch forces get_user_page (fast and normal) on a pmd_numa page to
go through the slow get_user_page path where it will serialise against
THP migration and properly account for the NUMA hinting fault. On the
migration side the page table lock is taken for each PTE update.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
groundwork for kexec support on EFI - Borislav Petkov
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi
Pull EFI virtual mapping changes from Matt Fleming:
* New static EFI runtime services virtual mapping layout which is
groundwork for kexec support on EFI. (Borislav Petkov)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two code paths how page with pmd page table can be freed:
pmd_free() and pmd_free_tlb().
I've missed the second one and didn't add page table destructor call
there. It leads to leak of page->ptl for pmd page tables, if
dynamically allocated page->ptl is in use.
The patch adds the missed destructor and modifies documentation
accordingly.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Andrey Vagin <avagin@openvz.org>
Tested-by: Andrey Vagin <avagin@openvz.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Note that pmds[i] is simply uninitialized at that point...
Granted, it's very hard to hit (you need split page locks *and*
kmalloc(sizeof(spinlock_t), GFP_KERNEL) failing), but the code is
obviously bogus.
Introduced by commit 09ef493985 ("x86: add missed
pgtable_pmd_page_ctor/dtor calls for preallocated pmds")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew noticed that hugetlb mappings don't participate in ASLR on x86-64:
% for i in `seq 3`; do
> tools/testing/selftests/vm/map_hugetlb | grep address
> done
Returned address is 0x2aaaaac00000
Returned address is 0x2aaaaac00000
Returned address is 0x2aaaaac00000
/proc/PID/maps entries for the mapping are always the same
(except inode number):
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 8200 /anon_hugepage (deleted)
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 256 /anon_hugepage (deleted)
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 7180 /anon_hugepage (deleted)
The reason is the generic hugetlb_get_unmapped_area() function
which is used on x86-64. It doesn't support randomization and
use bottom-up unmapped area lookup, instead of usual top-down
on x86-64.
x86 has arch-specific hugetlb_get_unmapped_area(), but it's used
only on x86-32.
Let's use arch-specific hugetlb_get_unmapped_area() on x86-64
too. That adds ASLR and switches hugetlb mappings to use top-down
unmapped area lookup:
% for i in `seq 3`; do
> tools/testing/selftests/vm/map_hugetlb | grep address
> done
Returned address is 0x7f4f08a00000
Returned address is 0x7fdda4200000
Returned address is 0x7febe0000000
/proc/PID/maps entries:
7f4f08a00000-7f4f18a00000 rw-p 00000000 00:0c 1168 /anon_hugepage (deleted)
7fdda4200000-7fddb4200000 rw-p 00000000 00:0c 7092 /anon_hugepage (deleted)
7febe0000000-7febf0000000 rw-p 00000000 00:0c 7183 /anon_hugepage (deleted)
Unmapped area lookup policy for hugetlb mappings is consistent
with normal mappings now -- the only difference is alignment
requirements for huge pages.
libhugetlbfs test-suite didn't detect any regressions with the
patch applied (although it shows few failures on my machine
regardless the patch).
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mgorman@suse.de>
Link: http://lkml.kernel.org/r/20131119131750.EA45CE0090@blue.fi.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In split page table lock case, we embed spinlock_t into struct page.
For obvious reason, we don't want to increase size of struct page if
spinlock_t is too big, like with DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC or
on -rt kernel. So we disable split page table lock, if spinlock_t is
too big.
This patchset allows to allocate the lock dynamically if spinlock_t is
big. In this page->ptl is used to store pointer to spinlock instead of
spinlock itself. It costs additional cache line for indirect access,
but fix page fault scalability for multi-threaded applications.
LOCK_STAT depends on DEBUG_SPINLOCK, so on current kernel enabling
LOCK_STAT to analyse scalability issues breaks scalability. ;)
The patchset mostly fixes this. Results for ./thp_memscale -c 80 -b 512M
on 4-socket machine:
baseline, no CONFIG_LOCK_STAT: 9.115460703 seconds time elapsed
baseline, CONFIG_LOCK_STAT=y: 53.890567123 seconds time elapsed
patched, no CONFIG_LOCK_STAT: 8.852250368 seconds time elapsed
patched, CONFIG_LOCK_STAT=y: 11.069770759 seconds time elapsed
Patch count is scary, but most of them trivial. Overview:
Patches 1-4 Few bug fixes. No dependencies to other patches.
Probably should applied as soon as possible.
Patch 5 Changes signature of pgtable_page_ctor(). We will use it
for dynamic lock allocation, so it can fail.
Patches 6-8 Add missing constructor/destructor calls on few archs.
It's fixes NR_PAGETABLE accounting and prepare to use
split ptl.
Patches 9-33 Add pgtable_page_ctor() fail handling to all archs.
Patches 34 Finally adds support of dynamically-allocated page->pte.
Also contains documentation for split page table lock.
This patch (of 34):
I've missed that we preallocate few pmds on pgd_alloc() if X86_PAE
enabled. Let's add missed constructor/destructor calls.
I haven't noticed it during testing since prep_new_page() clears
page->mapping and therefore page->ptl. It's effectively equal to
spin_lock_init(&page->ptl).
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
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>
Pull two x86 fixes from Ingo Molnar.
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode/amd: Tone down printk(), don't treat a missing firmware file as an error
x86/dumpstack: Fix printk_address for direct addresses
Pull x86/trace changes from Ingo Molnar:
"This adds page fault tracepoints which have zero runtime cost in the
disabled case via IDT trickery (no NOPs in the page fault hotpath)"
* 'x86-trace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, trace: Change user|kernel_page_fault to page_fault_user|kernel
x86, trace: Add page fault tracepoints
x86, trace: Delete __trace_alloc_intr_gate()
x86, trace: Register exception handler to trace IDT
x86, trace: Remove __alloc_intr_gate()
The hot-Pluggable field in SRAT specifies which memory is hotpluggable.
As we mentioned before, if hotpluggable memory is used by the kernel, it
cannot be hot-removed. So memory hotplug users may want to set all
hotpluggable memory in ZONE_MOVABLE so that the kernel won't use it.
Memory hotplug users may also set a node as movable node, which has
ZONE_MOVABLE only, so that the whole node can be hot-removed.
But the kernel cannot use memory in ZONE_MOVABLE. By doing this, the
kernel cannot use memory in movable nodes. This will cause NUMA
performance down. And other users may be unhappy.
So we need a way to allow users to enable and disable this functionality.
In this patch, we introduce movable_node boot option to allow users to
choose to not to consume hotpluggable memory at early boot time and later
we can set it as ZONE_MOVABLE.
To achieve this, the movable_node boot option will control the memblock
allocation direction. That said, after memblock is ready, before SRAT is
parsed, we should allocate memory near the kernel image as we explained in
the previous patches. So if movable_node boot option is set, the kernel
does the following:
1. After memblock is ready, make memblock allocate memory bottom up.
2. After SRAT is parsed, make memblock behave as default, allocate memory
top down.
Users can specify "movable_node" in kernel commandline to enable this
functionality. For those who don't use memory hotplug or who don't want
to lose their NUMA performance, just don't specify anything. The kernel
will work as before.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Suggested-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Linux kernel cannot migrate pages used by the kernel. As a result,
kernel pages cannot be hot-removed. So we cannot allocate hotpluggable
memory for the kernel.
In a memory hotplug system, any numa node the kernel resides in should be
unhotpluggable. And for a modern server, each node could have at least
16GB memory. So memory around the kernel image is highly likely
unhotpluggable.
ACPI SRAT (System Resource Affinity Table) contains the memory hotplug
info. But before SRAT is parsed, memblock has already started to allocate
memory for the kernel. So we need to prevent memblock from doing this.
So direct memory mapping page tables setup is the case.
init_mem_mapping() is called before SRAT is parsed. To prevent page
tables being allocated within hotpluggable memory, we will use bottom-up
direction to allocate page tables from the end of kernel image to the
higher memory.
Note:
As for allocating page tables in lower memory, TJ said:
: This is an optional behavior which is triggered by a very specific kernel
: boot param, which I suspect is gonna need to stick around to support
: memory hotplug in the current setup unless we add another layer of address
: translation to support memory hotplug.
As for page tables may occupy too much lower memory if using 4K mapping
(CONFIG_DEBUG_PAGEALLOC and CONFIG_KMEMCHECK both disable using >4k
pages), TJ said:
: But as I said in the same paragraph, parsing SRAT earlier doesn't solve
: the problem in itself either. Ignoring the option if 4k mapping is
: required and memory consumption would be prohibitive should work, no?
: Something like that would be necessary if we're gonna worry about cases
: like this no matter how we implement it, but, frankly, I'm not sure this
: is something worth worrying about.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Create a new function memory_map_top_down to factor out of the top-down
direct memory mapping pagetable setup. This is also a preparation for the
following patch, which will introduce the bottom-up memory mapping. That
said, we will put the two ways of pagetable setup into separate functions,
and choose to use which way in init_mem_mapping, which makes the code more
clear.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Consider a kernel crash in a module, simulated the following way:
static int my_init(void)
{
char *map = (void *)0x5;
*map = 3;
return 0;
}
module_init(my_init);
When we turn off FRAME_POINTERs, the very first instruction in
that function causes a BUG. The problem is that we print IP in
the BUG report using %pB (from printk_address). And %pB
decrements the pointer by one to fix printing addresses of
functions with tail calls.
This was added in commit 71f9e59800 ("x86, dumpstack: Use
%pB format specifier for stack trace") to fix the call stack
printouts.
So instead of correct output:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa01ac000>] my_init+0x0/0x10 [pb173]
We get:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa0152000>] 0xffffffffa0151fff
To fix that, we use %pS only for stack addresses printouts (via
newly added printk_stack_address) and %pB for regs->ip (via
printk_address). I.e. we revert to the old behaviour for all
except call stacks. And since from all those reliable is 1, we
remove that parameter from printk_address.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: joe@perches.com
Cc: jirislaby@gmail.com
Link: http://lkml.kernel.org/r/1382706418-8435-1-git-send-email-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 mm fixlet from Ingo Molnar:
"One cleanup that documents a particular detail in init_mem_mapping()"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Add 'step_size' comments to init_mem_mapping()
Tracepoints are named hierachially, and it makes more sense to keep a
general flow of information level from general to specific from left
to right, i.e.
x86_exceptions.page_fault_user|kernel
rather than
x86_exceptions.user|kernel_page_fault
Suggested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20131111082955.GB12405@gmail.com
