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Author SHA1 Message Date
Michal Hocko
2f064f3485 mm: make page pfmemalloc check more robust 
Commit c48a11c7ad ("netvm: propagate page->pfmemalloc to skb") added
checks for page->pfmemalloc to __skb_fill_page_desc():

        if (page->pfmemalloc && !page->mapping)
                skb->pfmemalloc = true;

It assumes page->mapping == NULL implies that page->pfmemalloc can be
trusted.  However, __delete_from_page_cache() can set set page->mapping
to NULL and leave page->index value alone.  Due to being in union, a
non-zero page->index will be interpreted as true page->pfmemalloc.

So the assumption is invalid if the networking code can see such a page.
And it seems it can.  We have encountered this with a NFS over loopback
setup when such a page is attached to a new skbuf.  There is no copying
going on in this case so the page confuses __skb_fill_page_desc which
interprets the index as pfmemalloc flag and the network stack drops
packets that have been allocated using the reserves unless they are to
be queued on sockets handling the swapping which is the case here and
that leads to hangs when the nfs client waits for a response from the
server which has been dropped and thus never arrive.

The struct page is already heavily packed so rather than finding another
hole to put it in, let's do a trick instead.  We can reuse the index
again but define it to an impossible value (-1UL).  This is the page
index so it should never see the value that large.  Replace all direct
users of page->pfmemalloc by page_is_pfmemalloc which will hide this
nastiness from unspoiled eyes.

The information will get lost if somebody wants to use page->index
obviously but that was the case before and the original code expected
that the information should be persisted somewhere else if that is
really needed (e.g.  what SLAB and SLUB do).

[akpm@linux-foundation.org: fix blooper in slub]
Fixes: c48a11c7ad ("netvm: propagate page->pfmemalloc to skb")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Debugged-by: Vlastimil Babka <vbabka@suse.com>
Debugged-by: Jiri Bohac <jbohac@suse.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>	[3.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-21 14:30:10 -07:00
Xishi Qiu
f9126ab924 memory-hotplug: fix wrong edge when hot add a new node 
When we add a new node, the edge of memory may be wrong.

e.g. system has 4 nodes, and node3 is movable, node3 mem:[24G-32G],

1. hotremove the node3,
2. then hotadd node3 with a part of memory, mem:[26G-30G],
3. call hotadd_new_pgdat()
        free_area_init_node()
                get_pfn_range_for_nid()
4. it will return wrong start_pfn and end_pfn, because we have not
update the memblock.

This patch also fixes a BUG_ON during hot-addition, please see
http://marc.info/?l=linux-kernel&m=142961156129456&w=2

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-14 15:56:32 -07:00
Naoya Horiguchi
f4c18e6f7b mm: check __PG_HWPOISON separately from PAGE_FLAGS_CHECK_AT_* 
The race condition addressed in commit add05cecef ("mm: soft-offline:
don't free target page in successful page migration") was not closed
completely, because that can happen not only for soft-offline, but also
for hard-offline.  Consider that a slab page is about to be freed into
buddy pool, and then an uncorrected memory error hits the page just
after entering __free_one_page(), then VM_BUG_ON_PAGE(page->flags &
PAGE_FLAGS_CHECK_AT_PREP) is triggered, despite the fact that it's not
necessary because the data on the affected page is not consumed.

To solve it, this patch drops __PG_HWPOISON from page flag checks at
allocation/free time.  I think it's justified because __PG_HWPOISON
flags is defined to prevent the page from being reused, and setting it
outside the page's alloc-free cycle is a designed behavior (not a bug.)

For recent months, I was annoyed about BUG_ON when soft-offlined page
remains on lru cache list for a while, which is avoided by calling
put_page() instead of putback_lru_page() in page migration's success
path.  This means that this patch reverts a major change from commit
add05cecef about the new refcounting rule of soft-offlined pages, so
"reuse window" revives.  This will be closed by a subsequent patch.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-07 04:39:42 +03:00
Mel Gorman
4248b0da46 fs, file table: reinit files_stat.max_files after deferred memory initialisation 
Dave Hansen reported the following;

	My laptop has been behaving strangely with 4.2-rc2.  Once I log
	in to my X session, I start getting all kinds of strange errors
	from applications and see this in my dmesg:

        	VFS: file-max limit 8192 reached

The problem is that the file-max is calculated before memory is fully
initialised and miscalculates how much memory the kernel is using.  This
patch recalculates file-max after deferred memory initialisation.  Note
that using memory hotplug infrastructure would not have avoided this
problem as the value is not recalculated after memory hot-add.

4.1:             files_stat.max_files = 6582781
4.2-rc2:         files_stat.max_files = 8192
4.2-rc2 patched: files_stat.max_files = 6562467

Small differences with the patch applied and 4.1 but not enough to matter.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Dave Hansen <dave.hansen@intel.com>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Alex Ng <alexng@microsoft.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-07 04:39:40 +03:00
Nicolai Stange
d3cd131d93 mm, meminit: replace rwsem with completion 
Commit 0e1cc95b4c ("mm: meminit: finish initialisation of struct pages
before basic setup") introduced a rwsem to signal completion of the
initialization workers.

Lockdep complains about possible recursive locking:
  =============================================
  [ INFO: possible recursive locking detected ]
  4.1.0-12802-g1dc51b8 #3 Not tainted
  ---------------------------------------------
  swapper/0/1 is trying to acquire lock:
  (pgdat_init_rwsem){++++.+},
    at: [<ffffffff8424c7fb>] page_alloc_init_late+0xc7/0xe6

  but task is already holding lock:
  (pgdat_init_rwsem){++++.+},
    at: [<ffffffff8424c772>] page_alloc_init_late+0x3e/0xe6

Replace the rwsem by a completion together with an atomic
"outstanding work counter".

[peterz@infradead.org: Barrier removal on the grounds of being pointless]
[mgorman@suse.de: Applied review feedback]
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Alex Ng <alexng@microsoft.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-07 04:39:40 +03:00
Mel Gorman
7ace991707 mm, meminit: allow early_pfn_to_nid to be used during runtime 
early_pfn_to_nid() historically was inherently not SMP safe but only
used during boot which is inherently single threaded or during hotplug
which is protected by a giant mutex.

With deferred memory initialisation there was a thread-safe version
introduced and the early_pfn_to_nid would trigger a BUG_ON if used
unsafely.  Memory hotplug hit that check.  This patch makes
early_pfn_to_nid introduces a lock to make it safe to use during
hotplug.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Alex Ng <alexng@microsoft.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-08-07 04:39:40 +03:00
Joonsoo Kim
e2cfc91120 mm/page_owner: set correct gfp_mask on page_owner 
Currently, we set wrong gfp_mask to page_owner info in case of isolated
freepage by compaction and split page.  It causes incorrect mixed
pageblock report that we can get from '/proc/pagetypeinfo'.  This metric
is really useful to measure fragmentation effect so should be accurate.
This patch fixes it by setting correct information.

Without this patch, after kernel build workload is finished, number of
mixed pageblock is 112 among roughly 210 movable pageblocks.

But, with this fix, output shows that mixed pageblock is just 57.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-07-17 16:39:54 -07:00
Joonsoo Kim
f3a14ced32 mm/page_owner: fix possible access violation 
When I tested my new patches, I found that page pointer which is used
for setting page_owner information is changed.  This is because page
pointer is used to set new migratetype in loop.  After this work, page
pointer could be out of bound.  If this wrong pointer is used for
page_owner, access violation happens.  Below is error message that I
got.

  BUG: unable to handle kernel paging request at 0000000000b00018
  IP: [<ffffffff81025f30>] save_stack_address+0x30/0x40
  PGD 1af2d067 PUD 166e0067 PMD 0
  Oops: 0002 [#1] SMP
  ...snip...
  Call Trace:
    print_context_stack+0xcf/0x100
    dump_trace+0x15f/0x320
    save_stack_trace+0x2f/0x50
    __set_page_owner+0x46/0x70
    __isolate_free_page+0x1f7/0x210
    split_free_page+0x21/0xb0
    isolate_freepages_block+0x1e2/0x410
    compaction_alloc+0x22d/0x2d0
    migrate_pages+0x289/0x8b0
    compact_zone+0x409/0x880
    compact_zone_order+0x6d/0x90
    try_to_compact_pages+0x110/0x210
    __alloc_pages_direct_compact+0x3d/0xe6
    __alloc_pages_nodemask+0x6cd/0x9a0
    alloc_pages_current+0x91/0x100
    runtest_store+0x296/0xa50
    simple_attr_write+0xbd/0xe0
    __vfs_write+0x28/0xf0
    vfs_write+0xa9/0x1b0
    SyS_write+0x46/0xb0
    system_call_fastpath+0x16/0x75

This patch fixes this error by moving up set_page_owner().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-07-17 16:39:54 -07:00
Mel Gorman
ae026b2aa1 mm, meminit: suppress unused memory variable warning 
The kbuild test robot reported the following

  tree:   git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
  head:   14a6f1989d
  commit: 3b242c66cc x86: mm: enable deferred struct page initialisation on x86-64
  date:   3 days ago
  config: x86_64-randconfig-x006-201527 (attached as .config)
  reproduce:
    git checkout 3b242c66cc
    # save the attached .config to linux build tree
    make ARCH=x86_64

  All warnings (new ones prefixed by >>):

     mm/page_alloc.c: In function 'early_page_uninitialised':
  >> mm/page_alloc.c:247:6: warning: unused variable 'nid' [-Wunused-variable]
       int nid = early_pfn_to_nid(pfn);

It's due to the NODE_DATA macro ignoring the nid parameter on !NUMA
configurations.  This patch avoids the warning by not declaring nid.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Wu Fengguang <fengguang.wu@intel.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>
 2015-07-17 16:39:53 -07:00
Mel Gorman
0e1cc95b4c mm: meminit: finish initialisation of struct pages before basic setup 
Waiman Long reported that 24TB machines hit OOM during basic setup when
struct page initialisation was deferred.  One approach is to initialise
memory on demand but it interferes with page allocator paths.  This patch
creates dedicated threads to initialise memory before basic setup.  It
then blocks on a rw_semaphore until completion as a wait_queue and counter
is overkill.  This may be slower to boot but it's simplier overall and
also gets rid of a section mangling which existed so kswapd could do the
initialisation.

[akpm@linux-foundation.org: include rwsem.h, use DECLARE_RWSEM, fix comment, remove unneeded cast]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Waiman Long <waiman.long@hp.com
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Scott Norton <scott.norton@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-30 19:44:56 -07:00
Mel Gorman
74033a798f mm: meminit: remove mminit_verify_page_links 
mminit_verify_page_links() is an extremely paranoid check that was
introduced when memory initialisation was being heavily reworked.
Profiles indicated that up to 10% of parallel memory initialisation was
spent on checking this for every page.  The cost could be reduced but in
practice this check only found problems very early during the
initialisation rewrite and has found nothing since.  This patch removes an
expensive unnecessary check.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
ac5d2539b2 mm: meminit: reduce number of times pageblocks are set during struct page init 
During parallel sturct page initialisation, ranges are checked for every
PFN unnecessarily which increases boot times.  This patch alters when the
ranges are checked.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
a4de83dd33 mm: meminit: free pages in large chunks where possible 
Parallel struct page frees pages one at a time. Try free pages as single
large pages where possible.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
54608c3f3a mm: meminit: minimise number of pfn->page lookups during initialisation 
Deferred struct page initialisation is using pfn_to_page() on every PFN
unnecessarily.  This patch minimises the number of lookups and scheduler
checks.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
7e18adb4f8 mm: meminit: initialise remaining struct pages in parallel with kswapd 
Only a subset of struct pages are initialised at the moment.  When this
patch is applied kswapd initialise the remaining struct pages in parallel.

This should boot faster by spreading the work to multiple CPUs and
initialising data that is local to the CPU.  The user-visible effect on
large machines is that free memory will appear to rapidly increase early
in the lifetime of the system until kswapd reports that all memory is
initialised in the kernel log.  Once initialised there should be no other
user-visibile effects.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
3a80a7fa79 mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set 
This patch initalises all low memory struct pages and 2G of the highest
zone on each node during memory initialisation if
CONFIG_DEFERRED_STRUCT_PAGE_INIT is set.  That config option cannot be set
but will be available in a later patch.  Parallel initialisation of struct
page depends on some features from memory hotplug and it is necessary to
alter alter section annotations.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
75a592a471 mm: meminit: inline some helper functions 
early_pfn_in_nid() and meminit_pfn_in_nid() are small functions that are
unnecessarily visible outside memory initialisation.  As well as
unnecessary visibility, it's unnecessary function call overhead when
initialising pages.  This patch moves the helpers inline.

[akpm@linux-foundation.org: fix build]
[mhocko@suse.cz: fix build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-30 19:44:56 -07:00
Mel Gorman
8a942fdea5 mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid 
__early_pfn_to_nid() use static variables to cache recent lookups as
memblock lookups are very expensive but it assumes that memory
initialisation is single-threaded.  Parallel initialisation of struct
pages will break that assumption so this patch makes __early_pfn_to_nid()
SMP-safe by requiring the caller to cache recent search information.
early_pfn_to_nid() keeps the same interface but is only safe to use early
in boot due to the use of a global static variable.  meminit_pfn_in_nid()
is an SMP-safe version that callers must maintain their own state for.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:56 -07:00
Mel Gorman
d70ddd7a5d mm: page_alloc: pass PFN to __free_pages_bootmem 
__free_pages_bootmem prepares a page for release to the buddy allocator
and assumes that the struct page is initialised.  Parallel initialisation
of struct pages defers initialisation and __free_pages_bootmem can be
called for struct pages that cannot yet map struct page to PFN.  This
patch passes PFN to __free_pages_bootmem with no other functional change.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:55 -07:00
Nathan Zimmer
92923ca3aa mm: meminit: only set page reserved in the memblock region 
Currently each page struct is set as reserved upon initialization.  This
patch leaves the reserved bit clear and only sets the reserved bit when it
is known the memory was allocated by the bootmem allocator.  This makes it
easier to distinguish between uninitialised struct pages and reserved
struct pages in later patches.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:55 -07:00
Robin Holt
1e8ce83cd1 mm: meminit: move page initialization into a separate function 
Currently, memmap_init_zone() has all the smarts for initializing a single
page.  A subset of this is required for parallel page initialisation and
so this patch breaks up the monolithic function in preparation.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
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>
 2015-06-30 19:44:55 -07:00
Linus Torvalds
aefbef10e3 Merge branch 'akpm' (patches from Andrew) 
Merge first patchbomb from Andrew Morton:

 - a few misc things

 - ocfs2 udpates

 - kernel/watchdog.c feature work (took ages to get right)

 - most of MM.  A few tricky bits are held up and probably won't make 4.2.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
  mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
  mm, thp: respect MPOL_PREFERRED policy with non-local node
  tmpfs: truncate prealloc blocks past i_size
  mm/memory hotplug: print the last vmemmap region at the end of hot add memory
  mm/mmap.c: optimization of do_mmap_pgoff function
  mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
  mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
  mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
  mm: kmemleak: fix delete_object_*() race when called on the same memory block
  mm: kmemleak: allow safe memory scanning during kmemleak disabling
  memcg: convert mem_cgroup->under_oom from atomic_t to int
  memcg: remove unused mem_cgroup->oom_wakeups
  frontswap: allow multiple backends
  x86, mirror: x86 enabling - find mirrored memory ranges
  mm/memblock: allocate boot time data structures from mirrored memory
  mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
  mm: do not ignore mapping_gfp_mask in page cache allocation paths
  mm/cma.c: fix typos in comments
  mm/oom_kill.c: print points as unsigned int
  mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
  ...
 2015-06-24 20:47:21 -07:00
Johannes Weiner
9083905a2a mm: page_alloc: inline should_alloc_retry() 
The should_alloc_retry() function was meant to encapsulate retry
conditions of the allocator slowpath, but there are still checks
remaining in the main function, and much of how the retrying is
performed also depends on the OOM killer progress.  The physical
separation of those conditions make the code hard to follow.

Inline the should_alloc_retry() checks.  Notes:

- The __GFP_NOFAIL check is already done in __alloc_pages_may_oom(),
  replace it with looping on OOM killer progress

- The pm_suspended_storage() check is meant to skip the OOM killer
  when reclaim has no IO available, move to __alloc_pages_may_oom()

- The order <= PAGE_ALLOC_COSTLY order is re-united with its original
  counterpart of checking whether reclaim actually made any progress

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-24 17:49:43 -07:00
Johannes Weiner
dc56401fc9 mm: oom_kill: simplify OOM killer locking 
The zonelist locking and the oom_sem are two overlapping locks that are
used to serialize global OOM killing against different things.

The historical zonelist locking serializes OOM kills from allocations with
overlapping zonelists against each other to prevent killing more tasks
than necessary in the same memory domain.  Only when neither tasklists nor
zonelists from two concurrent OOM kills overlap (tasks in separate memcgs
bound to separate nodes) are OOM kills allowed to execute in parallel.

The younger oom_sem is a read-write lock to serialize OOM killing against
the PM code trying to disable the OOM killer altogether.

However, the OOM killer is a fairly cold error path, there is really no
reason to optimize for highly performant and concurrent OOM kills.  And
the oom_sem is just flat-out redundant.

Replace both locking schemes with a single global mutex serializing OOM
kills regardless of context.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-24 17:49:43 -07:00
Gu Zheng
febd5949e1 mm/memory hotplug: init the zone's size when calculating node totalpages 
Init the zone's size when calculating node totalpages to avoid duplicated
operations in free_area_init_core().

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-24 17:49:42 -07:00
Anisse Astier
f4d2897b93 mm/page_alloc.c: cleanup obsolete KM_USER* 
It's been five years now that KM_* kmap flags have been removed and that
we can call clear_highpage from any context.  So we remove prep_zero_pages
accordingly.

Signed-off-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-24 17:49:42 -07:00
Rasmus Villemoes
a9919c7935 mm: only define hashdist variable when needed 
For !CONFIG_NUMA, hashdist will always be 0, since it's setter is
otherwise compiled out.  So we can save 4 bytes of data and some .text
(although mostly in __init functions) by only defining it for
CONFIG_NUMA.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-06-24 17:49:41 -07:00
Alexander Duyck
b63ae8ca09 mm/net: Rename and move page fragment handling from net/ to mm/ 
This change moves the __alloc_page_frag functionality out of the networking
stack and into the page allocation portion of mm.  The idea it so help make
this maintainable by placing it with other page allocation functions.

Since we are moving it from skbuff.c to page_alloc.c I have also renamed
the basic defines and structure from netdev_alloc_cache to page_frag_cache
to reflect that this is now part of a different kernel subsystem.

I have also added a simple __free_page_frag function which can handle
freeing the frags based on the skb->head pointer.  The model for this is
based off of __free_pages since we don't actually need to deal with all of
the cases that put_page handles.  I incorporated the virt_to_head_page call
and compound_order into the function as it actually allows for a signficant
size reduction by reducing code duplication.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 2015-05-12 10:39:26 -04:00
Jason Low
4db0c3c298 mm: remove rest of ACCESS_ONCE() usages 
We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/
tree since it doesn't work reliably on non-scalar types.

This patch removes the rest of the usages of ACCESS_ONCE, and use the new
READ_ONCE API for the read accesses.  This makes things cleaner, instead
of using separate/multiple sets of APIs.

Signed-off-by: Jason Low <jason.low2@hp.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-15 16:35:18 -07:00
Yaowei Bai
42ff27035c mm/page_alloc.c: clean up comment 
Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:04 -07:00
David Rientjes
4167e9b2cf mm: remove GFP_THISNODE 
NOTE: this is not about __GFP_THISNODE, this is only about GFP_THISNODE.

GFP_THISNODE is a secret combination of gfp bits that have different
behavior than expected.  It is a combination of __GFP_THISNODE,
__GFP_NORETRY, and __GFP_NOWARN and is special-cased in the page
allocator slowpath to fail without trying reclaim even though it may be
used in combination with __GFP_WAIT.

An example of the problem this creates: commit e97ca8e5b8 ("mm: fix
GFP_THISNODE callers and clarify") fixed up many users of GFP_THISNODE
that really just wanted __GFP_THISNODE.  The problem doesn't end there,
however, because even it was a no-op for alloc_misplaced_dst_page(),
which also sets __GFP_NORETRY and __GFP_NOWARN, and
migrate_misplaced_transhuge_page(), where __GFP_NORETRY and __GFP_NOWAIT
is set in GFP_TRANSHUGE.  Converting GFP_THISNODE to __GFP_THISNODE is a
no-op in these cases since the page allocator special-cases
__GFP_THISNODE && __GFP_NORETRY && __GFP_NOWARN.

It's time to just remove GFP_THISNODE entirely.  We leave __GFP_THISNODE
to restrict an allocation to a local node, but remove GFP_THISNODE and
its obscurity.  Instead, we require that a caller clear __GFP_WAIT if it
wants to avoid reclaim.

This allows the aforementioned functions to actually reclaim as they
should.  It also enables any future callers that want to do
__GFP_THISNODE but also __GFP_NORETRY && __GFP_NOWARN to reclaim.  The
rule is simple: if you don't want to reclaim, then don't set __GFP_WAIT.

Aside: ovs_flow_stats_update() really wants to avoid reclaim as well, so
it is unchanged.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:03 -07:00
Konstantin Khlebnikov
761b06771a mm: completely remove dumping per-cpu lists from show_mem() 
It seems nobody needs this.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:01 -07:00
Konstantin Khlebnikov
d1bfcdb8ce mm: hide per-cpu lists in output of show_mem() 
This makes show_mem() much less verbose on huge machines.  Instead of huge
and almost useless dump of counters for each per-zone per-cpu lists this
patch prints the sum of these counters for each zone (free_pcp) and size
of per-cpu list for current cpu (local_pcp).

The filter flag SHOW_MEM_PERCPU_LISTS reverts to the old verbose mode.

[akpm@linux-foundation.org: update show_free_areas comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:01 -07:00
Joonsoo Kim
2149cdaef6 mm/compaction: enhance compaction finish condition 
Compaction has anti fragmentation algorithm.  It is that freepage should
be more than pageblock order to finish the compaction if we don't find any
freepage in requested migratetype buddy list.  This is for mitigating
fragmentation, but, there is a lack of migratetype consideration and it is
too excessive compared to page allocator's anti fragmentation algorithm.

Not considering migratetype would cause premature finish of compaction.
For example, if allocation request is for unmovable migratetype, freepage
with CMA migratetype doesn't help that allocation and compaction should
not be stopped.  But, current logic regards this situation as compaction
is no longer needed, so finish the compaction.

Secondly, condition is too excessive compared to page allocator's logic.
We can steal freepage from other migratetype and change pageblock
migratetype on more relaxed conditions in page allocator.  This is
designed to prevent fragmentation and we can use it here.  Imposing hard
constraint only to the compaction doesn't help much in this case since
page allocator would cause fragmentation again.

To solve these problems, this patch borrows anti fragmentation logic from
page allocator.  It will reduce premature compaction finish in some cases
and reduce excessive compaction work.

stress-highalloc test in mmtests with non movable order 7 allocation shows
considerable increase of compaction success rate.

Compaction success rate (Compaction success * 100 / Compaction stalls, %)
31.82 : 42.20

I tested it on non-reboot 5 runs stress-highalloc benchmark and found that
there is no more degradation on allocation success rate than before.  That
roughly means that this patch doesn't result in more fragmentations.

Vlastimil suggests additional idea that we only test for fallbacks when
migration scanner has scanned a whole pageblock.  It looked good for
fragmentation because chance of stealing increase due to making more free
pages in certain pageblock.  So, I tested it, but, it results in decreased
compaction success rate, roughly 38.00.  I guess the reason that if system
is low memory condition, watermark check could be failed due to not enough
order 0 free page and so, sometimes, we can't reach a fallback check
although migrate_pfn is aligned to pageblock_nr_pages.  I can insert code
to cope with this situation but it makes code more complicated so I don't
include his idea at this patch.

[akpm@linux-foundation.org: fix CONFIG_CMA=n build]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:01 -07:00
Joonsoo Kim
4eb7dce620 mm/page_alloc: factor out fallback freepage checking 
This is preparation step to use page allocator's anti fragmentation logic
in compaction.  This patch just separates fallback freepage checking part
from fallback freepage management part.  Therefore, there is no functional
change.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:01 -07:00
Joonsoo Kim
dc67647b78 mm/cma: change fallback behaviour for CMA freepage 
Freepage with MIGRATE_CMA can be used only for MIGRATE_MOVABLE and they
should not be expanded to other migratetype buddy list to protect them
from unmovable/reclaimable allocation.  Implementing these requirements in
__rmqueue_fallback(), that is, finding largest possible block of freepage
has bad effect that high order freepage with MIGRATE_CMA are broken
continually although there are suitable order CMA freepage.  Reason is
that they are not be expanded to other migratetype buddy list and next
__rmqueue_fallback() invocation try to finds another largest block of
freepage and break it again.  So, MIGRATE_CMA fallback should be handled
separately.  This patch introduces __rmqueue_cma_fallback(), that just
wrapper of __rmqueue_smallest() and call it before __rmqueue_fallback() if
migratetype == MIGRATE_MOVABLE.

This results in unintended behaviour change that MIGRATE_CMA freepage is
always used first rather than other migratetype as movable allocation's
fallback.  But, as already mentioned above, MIGRATE_CMA can be used only
for MIGRATE_MOVABLE, so it is better to use MIGRATE_CMA freepage first as
much as possible.  Otherwise, we needlessly take up precious freepages
with other migratetype and increase chance of fragmentation.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-04-14 16:49:01 -07:00
Michal Hocko
e009d5dc0a mm, oom: do not fail __GFP_NOFAIL allocation if oom killer is disabled 
Tetsuo Handa has pointed out that __GFP_NOFAIL allocations might fail
after OOM killer is disabled if the allocation is performed by a kernel
thread.  This behavior was introduced from the very beginning by
7f33d49a2e ("mm, PM/Freezer: Disable OOM killer when tasks are frozen").
 This means that the basic contract for the allocation request is broken
and the context requesting such an allocation might blow up unexpectedly.

There are basically two ways forward.

1) move oom_killer_disable after kernel threads are frozen.  This has a
   risk that the OOM victim wouldn't be able to finish because it would
   depend on an already frozen kernel thread.  This would be really tricky
   to debug.

2) do not fail GFP_NOFAIL allocation no matter what and risk a
   potential Freezable kernel threads will loop and fail the suspend.
   Incidental allocations after kernel threads are frozen will at least
   dump a warning - if we are lucky and the serial console is still active
   of course...

This patch implements the later option because it is safer.  We would see
warning rather than allocation failures for the kernel threads which would
blow up otherwise and have a higher chances to identify __GFP_NOFAIL users
from deeper pm code.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@gooogle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-03-12 18:46:07 -07:00
Johannes Weiner
cc87317726 mm: page_alloc: revert inadvertent !__GFP_FS retry behavior change 
Historically, !__GFP_FS allocations were not allowed to invoke the OOM
killer once reclaim had failed, but nevertheless kept looping in the
allocator.

Commit 9879de7373 ("mm: page_alloc: embed OOM killing naturally into
allocation slowpath"), which should have been a simple cleanup patch,
accidentally changed the behavior to aborting the allocation at that
point.  This creates problems with filesystem callers (?) that currently
rely on the allocator waiting for other tasks to intervene.

Revert the behavior as it shouldn't have been changed as part of a
cleanup patch.

Fixes: 9879de7373 ("mm: page_alloc: embed OOM killing naturally into allocation slowpath")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dave Chinner <david@fromorbit.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>	[3.19.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-28 09:57:51 -08:00
Andrey Ryabinin
b8c73fc249 mm: page_alloc: add kasan hooks on alloc and free paths 
Add kernel address sanitizer hooks to mark allocated page's addresses as
accessible in corresponding shadow region.  Mark freed pages as
inaccessible.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-13 21:21:41 -08:00
Yaowei Bai
84109e15dd mm/page_alloc: fix comment 
Add a necessary 'leave'.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-12 18:54:11 -08:00
Rasmus Villemoes
061f67bc4d mm/page_alloc.c: pull out init code from build_all_zonelists 
Pulling the code protected by if (system_state == SYSTEM_BOOTING) into
its own helper allows us to shrink .text a little. This relies on
build_all_zonelists already having a __ref annotation. Add a comment
explaining why so one doesn't have to track it down through git log.

The real saving comes in 3/5, ("mm/mm_init.c: Mark mminit_verify_zonelist
as __init"), where we save about 400 bytes

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-12 18:54:11 -08:00
Vlastimil Babka
9c0415eb8c mm: more aggressive page stealing for UNMOVABLE allocations 
When allocation falls back to stealing free pages of another migratetype,
it can decide to steal extra pages, or even the whole pageblock in order
to reduce fragmentation, which could happen if further allocation
fallbacks pick a different pageblock.  In try_to_steal_freepages(), one of
the situations where extra pages are stolen happens when we are trying to
allocate a MIGRATE_RECLAIMABLE page.

However, MIGRATE_UNMOVABLE allocations are not treated the same way,
although spreading such allocation over multiple fallback pageblocks is
arguably even worse than it is for RECLAIMABLE allocations.  To minimize
fragmentation, we should minimize the number of such fallbacks, and thus
steal as much as is possible from each fallback pageblock.

Note that in theory this might put more pressure on movable pageblocks and
cause movable allocations to steal back from unmovable pageblocks.
However, movable allocations are not as aggressive with stealing, and do
not cause permanent fragmentation, so the tradeoff is reasonable, and
evaluation seems to support the change.

This patch thus adds a check for MIGRATE_UNMOVABLE to the decision to
steal extra free pages.  When evaluating with stress-highalloc from
mmtests, this has reduced the number of MIGRATE_UNMOVABLE fallbacks to
roughly 1/6.  The number of these fallbacks stealing from MIGRATE_MOVABLE
block is reduced to 1/3.  There was no observation of growing number of
unmovable pageblocks over time, and also not of increased movable
allocation fallbacks.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:06 -08:00
Vlastimil Babka
3a1086fba9 mm: always steal split buddies in fallback allocations 
When allocation falls back to another migratetype, it will steal a page
with highest available order, and (depending on this order and desired
migratetype), it might also steal the rest of free pages from the same
pageblock.

Given the preference of highest available order, it is likely that it will
be higher than the desired order, and result in the stolen buddy page
being split.  The remaining pages after split are currently stolen only
when the rest of the free pages are stolen.  This can however lead to
situations where for MOVABLE allocations we split e.g.  order-4 fallback
UNMOVABLE page, but steal only order-0 page.  Then on the next MOVABLE
allocation (which may be batched to fill the pcplists) we split another
order-3 or higher page, etc.  By stealing all pages that we have split, we
can avoid further stealing.

This patch therefore adjusts the page stealing so that buddy pages created
by split are always stolen.  This has effect only on MOVABLE allocations,
as RECLAIMABLE and UNMOVABLE allocations already always do that in
addition to stealing the rest of free pages from the pageblock.  The
change also allows to simplify try_to_steal_freepages() and factor out CMA
handling.

According to Mel, it has been intended since the beginning that buddy
pages after split would be stolen always, but it doesn't seem like it was
ever the case until commit 47118af076 ("mm: mmzone: MIGRATE_CMA
migration type added").  The commit has unintentionally introduced this
behavior, but was reverted by commit 0cbef29a78 ("mm:
__rmqueue_fallback() should respect pageblock type").  Neither included
evaluation.

My evaluation with stress-highalloc from mmtests shows about 2.5x
reduction of page stealing events for MOVABLE allocations, without
affecting the page stealing events for other allocation migratetypes.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:06 -08:00
Vlastimil Babka
99592d598e mm: when stealing freepages, also take pages created by splitting buddy page 
When studying page stealing, I noticed some weird looking decisions in
try_to_steal_freepages().  The first I assume is a bug (Patch 1), the
following two patches were driven by evaluation.

Testing was done with stress-highalloc of mmtests, using the
mm_page_alloc_extfrag tracepoint and postprocessing to get counts of how
often page stealing occurs for individual migratetypes, and what
migratetypes are used for fallbacks.  Arguably, the worst case of page
stealing is when UNMOVABLE allocation steals from MOVABLE pageblock.
RECLAIMABLE allocation stealing from MOVABLE allocation is also not ideal,
so the goal is to minimize these two cases.

The evaluation of v2 wasn't always clear win and Joonsoo questioned the
results.  Here I used different baseline which includes RFC compaction
improvements from [1].  I found that the compaction improvements reduce
variability of stress-highalloc, so there's less noise in the data.

First, let's look at stress-highalloc configured to do sync compaction,
and how these patches reduce page stealing events during the test.  First
column is after fresh reboot, other two are reiterations of test without
reboot.  That was all accumulater over 5 re-iterations (so the benchmark
was run 5x3 times with 5 fresh restarts).

Baseline:

                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                  5-nothp-1       5-nothp-2       5-nothp-3
Page alloc extfrag event                               10264225     8702233    10244125
Extfrag fragmenting                                    10263271     8701552    10243473
Extfrag fragmenting for unmovable                         13595       17616       15960
Extfrag fragmenting unmovable placed with movable          7989       12193        8447
Extfrag fragmenting for reclaimable                         658        1840        1817
Extfrag fragmenting reclaimable placed with movable         558        1677        1679
Extfrag fragmenting for movable                        10249018     8682096    10225696

With Patch 1:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                  6-nothp-1       6-nothp-2       6-nothp-3
Page alloc extfrag event                               11834954     9877523     9774860
Extfrag fragmenting                                    11833993     9876880     9774245
Extfrag fragmenting for unmovable                          7342       16129       11712
Extfrag fragmenting unmovable placed with movable          4191       10547        6270
Extfrag fragmenting for reclaimable                         373        1130         923
Extfrag fragmenting reclaimable placed with movable         302         906         738
Extfrag fragmenting for movable                        11826278     9859621     9761610

With Patch 2:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                  7-nothp-1       7-nothp-2       7-nothp-3
Page alloc extfrag event                                4725990     3668793     3807436
Extfrag fragmenting                                     4725104     3668252     3806898
Extfrag fragmenting for unmovable                          6678        7974        7281
Extfrag fragmenting unmovable placed with movable          2051        3829        4017
Extfrag fragmenting for reclaimable                         429        1208        1278
Extfrag fragmenting reclaimable placed with movable         369         976        1034
Extfrag fragmenting for movable                         4717997     3659070     3798339

With Patch 3:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                  8-nothp-1       8-nothp-2       8-nothp-3
Page alloc extfrag event                                5016183     4700142     3850633
Extfrag fragmenting                                     5015325     4699613     3850072
Extfrag fragmenting for unmovable                          1312        3154        3088
Extfrag fragmenting unmovable placed with movable          1115        2777        2714
Extfrag fragmenting for reclaimable                         437        1193        1097
Extfrag fragmenting reclaimable placed with movable         330         969         879
Extfrag fragmenting for movable                         5013576     4695266     3845887

In v2 we've seen apparent regression with Patch 1 for unmovable events,
this is now gone, suggesting it was indeed noise.  Here, each patch
improves the situation for unmovable events.  Reclaimable is improved by
patch 1 and then either the same modulo noise, or perhaps sligtly worse -
a small price for unmovable improvements, IMHO.  The number of movable
allocations falling back to other migratetypes is most noisy, but it's
reduced to half at Patch 2 nevertheless.  These are least critical as
compaction can move them around.

If we look at success rates, the patches don't affect them, that didn't change.

Baseline:
                             3.19-rc4              3.19-rc4              3.19-rc4
                            5-nothp-1             5-nothp-2             5-nothp-3
Success 1 Min         49.00 (  0.00%)       42.00 ( 14.29%)       41.00 ( 16.33%)
Success 1 Mean        51.00 (  0.00%)       45.00 ( 11.76%)       42.60 ( 16.47%)
Success 1 Max         55.00 (  0.00%)       51.00 (  7.27%)       46.00 ( 16.36%)
Success 2 Min         53.00 (  0.00%)       47.00 ( 11.32%)       44.00 ( 16.98%)
Success 2 Mean        59.60 (  0.00%)       50.80 ( 14.77%)       48.20 ( 19.13%)
Success 2 Max         64.00 (  0.00%)       56.00 ( 12.50%)       52.00 ( 18.75%)
Success 3 Min         84.00 (  0.00%)       82.00 (  2.38%)       78.00 (  7.14%)
Success 3 Mean        85.60 (  0.00%)       82.80 (  3.27%)       79.40 (  7.24%)
Success 3 Max         86.00 (  0.00%)       83.00 (  3.49%)       80.00 (  6.98%)

Patch 1:
                             3.19-rc4              3.19-rc4              3.19-rc4
                            6-nothp-1             6-nothp-2             6-nothp-3
Success 1 Min         49.00 (  0.00%)       44.00 ( 10.20%)       44.00 ( 10.20%)
Success 1 Mean        51.80 (  0.00%)       46.00 ( 11.20%)       45.80 ( 11.58%)
Success 1 Max         54.00 (  0.00%)       49.00 (  9.26%)       49.00 (  9.26%)
Success 2 Min         58.00 (  0.00%)       49.00 ( 15.52%)       48.00 ( 17.24%)
Success 2 Mean        60.40 (  0.00%)       51.80 ( 14.24%)       50.80 ( 15.89%)
Success 2 Max         63.00 (  0.00%)       54.00 ( 14.29%)       55.00 ( 12.70%)
Success 3 Min         84.00 (  0.00%)       81.00 (  3.57%)       79.00 (  5.95%)
Success 3 Mean        85.00 (  0.00%)       81.60 (  4.00%)       79.80 (  6.12%)
Success 3 Max         86.00 (  0.00%)       82.00 (  4.65%)       82.00 (  4.65%)

Patch 2:

                             3.19-rc4              3.19-rc4              3.19-rc4
                            7-nothp-1             7-nothp-2             7-nothp-3
Success 1 Min         50.00 (  0.00%)       44.00 ( 12.00%)       39.00 ( 22.00%)
Success 1 Mean        52.80 (  0.00%)       45.60 ( 13.64%)       42.40 ( 19.70%)
Success 1 Max         55.00 (  0.00%)       46.00 ( 16.36%)       47.00 ( 14.55%)
Success 2 Min         52.00 (  0.00%)       48.00 (  7.69%)       45.00 ( 13.46%)
Success 2 Mean        53.40 (  0.00%)       49.80 (  6.74%)       48.80 (  8.61%)
Success 2 Max         57.00 (  0.00%)       52.00 (  8.77%)       52.00 (  8.77%)
Success 3 Min         84.00 (  0.00%)       81.00 (  3.57%)       79.00 (  5.95%)
Success 3 Mean        85.00 (  0.00%)       82.40 (  3.06%)       79.60 (  6.35%)
Success 3 Max         86.00 (  0.00%)       83.00 (  3.49%)       80.00 (  6.98%)

Patch 3:
                             3.19-rc4              3.19-rc4              3.19-rc4
                            8-nothp-1             8-nothp-2             8-nothp-3
Success 1 Min         46.00 (  0.00%)       44.00 (  4.35%)       42.00 (  8.70%)
Success 1 Mean        50.20 (  0.00%)       45.60 (  9.16%)       44.00 ( 12.35%)
Success 1 Max         52.00 (  0.00%)       47.00 (  9.62%)       47.00 (  9.62%)
Success 2 Min         53.00 (  0.00%)       49.00 (  7.55%)       48.00 (  9.43%)
Success 2 Mean        55.80 (  0.00%)       50.60 (  9.32%)       49.00 ( 12.19%)
Success 2 Max         59.00 (  0.00%)       52.00 ( 11.86%)       51.00 ( 13.56%)
Success 3 Min         84.00 (  0.00%)       80.00 (  4.76%)       79.00 (  5.95%)
Success 3 Mean        85.40 (  0.00%)       81.60 (  4.45%)       80.40 (  5.85%)
Success 3 Max         87.00 (  0.00%)       83.00 (  4.60%)       82.00 (  5.75%)

While there's no improvement here, I consider reduced fragmentation events
to be worth on its own.  Patch 2 also seems to reduce scanning for free
pages, and migrations in compaction, suggesting it has somewhat less work
to do:

Patch 1:

Compaction stalls                 4153        3959        3978
Compaction success                1523        1441        1446
Compaction failures               2630        2517        2531
Page migrate success           4600827     4943120     5104348
Page migrate failure             19763       16656       17806
Compaction pages isolated      9597640    10305617    10653541
Compaction migrate scanned    77828948    86533283    87137064
Compaction free scanned      517758295   521312840   521462251
Compaction cost                   5503        5932        6110

Patch 2:

Compaction stalls                 3800        3450        3518
Compaction success                1421        1316        1317
Compaction failures               2379        2134        2201
Page migrate success           4160421     4502708     4752148
Page migrate failure             19705       14340       14911
Compaction pages isolated      8731983     9382374     9910043
Compaction migrate scanned    98362797    96349194    98609686
Compaction free scanned      496512560   469502017   480442545
Compaction cost                   5173        5526        5811

As with v2, /proc/pagetypeinfo appears unaffected with respect to numbers
of unmovable and reclaimable pageblocks.

Configuring the benchmark to allocate like THP page fault (i.e.  no sync
compaction) gives much noisier results for iterations 2 and 3 after
reboot.  This is not so surprising given how [1] offers lower improvements
in this scenario due to less restarts after deferred compaction which
would change compaction pivot.

Baseline:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                    5-thp-1         5-thp-2         5-thp-3
Page alloc extfrag event                                8148965     6227815     6646741
Extfrag fragmenting                                     8147872     6227130     6646117
Extfrag fragmenting for unmovable                         10324       12942       15975
Extfrag fragmenting unmovable placed with movable          5972        8495       10907
Extfrag fragmenting for reclaimable                         601        1707        2210
Extfrag fragmenting reclaimable placed with movable         520        1570        2000
Extfrag fragmenting for movable                         8136947     6212481     6627932

Patch 1:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                    6-thp-1         6-thp-2         6-thp-3
Page alloc extfrag event                                8345457     7574471     7020419
Extfrag fragmenting                                     8343546     7573777     7019718
Extfrag fragmenting for unmovable                         10256       18535       30716
Extfrag fragmenting unmovable placed with movable          6893       11726       22181
Extfrag fragmenting for reclaimable                         465        1208        1023
Extfrag fragmenting reclaimable placed with movable         353         996         843
Extfrag fragmenting for movable                         8332825     7554034     6987979

Patch 2:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                    7-thp-1         7-thp-2         7-thp-3
Page alloc extfrag event                                3512847     3020756     2891625
Extfrag fragmenting                                     3511940     3020185     2891059
Extfrag fragmenting for unmovable                          9017        6892        6191
Extfrag fragmenting unmovable placed with movable          1524        3053        2435
Extfrag fragmenting for reclaimable                         445        1081        1160
Extfrag fragmenting reclaimable placed with movable         375         918         986
Extfrag fragmenting for movable                         3502478     3012212     2883708

Patch 3:
                                                   3.19-rc4        3.19-rc4        3.19-rc4
                                                    8-thp-1         8-thp-2         8-thp-3
Page alloc extfrag event                                3181699     3082881     2674164
Extfrag fragmenting                                     3180812     3082303     2673611
Extfrag fragmenting for unmovable                          1201        4031        4040
Extfrag fragmenting unmovable placed with movable           974        3611        3645
Extfrag fragmenting for reclaimable                         478        1165        1294
Extfrag fragmenting reclaimable placed with movable         387         985        1030
Extfrag fragmenting for movable                         3179133     3077107     2668277

The improvements for first iteration are clear, the rest is much noisier
and can appear like regression for Patch 1.  Anyway, patch 2 rectifies it.

Allocation success rates are again unaffected so there's no point in
making this e-mail any longer.

[1] http://marc.info/?l=linux-mm&m=142166196321125&w=2

This patch (of 3):

When __rmqueue_fallback() is called to allocate a page of order X, it will
find a page of order Y >= X of a fallback migratetype, which is different
from the desired migratetype.  With the help of try_to_steal_freepages(),
it may change the migratetype (to the desired one) also of:

1) all currently free pages in the pageblock containing the fallback page
2) the fallback pageblock itself
3) buddy pages created by splitting the fallback page (when Y > X)

These decisions take the order Y into account, as well as the desired
migratetype, with the goal of preventing multiple fallback allocations
that could e.g.  distribute UNMOVABLE allocations among multiple
pageblocks.

Originally, decision for 1) has implied the decision for 3).  Commit
47118af076 ("mm: mmzone: MIGRATE_CMA migration type added") changed that
(probably unintentionally) so that the buddy pages in case 3) are always
changed to the desired migratetype, except for CMA pageblocks.

Commit fef903efcf ("mm/page_allo.c: restructure free-page stealing code
and fix a bug") did some refactoring and added a comment that the case of
3) is intended.  Commit 0cbef29a78 ("mm: __rmqueue_fallback() should
respect pageblock type") removed the comment and tried to restore the
original behavior where 1) implies 3), but due to the previous
refactoring, the result is instead that only 2) implies 3) - and the
conditions for 2) are less frequently met than conditions for 1).  This
may increase fragmentation in situations where the code decides to steal
all free pages from the pageblock (case 1)), but then gives back the buddy
pages produced by splitting.

This patch restores the original intended logic where 1) implies 3).
During testing with stress-highalloc from mmtests, this has shown to
decrease the number of events where UNMOVABLE and RECLAIMABLE allocations
steal from MOVABLE pageblocks, which can lead to permanent fragmentation.
In some cases it has increased the number of events when MOVABLE
allocations steal from UNMOVABLE or RECLAIMABLE pageblocks, but these are
fixable by sync compaction and thus less harmful.

Note that evaluation has shown that the behavior introduced by
47118af076 for buddy pages in case 3) is actually even better than the
original logic, so the following patch will introduce it properly once
again.  For stable backports of this patch it makes thus sense to only fix
versions containing 0cbef29a78.

[iamjoonsoo.kim@lge.com: tracepoint fix]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>	[3.13+ containing 0cbef29a78]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:06 -08:00
Michal Hocko
c32b3cbe0d oom, PM: make OOM detection in the freezer path raceless 
Commit 5695be142e ("OOM, PM: OOM killed task shouldn't escape PM
suspend") has left a race window when OOM killer manages to
note_oom_kill after freeze_processes checks the counter.  The race
window is quite small and really unlikely and partial solution deemed
sufficient at the time of submission.

Tejun wasn't happy about this partial solution though and insisted on a
full solution.  That requires the full OOM and freezer's task freezing
exclusion, though.  This is done by this patch which introduces oom_sem
RW lock and turns oom_killer_disable() into a full OOM barrier.

oom_killer_disabled check is moved from the allocation path to the OOM
level and we take oom_sem for reading for both the check and the whole
OOM invocation.

oom_killer_disable() takes oom_sem for writing so it waits for all
currently running OOM killer invocations.  Then it disable all the further
OOMs by setting oom_killer_disabled and checks for any oom victims.
Victims are counted via mark_tsk_oom_victim resp.  unmark_oom_victim.  The
last victim wakes up all waiters enqueued by oom_killer_disable().
Therefore this function acts as the full OOM barrier.

The page fault path is covered now as well although it was assumed to be
safe before.  As per Tejun, "We used to have freezing points deep in file
system code which may be reacheable from page fault." so it would be
better and more robust to not rely on freezing points here.  Same applies
to the memcg OOM killer.

out_of_memory tells the caller whether the OOM was allowed to trigger and
the callers are supposed to handle the situation.  The page allocation
path simply fails the allocation same as before.  The page fault path will
retry the fault (more on that later) and Sysrq OOM trigger will simply
complain to the log.

Normally there wouldn't be any unfrozen user tasks after
try_to_freeze_tasks so the function will not block. But if there was an
OOM killer racing with try_to_freeze_tasks and the OOM victim didn't
finish yet then we have to wait for it. This should complete in a finite
time, though, because

	- the victim cannot loop in the page fault handler (it would die
	  on the way out from the exception)
	- it cannot loop in the page allocator because all the further
	  allocation would fail and __GFP_NOFAIL allocations are not
	  acceptable at this stage
	- it shouldn't be blocked on any locks held by frozen tasks
	  (try_to_freeze expects lockless context) and kernel threads and
	  work queues are not frozen yet

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Suggested-by: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:03 -08:00
Juergen Gross
8d29e18a45 mm: use correct format specifiers when printing address ranges 
Especially on 32 bit kernels memory node ranges are printed with 32 bit
wide addresses only.  Use u64 types and %llx specifiers to print full
width of addresses.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Kirill A. Shutemov
81422f29c5 mm: more checks on free_pages_prepare() for tail pages 
Although it was not called, destroy_compound_page() did some potentially
useful checks.  Let's re-introduce them in free_pages_prepare(), where
they can be actually triggered when CONFIG_DEBUG_VM=y.

compound_order() assert is already in free_pages_prepare().  We have few
checks for tail pages left.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Kirill A. Shutemov
6e9f0d582d mm/page_alloc.c: drop dead destroy_compound_page() 
The only caller is __free_one_page(). By the time we should have
page->flags to be cleared already:

 - for 0-order pages though PCP list:
	free_hot_cold_page()
		free_pages_prepare()
			free_pages_check()
				page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
		<put the page to PCP list>

	free_pcppages_bulk()
		page = <withdraw pages from PCP list>
		__free_one_page(page)

 - for non-0-order pages:
	__free_pages_ok()
		free_pages_prepare()
			free_pages_check()
				page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
		free_one_page()
			__free_one_page()

So there's no way PageCompound() will return true in __free_one_page().
Let's remove dead destroy_compound_page() and put assert for page->flags
there instead.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Vlastimil Babka
1a6d53a105 mm: reduce try_to_compact_pages parameters 
Expand the usage of the struct alloc_context introduced in the previous
patch also for calling try_to_compact_pages(), to reduce the number of its
parameters.  Since the function is in different compilation unit, we need
to move alloc_context definition in the shared mm/internal.h header.

With this change we get simpler code and small savings of code size and stack
usage:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27)
function                                     old     new   delta
__alloc_pages_direct_compact                 283     256     -27
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-13 (-13)
function                                     old     new   delta
try_to_compact_pages                         582     569     -13

Stack usage of __alloc_pages_direct_compact goes from 24 to none (per
scripts/checkstack.pl).

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Vlastimil Babka
a9263751e1 mm, page_alloc: reduce number of alloc_pages* functions' parameters 
Introduce struct alloc_context to accumulate the numerous parameters
passed between the alloc_pages* family of functions and
get_page_from_freelist().  This excludes gfp_flags and alloc_info, which
mutate too much along the way, and allocation order, which is conceptually
different.

The result is shorter function signatures, as well as overal code size and
stack usage reductions.

bloat-o-meter:

add/remove: 0/0 grow/shrink: 1/2 up/down: 127/-310 (-183)
function                                     old     new   delta
get_page_from_freelist                      2525    2652    +127
__alloc_pages_direct_compact                 329     283     -46
__alloc_pages_nodemask                      2564    2300    -264

checkstack.pl:

function                            old    new
__alloc_pages_nodemask              248    200
get_page_from_freelist              168    184
__alloc_pages_direct_compact         40     24

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Vlastimil Babka
753791910e mm: set page->pfmemalloc in prep_new_page() 
The possibility of replacing the numerous parameters of alloc_pages*
functions with a single structure has been discussed when Minchan proposed
to expand the x86 kernel stack [1].  This series implements the change,
along with few more cleanups/microoptimizations.

The series is based on next-20150108 and I used gcc 4.8.3 20140627 on
openSUSE 13.2 for compiling.  Config includess NUMA and COMPACTION.

The core change is the introduction of a new struct alloc_context, which looks
like this:

struct alloc_context {
        struct zonelist *zonelist;
        nodemask_t *nodemask;
        struct zone *preferred_zone;
        int classzone_idx;
        int migratetype;
        enum zone_type high_zoneidx;
};

All the contents is mostly constant, except that __alloc_pages_slowpath()
changes preferred_zone, classzone_idx and potentially zonelist.  But
that's not a problem in case control returns to retry_cpuset: in
__alloc_pages_nodemask(), those will be reset to initial values again
(although it's a bit subtle).  On the other hand, gfp_flags and alloc_info
mutate so much that it doesn't make sense to put them into alloc_context.
Still, the result is one parameter instead of up to 7.  This is all in
Patch 2.

Patch 3 is a step to expand alloc_context usage out of page_alloc.c
itself.  The function try_to_compact_pages() can also much benefit from
the parameter reduction, but it means the struct definition has to be
moved to a shared header.

Patch 1 should IMHO be included even if the rest is deemed not useful
enough.  It improves maintainability and also has some code/stack
reduction.  Patch 4 is OTOH a tiny optimization.

Overall bloat-o-meter results:

add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-460 (-460)
function                                     old     new   delta
nr_free_zone_pages                           129     115     -14
__alloc_pages_direct_compact                 329     256     -73
get_page_from_freelist                      2670    2576     -94
__alloc_pages_nodemask                      2564    2285    -279
try_to_compact_pages                         582     579      -3

Overall stack sizes per ./scripts/checkstack.pl:

                          old   new delta
get_page_from_freelist:   184   184     0
__alloc_pages_nodemask    248   200   -48
__alloc_pages_direct_c     40     -   -40
try_to_compact_pages       72    72     0
                                      -88

[1] http://marc.info/?l=linux-mm&m=140142462528257&w=2

This patch (of 4):

prep_new_page() sets almost everything in the struct page of the page
being allocated, except page->pfmemalloc.  This is not obvious and has at
least once led to a bug where page->pfmemalloc was forgotten to be set
correctly, see commit 8fb74b9fb2 ("mm: compaction: partially revert
capture of suitable high-order page").

This patch moves the pfmemalloc setting to prep_new_page(), which means it
needs to gain alloc_flags parameter.  The call to prep_new_page is moved
from buffered_rmqueue() to get_page_from_freelist(), which also leads to
simpler code.  An obsolete comment for buffered_rmqueue() is replaced.

In addition to better maintainability there is a small reduction of code
and stack usage for get_page_from_freelist(), which inlines the other
functions involved.

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-145 (-145)
function                                     old     new   delta
get_page_from_freelist                      2670    2525    -145

Stack usage is reduced from 184 to 168 bytes.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:02 -08:00
Xishi Qiu
23f086f962 kmemcheck: move hook into __alloc_pages_nodemask() for the page allocator 
Now kmemcheck_pagealloc_alloc() is only called by __alloc_pages_slowpath().
__alloc_pages_nodemask()
	__alloc_pages_slowpath()
		kmemcheck_pagealloc_alloc()

And the page will not be tracked by kmemcheck in the following path.
__alloc_pages_nodemask()
	get_page_from_freelist()

So move kmemcheck_pagealloc_alloc() into __alloc_pages_nodemask(),
like this:
__alloc_pages_nodemask()
	...
	get_page_from_freelist()
	if (!page)
		__alloc_pages_slowpath()
	kmemcheck_pagealloc_alloc()
	...

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:01 -08:00
Andrew Morton
91fbdc0f89 mm/page_alloc.c:__alloc_pages_nodemask(): don't alter arg gfp_mask 
__alloc_pages_nodemask() strips __GFP_IO when retrying the page
allocation.  But it does this by altering the function-wide variable
gfp_mask.  This will cause subsequent allocation attempts to inadvertently
use the modified gfp_mask.

Also, pass the correct mask (the mask we actually used) into
trace_mm_page_alloc().

Cc: Ming Lei <ming.lei@canonical.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-11 17:06:01 -08:00
Weijie Yang
4c5018ce06 mm/page_alloc.c: place zone_id check before VM_BUG_ON_PAGE check 
If the freeing page and its buddy page are not at the same zone, the
current holding zone->lock for the freeing page cann't prevent buddy page
getting allocated, this could trigger VM_BUG_ON_PAGE in page_is_buddy() at
a very tiny chance, such as:

cpu 0:						cpu 1:
hold zone_1 lock
check page and it buddy
PageBuddy(buddy) is true			hold zone_2 lock
page_order(buddy) == order is true		alloc buddy
trigger VM_BUG_ON_PAGE(page_count(buddy) != 0)

zone_1->lock prevents the freeing page getting allocated
zone_2->lock prevents the buddy page getting allocated
they are not the same zone->lock.

If we can't remove the zone_id check statement, it's better handle this
rare race.  This patch fixes this by placing the zone_id check before the
VM_BUG_ON_PAGE check.

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-02-10 14:30:34 -08:00
Johannes Weiner
9879de7373 mm: page_alloc: embed OOM killing naturally into allocation slowpath 
The OOM killing invocation does a lot of duplicative checks against the
task's allocation context.  Rework it to take advantage of the existing
checks in the allocator slowpath.

The OOM killer is invoked when the allocator is unable to reclaim any
pages but the allocation has to keep looping.  Instead of having a check
for __GFP_NORETRY hidden in oom_gfp_allowed(), just move the OOM
invocation to the true branch of should_alloc_retry().  The __GFP_FS
check from oom_gfp_allowed() can then be moved into the OOM avoidance
branch in __alloc_pages_may_oom(), along with the PF_DUMPCORE test.

__alloc_pages_may_oom() can then signal to the caller whether the OOM
killer was invoked, instead of requiring it to duplicate the order and
high_zoneidx checks to guess this when deciding whether to continue.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2015-01-26 13:37:18 -08:00
Pintu Kumar
e48322abb0 mm: cma: split cma-reserved in dmesg log 
When the system boots up, in the dmesg logs we can see the memory
statistics along with total reserved as below.  Memory: 458840k/458840k
available, 65448k reserved, 0K highmem

When CMA is enabled, still the total reserved memory remains the same.
However, the CMA memory is not considered as reserved.  But, when we see
/proc/meminfo, the CMA memory is part of free memory.  This creates
confusion.  This patch corrects the problem by properly subtracting the
CMA reserved memory from the total reserved memory in dmesg logs.

Below is the dmesg snapshot from an arm based device with 512MB RAM and
12MB single CMA region.

Before this change:
  Memory: 458840k/458840k available, 65448k reserved, 0K highmem

After this change:
  Memory: 458840k/458840k available, 53160k reserved, 12288k cma-reserved, 0K highmem

Signed-off-by: Pintu Kumar <pintu.k@samsung.com>
Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-18 19:08:10 -08:00
Zhong Hongbo
ba914f4815 mm: remove the highmem zones' memmap in the highmem zone 
Since 01cefaef40 ("mm: provide more accurate estimation
of pages occupied by memmap") allocate the pages from lowmem for the
highmem zones' memmap. So It is not need to reserver the memmap's for
the highmem.

A 2G DDR3 for the arm platform:
On node 0 totalpages: 524288
free_area_init_node: node 0, pgdat 80ccd380, node_mem_map 80d38000
  DMA zone: 3568 pages used for memmap
  DMA zone: 0 pages reserved
  DMA zone: 456704 pages, LIFO batch:31
  HighMem zone: 528 pages used for memmap
  HighMem zone: 67584 pages, LIFO batch:15

On node 0 totalpages: 524288
free_area_init_node: node 0, pgdat 80cd6f40, node_mem_map 80d42000
  DMA zone: 3568 pages used for memmap
  DMA zone: 0 pages reserved
  DMA zone: 456704 pages, LIFO batch:31
  HighMem zone: 67584 pages, LIFO batch:15

Signed-off-by: Hongbo Zhong <hongbo.zhong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:49 -08:00
Johannes Weiner
6b4f7799c6 mm: vmscan: invoke slab shrinkers from shrink_zone() 
The slab shrinkers are currently invoked from the zonelist walkers in
kswapd, direct reclaim, and zone reclaim, all of which roughly gauge the
eligible LRU pages and assemble a nodemask to pass to NUMA-aware
shrinkers, which then again have to walk over the nodemask.  This is
redundant code, extra runtime work, and fairly inaccurate when it comes to
the estimation of actually scannable LRU pages.  The code duplication will
only get worse when making the shrinkers cgroup-aware and requiring them
to have out-of-band cgroup hierarchy walks as well.

Instead, invoke the shrinkers from shrink_zone(), which is where all
reclaimers end up, to avoid this duplication.

Take the count for eligible LRU pages out of get_scan_count(), which
considers many more factors than just the availability of swap space, like
zone_reclaimable_pages() currently does.  Accumulate the number over all
visited lruvecs to get the per-zone value.

Some nodes have multiple zones due to memory addressing restrictions.  To
avoid putting too much pressure on the shrinkers, only invoke them once
for each such node, using the class zone of the allocation as the pivot
zone.

For now, this integrates the slab shrinking better into the reclaim logic
and gets rid of duplicative invocations from kswapd, direct reclaim, and
zone reclaim.  It also prepares for cgroup-awareness, allowing
memcg-capable shrinkers to be added at the lruvec level without much
duplication of both code and runtime work.

This changes kswapd behavior, which used to invoke the shrinkers for each
zone, but with scan ratios gathered from the entire node, resulting in
meaningless pressure quantities on multi-zone nodes.

Zone reclaim behavior also changes.  It used to shrink slabs until the
same amount of pages were shrunk as were reclaimed from the LRUs.  Now it
merely invokes the shrinkers once with the zone's scan ratio, which makes
the shrinkers go easier on caches that implement aging and would prefer
feeding back pressure from recently used slab objects to unused LRU pages.

[vdavydov@parallels.com: assure class zone is populated]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:48 -08:00
Joonsoo Kim
48c96a3685 mm/page_owner: keep track of page owners 
This is the page owner tracking code which is introduced so far ago.  It
is resident on Andrew's tree, though, nobody tried to upstream so it
remain as is.  Our company uses this feature actively to debug memory leak
or to find a memory hogger so I decide to upstream this feature.

This functionality help us to know who allocates the page.  When
allocating a page, we store some information about allocation in extra
memory.  Later, if we need to know status of all pages, we can get and
analyze it from this stored information.

In previous version of this feature, extra memory is statically defined in
struct page, but, in this version, extra memory is allocated outside of
struct page.  It enables us to turn on/off this feature at boottime
without considerable memory waste.

Although we already have tracepoint for tracing page allocation/free,
using it to analyze page owner is rather complex.  We need to enlarge the
trace buffer for preventing overlapping until userspace program launched.
And, launched program continually dump out the trace buffer for later
analysis and it would change system behaviour with more possibility rather
than just keeping it in memory, so bad for debug.

Moreover, we can use page_owner feature further for various purposes.  For
example, we can use it for fragmentation statistics implemented in this
patch.  And, I also plan to implement some CMA failure debugging feature
using this interface.

I'd like to give the credit for all developers contributed this feature,
but, it's not easy because I don't know exact history.  Sorry about that.
Below is people who has "Signed-off-by" in the patches in Andrew's tree.

Contributor:
Alexander Nyberg <alexn@dsv.su.se>
Mel Gorman <mgorman@suse.de>
Dave Hansen <dave@linux.vnet.ibm.com>
Minchan Kim <minchan@kernel.org>
Michal Nazarewicz <mina86@mina86.com>
Andrew Morton <akpm@linux-foundation.org>
Jungsoo Son <jungsoo.son@lge.com>

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:48 -08:00
Joonsoo Kim
031bc5743f mm/debug-pagealloc: make debug-pagealloc boottime configurable 
Now, we have prepared to avoid using debug-pagealloc in boottime.  So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.

Only non-intuitive part is change of guard page functions.  Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:48 -08:00
Joonsoo Kim
e30825f186 mm/debug-pagealloc: prepare boottime configurable on/off 
Until now, debug-pagealloc needs extra flags in struct page, so we need to
recompile whole source code when we decide to use it.  This is really
painful, because it takes some time to recompile and sometimes rebuild is
not possible due to third party module depending on struct page.  So, we
can't use this good feature in many cases.

Now, we have the page extension feature that allows us to insert extra
flags to outside of struct page.  This gets rid of third party module
issue mentioned above.  And, this allows us to determine if we need extra
memory for this page extension in boottime.  With these property, we can
avoid using debug-pagealloc in boottime with low computational overhead in
the kernel built with CONFIG_DEBUG_PAGEALLOC.  This will help our
development process greatly.

This patch is the preparation step to achive above goal.  debug-pagealloc
originally uses extra field of struct page, but, after this patch, it will
use field of struct page_ext.  Because memory for page_ext is allocated
later than initialization of page allocator in CONFIG_SPARSEMEM, we should
disable debug-pagealloc feature temporarily until initialization of
page_ext.  This patch implements this.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:48 -08:00
Joonsoo Kim
eefa864b70 mm/page_ext: resurrect struct page extending code for debugging 
When we debug something, we'd like to insert some information to every
page.  For this purpose, we sometimes modify struct page itself.  But,
this has drawbacks.  First, it requires re-compile.  This makes us
hesitate to use the powerful debug feature so development process is
slowed down.  And, second, sometimes it is impossible to rebuild the
kernel due to third party module dependency.  At third, system behaviour
would be largely different after re-compile, because it changes size of
struct page greatly and this structure is accessed by every part of
kernel.  Keeping this as it is would be better to reproduce errornous
situation.

This feature is intended to overcome above mentioned problems.  This
feature allocates memory for extended data per page in certain place
rather than the struct page itself.  This memory can be accessed by the
accessor functions provided by this code.  During the boot process, it
checks whether allocation of huge chunk of memory is needed or not.  If
not, it avoids allocating memory at all.  With this advantage, we can
include this feature into the kernel in default and can avoid rebuild and
solve related problems.

Until now, memcg uses this technique.  But, now, memcg decides to embed
their variable to struct page itself and it's code to extend struct page
has been removed.  I'd like to use this code to develop debug feature, so
this patch resurrect it.

To help these things to work well, this patch introduces two callbacks for
clients.  One is the need callback which is mandatory if user wants to
avoid useless memory allocation at boot-time.  The other is optional, init
callback, which is used to do proper initialization after memory is
allocated.  Detailed explanation about purpose of these functions is in
code comment.  Please refer it.

Others are completely same with previous extension code in memcg.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:48 -08:00
Joonsoo Kim
2847cf95c6 mm/debug-pagealloc: cleanup page guard code 
Page guard is used by debug-pagealloc feature.  Currently, it is
open-coded, but, I think that more abstraction of it makes core page
allocator code more readable.

There is no functional difference.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-13 12:42:46 -08:00
Linus Torvalds
2756d373a3 Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 
Pull cgroup update from Tejun Heo:
 "cpuset got simplified a bit.  cgroup core got a fix on unified
  hierarchy and grew some effective css related interfaces which will be
  used for blkio support for writeback IO traffic which is currently
  being worked on"

* 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: implement cgroup_get_e_css()
  cgroup: add cgroup_subsys->css_e_css_changed()
  cgroup: add cgroup_subsys->css_released()
  cgroup: fix the async css offline wait logic in cgroup_subtree_control_write()
  cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write()
  cgroup: separate out cgroup_calc_child_subsys_mask() from cgroup_refresh_child_subsys_mask()
  cpuset: lock vs unlock typo
  cpuset: simplify cpuset_node_allowed API
  cpuset: convert callback_mutex to a spinlock
 2014-12-11 18:57:19 -08:00
Johannes Weiner
9edad6ea0f mm: move page->mem_cgroup bad page handling into generic code 
Now that the external page_cgroup data structure and its lookup is
gone, let the generic bad_page() check for page->mem_cgroup sanity.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:09 -08:00
Johannes Weiner
1306a85aed mm: embed the memcg pointer directly into struct page 
Memory cgroups used to have 5 per-page pointers.  To allow users to
disable that amount of overhead during runtime, those pointers were
allocated in a separate array, with a translation layer between them and
struct page.

There is now only one page pointer remaining: the memcg pointer, that
indicates which cgroup the page is associated with when charged.  The
complexity of runtime allocation and the runtime translation overhead is
no longer justified to save that *potential* 0.19% of memory.  With
CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding
after the page->private member and doesn't even increase struct page,
and then this patch actually saves space.  Remaining users that care can
still compile their kernels without CONFIG_MEMCG.

     text    data     bss     dec     hex     filename
  8828345 1725264  983040 11536649 b00909  vmlinux.old
  8827425 1725264  966656 11519345 afc571  vmlinux.new

[mhocko@suse.cz: update Documentation/cgroups/memory.txt]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:09 -08:00
Wei Yuan
26086de3fc mm: fix a spelling mistake 
Signed-off-by Wei Yuan <weiyuan.wei@huawei.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:08 -08:00
Vlastimil Babka
fdaf7f5c40 mm, compaction: more focused lru and pcplists draining 
The goal of memory compaction is to create high-order freepages through
page migration.  Page migration however puts pages on the per-cpu lru_add
cache, which is later flushed to per-cpu pcplists, and only after pcplists
are drained the pages can actually merge.  This can happen due to the
per-cpu caches becoming full through further freeing, or explicitly.

During direct compaction, it is useful to do the draining explicitly so
that pages merge as soon as possible and compaction can detect success
immediately and keep the latency impact at minimum.  However the current
implementation is far from ideal.  Draining is done only in
__alloc_pages_direct_compact(), after all zones were already compacted,
and the decisions to continue or stop compaction in individual zones was
done without the last batch of migrations being merged.  It is also
missing the draining of lru_add cache before the pcplists.

This patch moves the draining for direct compaction into compact_zone().
It adds the missing lru_cache draining and uses the newly introduced
single zone pcplists draining to reduce overhead and avoid impact on
unrelated zones.  Draining is only performed when it can actually lead to
merging of a page of desired order (passed by cc->order).  This means it
is only done when migration occurred in the previously scanned cc->order
aligned block(s) and the migration scanner is now pointing to the next
cc->order aligned block.

The patch has been tested with stress-highalloc benchmark from mmtests.
Although overal allocation success rates of the benchmark were not
affected, the number of detected compaction successes has doubled.  This
suggests that allocations were previously successful due to implicit
merging caused by background activity, making a later allocation attempt
succeed immediately, but not attributing the success to compaction.  Since
stress-highalloc always tries to allocate almost the whole memory, it
cannot show the improvement in its reported success rate metric.  However
after this patch, compaction should detect success and terminate earlier,
reducing the direct compaction latencies in a real scenario.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:06 -08:00
Vlastimil Babka
97d47a65be mm, compaction: simplify deferred compaction 
Since commit 53853e2d2b ("mm, compaction: defer each zone individually
instead of preferred zone"), compaction is deferred for each zone where
sync direct compaction fails, and reset where it succeeds.  However, it
was observed that for DMA zone compaction often appeared to succeed
while subsequent allocation attempt would not, due to different outcome
of watermark check.

In order to properly defer compaction in this zone, the candidate zone
has to be passed back to __alloc_pages_direct_compact() and compaction
deferred in the zone after the allocation attempt fails.

The large source of mismatch between watermark check in compaction and
allocation was the lack of alloc_flags and classzone_idx values in
compaction, which has been fixed in the previous patch.  So with this
problem fixed, we can simplify the code by removing the candidate_zone
parameter and deferring in __alloc_pages_direct_compact().

After this patch, the compaction activity during stress-highalloc
benchmark is still somewhat increased, but it's negligible compared to the
increase that occurred without the better watermark checking.  This
suggests that it is still possible to apparently succeed in compaction but
fail to allocate, possibly due to parallel allocation activity.

[akpm@linux-foundation.org: fix build]
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:06 -08:00
Vlastimil Babka
ebff398017 mm, compaction: pass classzone_idx and alloc_flags to watermark checking 
Compaction relies on zone watermark checks for decisions such as if it's
worth to start compacting in compaction_suitable() or whether compaction
should stop in compact_finished().  The watermark checks take
classzone_idx and alloc_flags parameters, which are related to the memory
allocation request.  But from the context of compaction they are currently
passed as 0, including the direct compaction which is invoked to satisfy
the allocation request, and could therefore know the proper values.

The lack of proper values can lead to mismatch between decisions taken
during compaction and decisions related to the allocation request.  Lack
of proper classzone_idx value means that lowmem_reserve is not taken into
account.  This has manifested (during recent changes to deferred
compaction) when DMA zone was used as fallback for preferred Normal zone.
compaction_suitable() without proper classzone_idx would think that the
watermarks are already satisfied, but watermark check in
get_page_from_freelist() would fail.  Because of this problem, deferring
compaction has extra complexity that can be removed in the following
patch.

The issue (not confirmed in practice) with missing alloc_flags is opposite
in nature.  For allocations that include ALLOC_HIGH, ALLOC_HIGHER or
ALLOC_CMA in alloc_flags (the last includes all MOVABLE allocations on
CMA-enabled systems) the watermark checking in compaction with 0 passed
will be stricter than in get_page_from_freelist().  In these cases
compaction might be running for a longer time than is really needed.

Another issue compaction_suitable() is that the check for "does the zone
need compaction at all?" comes only after the check "does the zone have
enough free free pages to succeed compaction".  The latter considers extra
pages for migration and can therefore in some situations fail and return
COMPACT_SKIPPED, although the high-order allocation would succeed and we
should return COMPACT_PARTIAL.

This patch fixes these problems by adding alloc_flags and classzone_idx to
struct compact_control and related functions involved in direct compaction
and watermark checking.  Where possible, all other callers of
compaction_suitable() pass proper values where those are known.  This is
currently limited to classzone_idx, which is sometimes known in kswapd
context.  However, the direct reclaim callers should_continue_reclaim()
and compaction_ready() do not currently know the proper values, so the
coordination between reclaim and compaction may still not be as accurate
as it could.  This can be fixed later, if it's shown to be an issue.

Additionaly the checks in compact_suitable() are reordered to address the
second issue described above.

The effect of this patch should be slightly better high-order allocation
success rates and/or less compaction overhead, depending on the type of
allocations and presence of CMA.  It allows simplifying deferred
compaction code in a followup patch.

When testing with stress-highalloc, there was some slight improvement
(which might be just due to variance) in success rates of non-THP-like
allocations.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:06 -08:00
Yu Zhao
ab1f306fa9 mm: verify compound order when freeing a page 
This allows us to catch the bug fixed in the previous patch (mm: free
compound page with correct order).

Here we also verify whether a page is tail page or not -- tail pages are
supposed to be freed along with their head, not by themselves.

Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:06 -08:00
Vlastimil Babka
510f550788 mm, cma: drain single zone pcplists 
CMA allocation drains pcplists so that pages can merge back to buddy
allocator.  Since it operates on a single zone, we can reduce the
pcplists drain to the single zone, which is now possible.

The change should make CMA allocations faster and not disturbing
unrelated pcplists anymore.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:05 -08:00
Vlastimil Babka
93481ff0e5 mm: introduce single zone pcplists drain 
The functions for draining per-cpu pages back to buddy allocators
currently always operate on all zones.  There are however several cases
where the drain is only needed in the context of a single zone, and
spilling other pcplists is a waste of time both due to the extra
spilling and later refilling.

This patch introduces new zone pointer parameter to drain_all_pages()
and changes the dummy parameter of drain_local_pages() to be also a zone
pointer.  When NULL is passed, the functions operate on all zones as
usual.  Passing a specific zone pointer reduces the work to the single
zone.

All callers are updated to pass the NULL pointer in this patch.
Conversion to single zone (where appropriate) is done in further
patches.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:05 -08:00
Anton Blanchard
f88dfff5f1 mm/page_alloc.c: convert boot printks without log level to pr_info 
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-12-10 17:41:05 -08:00
Joonsoo Kim
57cbc87e03 mm/debug-pagealloc: correct freepage accounting and order resetting 
One thing I did in this patch is fixing freepage accounting.  If we
clear guard page and link it onto isolate buddy list, we should not
increase freepage count.  This patch adds conditional branch to skip
counting in this case.  Without this patch, this overcounting happens
frequently if guard order is set and CMA is used.

Another thing fixed in this patch is the target to reset order.  In
__free_one_page(), we check the buddy page whether it is a guard page or
not.  And, if so, we should clear guard attribute on the buddy page and
reset order of it to 0.  But, current code resets original page's order
rather than buddy one's.  Maybe, this doesn't have any problem, because
whole merged page's order will be re-assigned soon.  But, it is better
to correct code.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:06 -08:00
Michal Nazarewicz
dae803e165 mm: alloc_contig_range: demote pages busy message from warn to info 
Having test_pages_isolated failure message as a warning confuses users
into thinking that it is more serious than it really is.  In reality, if
called via CMA, allocation will be retried so a single
test_pages_isolated failure does not prevent allocation from succeeding.

Demote the warning message to an info message and reformat it such that
the text "failed" does not appear and instead a less worrying "PFNS
busy" is used.

This message is trivially reproducible on a 10GB x86 machine on 3.16.y
kernels configured with CONFIG_DMA_CMA.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:05 -08:00
Joonsoo Kim
3c605096d3 mm/page_alloc: restrict max order of merging on isolated pageblock 
Current pageblock isolation logic could isolate each pageblock
individually.  This causes freepage accounting problem if freepage with
pageblock order on isolate pageblock is merged with other freepage on
normal pageblock.  We can prevent merging by restricting max order of
merging to pageblock order if freepage is on isolate pageblock.

A side-effect of this change is that there could be non-merged buddy
freepage even if finishing pageblock isolation, because undoing
pageblock isolation is just to move freepage from isolate buddy list to
normal buddy list rather than to consider merging.  So, the patch also
makes undoing pageblock isolation consider freepage merge.  When
un-isolation, freepage with more than pageblock order and it's buddy are
checked.  If they are on normal pageblock, instead of just moving, we
isolate the freepage and free it in order to get merged.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Heesub Shin <heesub.shin@samsung.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Ritesh Harjani <ritesh.list@gmail.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:05 -08:00
Joonsoo Kim
8f82b55dd5 mm/page_alloc: move freepage counting logic to __free_one_page() 
All the caller of __free_one_page() has similar freepage counting logic,
so we can move it to __free_one_page().  This reduce line of code and
help future maintenance.

This is also preparation step for "mm/page_alloc: restrict max order of
merging on isolated pageblock" which fix the freepage counting problem
on freepage with more than pageblock order.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Heesub Shin <heesub.shin@samsung.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Ritesh Harjani <ritesh.list@gmail.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:05 -08:00
Joonsoo Kim
51bb1a4093 mm/page_alloc: add freepage on isolate pageblock to correct buddy list 
In free_pcppages_bulk(), we use cached migratetype of freepage to
determine type of buddy list where freepage will be added.  This
information is stored when freepage is added to pcp list, so if
isolation of pageblock of this freepage begins after storing, this
cached information could be stale.  In other words, it has original
migratetype rather than MIGRATE_ISOLATE.

There are two problems caused by this stale information.

One is that we can't keep these freepages from being allocated.
Although this pageblock is isolated, freepage will be added to normal
buddy list so that it could be allocated without any restriction.  And
the other problem is incorrect freepage accounting.  Freepages on
isolate pageblock should not be counted for number of freepage.

Following is the code snippet in free_pcppages_bulk().

    /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
    __free_one_page(page, page_to_pfn(page), zone, 0, mt);
    trace_mm_page_pcpu_drain(page, 0, mt);
    if (likely(!is_migrate_isolate_page(page))) {
        __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
        if (is_migrate_cma(mt))
            __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
    }

As you can see above snippet, current code already handle second
problem, incorrect freepage accounting, by re-fetching pageblock
migratetype through is_migrate_isolate_page(page).

But, because this re-fetched information isn't used for
__free_one_page(), first problem would not be solved.  This patch try to
solve this situation to re-fetch pageblock migratetype before
__free_one_page() and to use it for __free_one_page().

In addition to move up position of this re-fetch, this patch use
optimization technique, re-fetching migratetype only if there is isolate
pageblock.  Pageblock isolation is rare event, so we can avoid
re-fetching in common case with this optimization.

This patch also correct migratetype of the tracepoint output.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Heesub Shin <heesub.shin@samsung.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Ritesh Harjani <ritesh.list@gmail.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:05 -08:00
Joonsoo Kim
ad53f92eb4 mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype 
Before describing bugs itself, I first explain definition of freepage.

 1. pages on buddy list are counted as freepage.
 2. pages on isolate migratetype buddy list are *not* counted as freepage.
 3. pages on cma buddy list are counted as CMA freepage, too.

Now, I describe problems and related patch.

Patch 1: There is race conditions on getting pageblock migratetype that
it results in misplacement of freepages on buddy list, incorrect
freepage count and un-availability of freepage.

Patch 2: Freepages on pcp list could have stale cached information to
determine migratetype of buddy list to go.  This causes misplacement of
freepages on buddy list and incorrect freepage count.

Patch 4: Merging between freepages on different migratetype of
pageblocks will cause freepages accouting problem.  This patch fixes it.

Without patchset [3], above problem doesn't happens on my CMA allocation
test, because CMA reserved pages aren't used at all.  So there is no
chance for above race.

With patchset [3], I did simple CMA allocation test and get below
result:

 - Virtual machine, 4 cpus, 1024 MB memory, 256 MB CMA reservation
 - run kernel build (make -j16) on background
 - 30 times CMA allocation(8MB * 30 = 240MB) attempts in 5 sec interval
 - Result: more than 5000 freepage count are missed

With patchset [3] and this patchset, I found that no freepage count are
missed so that I conclude that problems are solved.

On my simple memory offlining test, these problems also occur on that
environment, too.

This patch (of 4):

There are two paths to reach core free function of buddy allocator,
__free_one_page(), one is free_one_page()->__free_one_page() and the
other is free_hot_cold_page()->free_pcppages_bulk()->__free_one_page().
Each paths has race condition causing serious problems.  At first, this
patch is focused on first type of freepath.  And then, following patch
will solve the problem in second type of freepath.

In the first type of freepath, we got migratetype of freeing page
without holding the zone lock, so it could be racy.  There are two cases
of this race.

 1. pages are added to isolate buddy list after restoring orignal
    migratetype

    CPU1                                   CPU2

    get migratetype => return MIGRATE_ISOLATE
    call free_one_page() with MIGRATE_ISOLATE

                                grab the zone lock
                                unisolate pageblock
                                release the zone lock

    grab the zone lock
    call __free_one_page() with MIGRATE_ISOLATE
    freepage go into isolate buddy list,
    although pageblock is already unisolated

This may cause two problems.  One is that we can't use this page anymore
until next isolation attempt of this pageblock, because freepage is on
isolate buddy list.  The other is that freepage accouting could be wrong
due to merging between different buddy list.  Freepages on isolate buddy
list aren't counted as freepage, but ones on normal buddy list are
counted as freepage.  If merge happens, buddy freepage on normal buddy
list is inevitably moved to isolate buddy list without any consideration
of freepage accouting so it could be incorrect.

 2. pages are added to normal buddy list while pageblock is isolated.
    It is similar with above case.

This also may cause two problems.  One is that we can't keep these
freepages from being allocated.  Although this pageblock is isolated,
freepage would be added to normal buddy list so that it could be
allocated without any restriction.  And the other problem is same as
case 1, that it, incorrect freepage accouting.

This race condition would be prevented by checking migratetype again
with holding the zone lock.  Because it is somewhat heavy operation and
it isn't needed in common case, we want to avoid rechecking as much as
possible.  So this patch introduce new variable, nr_isolate_pageblock in
struct zone to check if there is isolated pageblock.  With this, we can
avoid to re-check migratetype in common case and do it only if there is
isolated pageblock or migratetype is MIGRATE_ISOLATE.  This solve above
mentioned problems.

Changes from v3:
Add one more check in free_one_page() that checks whether migratetype is
MIGRATE_ISOLATE or not. Without this, abovementioned case 1 could happens.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Heesub Shin <heesub.shin@samsung.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Ritesh Harjani <ritesh.list@gmail.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-11-13 16:17:05 -08:00
Vladimir Davydov
344736f29b cpuset: simplify cpuset_node_allowed API 
Current cpuset API for checking if a zone/node is allowed to allocate
from looks rather awkward. We have hardwall and softwall versions of
cpuset_node_allowed with the softwall version doing literally the same
as the hardwall version if __GFP_HARDWALL is passed to it in gfp flags.
If it isn't, the softwall version may check the given node against the
enclosing hardwall cpuset, which it needs to take the callback lock to
do.

Such a distinction was introduced by commit 02a0e53d82 ("cpuset:
rework cpuset_zone_allowed api"). Before, we had the only version with
the __GFP_HARDWALL flag determining its behavior. The purpose of the
commit was to avoid sleep-in-atomic bugs when someone would mistakenly
call the function without the __GFP_HARDWALL flag for an atomic
allocation. The suffixes introduced were intended to make the callers
think before using the function.

However, since the callback lock was converted from mutex to spinlock by
the previous patch, the softwall check function cannot sleep, and these
precautions are no longer necessary.

So let's simplify the API back to the single check.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
 2014-10-27 11:15:27 -04:00
Michal Hocko
5695be142e OOM, PM: OOM killed task shouldn't escape PM suspend 
PM freezer relies on having all tasks frozen by the time devices are
getting frozen so that no task will touch them while they are getting
frozen. But OOM killer is allowed to kill an already frozen task in
order to handle OOM situtation. In order to protect from late wake ups
OOM killer is disabled after all tasks are frozen. This, however, still
keeps a window open when a killed task didn't manage to die by the time
freeze_processes finishes.

Reduce the race window by checking all tasks after OOM killer has been
disabled. This is still not race free completely unfortunately because
oom_killer_disable cannot stop an already ongoing OOM killer so a task
might still wake up from the fridge and get killed without
freeze_processes noticing. Full synchronization of OOM and freezer is,
however, too heavy weight for this highly unlikely case.

Introduce and check oom_kills counter which gets incremented early when
the allocator enters __alloc_pages_may_oom path and only check all the
tasks if the counter changes during the freezing attempt. The counter
is updated so early to reduce the race window since allocator checked
oom_killer_disabled which is set by PM-freezing code. A false positive
will push the PM-freezer into a slow path but that is not a big deal.

Changes since v1
- push the re-check loop out of freeze_processes into
  check_frozen_processes and invert the condition to make the code more
  readable as per Rafael

Fixes: f660daac47 (oom: thaw threads if oom killed thread is frozen before deferring)
Cc: 3.2+ <stable@vger.kernel.org> # 3.2+
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2014-10-21 23:44:21 +02:00
Linus Torvalds
df133e8fa8 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 
Pull x86 mm updates from Ingo Molnar:
 "This tree includes the following changes:

   - fix memory hotplug
   - fix hibernation bootup memory layout assumptions
   - fix hyperv numa guest kernel messages
   - remove dead code
   - update documentation"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Update memory map description to list hypervisor-reserved area
  x86/mm, hibernate: Do not assume the first e820 area to be RAM
  x86/mm/numa: Drop dead code and rename setup_node_data() to setup_alloc_data()
  x86/mm/hotplug: Modify PGD entry when removing memory
  x86/mm/hotplug: Pass sync_global_pgds() a correct argument in remove_pagetable()
  x86: Remove set_pmd_pfn
 2014-10-14 02:22:41 +02:00
Sasha Levin
82742a3a51 mm: move debug code out of page_alloc.c 
dump_page() and dump_vma() are not specific to page_alloc.c, move them out
so page_alloc.c won't turn into the unofficial debug repository.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:58 -04:00
Mel Gorman
3193913ce6 mm: page_alloc: default node-ordering on 64-bit NUMA, zone-ordering on 32-bit 
Zones are allocated by the page allocator in either node or zone order.
Node ordering is preferred in terms of locality and is applied
automatically in one of three cases:

  1. If a node has only low memory

  2. If DMA/DMA32 is a high percentage of memory

  3. If low memory on a single node is greater than 70% of the node size

Otherwise zone ordering is used to preserve low memory for devices that
require it.  Unfortunately a consequence of this is that applications
running on a machine with balanced NUMA nodes will experience different
performance characteristics depending on which node they happen to start
from.

The point of zone ordering is to protect lower zones for devices that
require DMA/DMA32 memory.  When NUMA was first introduced, this was
critical as 32-bit NUMA machines existed and exhausting low memory
triggered OOMs easily as so many allocations required low memory.  On
64-bit machines the primary concern is devices that are 32-bit only which
is less severe than the low memory exhaustion problem on 32-bit NUMA.  It
seems there are really few devices that depends on it.

AGP -- I assume this is getting more rare but even then I think the allocations
	happen early in boot time where lowmem pressure is less of a problem

DRM -- If the device is 32-bit only then there may be low pressure. I didn't
	evaluate these in detail but it looks like some of these are mobile
	graphics card. Not many NUMA laptops out there. DRM folk should know
	better though.

Some TV cards -- Much demand for 32-bit capable TV cards on NUMA machines?

B43 wireless card -- again not really a NUMA thing.

I cannot find a good reason to incur a performance penalty on all 64-bit NUMA
machines in case someone throws a brain damanged TV or graphics card in there.
This patch defaults to node-ordering on 64-bit NUMA machines. I was tempted
to make it default everywhere but I understand that some embedded arches may
be using 32-bit NUMA where I cannot predict the consequences.

The performance impact depends on the workload and the characteristics of the
machine and the machine I tested on had a large Normal zone on node 0 so the
impact is within the noise for the majority of tests. The allocation stats
show more allocation requests were from DMA32 and local node. Running SpecJBB
with multiple JVMs and automatic NUMA balancing disabled the results were

specjbb
                     3.17.0-rc2            3.17.0-rc2
                        vanilla        nodeorder-v1r1
Min    1      29534.00 (  0.00%)     30020.00 (  1.65%)
Min    10    115717.00 (  0.00%)    134038.00 ( 15.83%)
Min    19    109718.00 (  0.00%)    114186.00 (  4.07%)
Min    28    104459.00 (  0.00%)    103639.00 ( -0.78%)
Min    37     98245.00 (  0.00%)    103756.00 (  5.61%)
Min    46     97198.00 (  0.00%)     96197.00 ( -1.03%)
Mean   1      30953.25 (  0.00%)     31917.75 (  3.12%)
Mean   10    124432.50 (  0.00%)    140904.00 ( 13.24%)
Mean   19    116033.50 (  0.00%)    119294.75 (  2.81%)
Mean   28    108365.25 (  0.00%)    106879.50 ( -1.37%)
Mean   37    102984.75 (  0.00%)    106924.25 (  3.83%)
Mean   46    100783.25 (  0.00%)    105368.50 (  4.55%)
Stddev 1       1260.38 (  0.00%)      1109.66 ( 11.96%)
Stddev 10      7434.03 (  0.00%)      5171.91 ( 30.43%)
Stddev 19      8453.84 (  0.00%)      5309.59 ( 37.19%)
Stddev 28      4184.55 (  0.00%)      2906.63 ( 30.54%)
Stddev 37      5409.49 (  0.00%)      3192.12 ( 40.99%)
Stddev 46      4521.95 (  0.00%)      7392.52 (-63.48%)
Max    1      32738.00 (  0.00%)     32719.00 ( -0.06%)
Max    10    136039.00 (  0.00%)    148614.00 (  9.24%)
Max    19    130566.00 (  0.00%)    127418.00 ( -2.41%)
Max    28    115404.00 (  0.00%)    111254.00 ( -3.60%)
Max    37    112118.00 (  0.00%)    111732.00 ( -0.34%)
Max    46    108541.00 (  0.00%)    116849.00 (  7.65%)
TPut   1     123813.00 (  0.00%)    127671.00 (  3.12%)
TPut   10    497730.00 (  0.00%)    563616.00 ( 13.24%)
TPut   19    464134.00 (  0.00%)    477179.00 (  2.81%)
TPut   28    433461.00 (  0.00%)    427518.00 ( -1.37%)
TPut   37    411939.00 (  0.00%)    427697.00 (  3.83%)
TPut   46    403133.00 (  0.00%)    421474.00 (  4.55%)

                            3.17.0-rc2  3.17.0-rc2
                               vanillanodeorder-v1r1
DMA allocs                           0           0
DMA32 allocs                        57     1491992
Normal allocs                 32543566    30026383
Movable allocs                       0           0
Direct pages scanned                 0           0
Kswapd pages scanned                 0           0
Kswapd pages reclaimed               0           0
Direct pages reclaimed               0           0
Kswapd efficiency                 100%        100%
Kswapd velocity                  0.000       0.000
Direct efficiency                 100%        100%
Direct velocity                  0.000       0.000
Percentage direct scans             0%          0%
Zone normal velocity             0.000       0.000
Zone dma32 velocity              0.000       0.000
Zone dma velocity                0.000       0.000
THP fault alloc                  55164       52987
THP collapse alloc                 139         147
THP splits                          26          21
NUMA alloc hit                 4169066     4250692
NUMA alloc miss                      0           0

Note that there were more DMA32 allocations with the patch applied.  In this
particular case there was no difference in numa_hit and numa_miss. The
expectation is that DMA32 was being used at the low watermark instead of
falling into the slow path. kswapd was not woken but it's not worken for
THP allocations.

On 32-bit, this patch defaults to zone-ordering as low memory depletion
can be a serious problem on 32-bit large memory machines. If the default
ordering was node then processes on node 0 will deplete the Normal zone
due to normal activity.  The problem is worse if CONFIG_HIGHPTE is not
set. If combined with large amounts of dirty/writeback pages in Normal
zone then there is also a high risk of OOM. The heuristics are removed
as it's not clear they were ever important on 32-bit. They were only
relevant for setting node-ordering on 64-bit.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:58 -04:00
Mel Gorman
97ee4ba7cb mm: page_alloc: Make paranoid check in move_freepages a VM_BUG_ON 
Since 2.6.24 there has been a paranoid check in move_freepages that looks
up the zone of two pages.  This is a very slow path and the only time I've
seen this bug trigger recently is when memory initialisation was broken
during patch development.  Despite the fact it's a slow path, this patch
converts the check to a VM_BUG_ON anyway as it has served its purpose by
now.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:58 -04:00
Johannes Weiner
5705465174 mm: clean up zone flags 
Page reclaim tests zone_is_reclaim_dirty(), but the site that actually
sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending the
reader through layers indirection just to track down a simple bit.

Remove all zone flag wrappers and just use bitops against zone->flags
directly.  It's just as readable and the lines are barely any longer.

Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK, and
remove the zone_flags_t typedef.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:57 -04:00
Weijie Yang
7ade3c9972 mm: page_alloc: avoid wakeup kswapd on the unintended node 
When entering the page_alloc slowpath, we wakeup kswapd on every pgdat
according to the zonelist and high_zoneidx.  However, this doesn't take
nodemask into account, and could prematurely wakeup kswapd on some
unintended nodes.

This patch uses for_each_zone_zonelist_nodemask() instead of
for_each_zone_zonelist() in wake_all_kswapds() to avoid the above
situation.

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:57 -04:00
Sasha Levin
0bf5513978 mm: introduce dump_vma 
Introduce a helper to dump information about a VMA, this also makes
dump_page_flags more generic and re-uses that so the output looks very
similar to dump_page:

[   61.903437] vma ffff88070f88be00 start 00007fff25970000 end 00007fff25992000
[   61.903437] next ffff88070facd600 prev ffff88070face400 mm ffff88070fade000
[   61.903437] prot 8000000000000025 anon_vma ffff88070fa1e200 vm_ops           (null)
[   61.903437] pgoff 7ffffffdd file           (null) private_data           (null)
[   61.909129] flags: 0x100173(read|write|mayread|maywrite|mayexec|growsdown|account)

[akpm@linux-foundation.org: make dump_vma() require CONFIG_DEBUG_VM]
[swarren@nvidia.com: fix dump_vma() compilation]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:57 -04:00
David Rientjes
43e7a34d26 mm: rename allocflags_to_migratetype for clarity 
The page allocator has gfp flags (like __GFP_WAIT) and alloc flags (like
ALLOC_CPUSET) that have separate semantics.

The function allocflags_to_migratetype() actually takes gfp flags, not
alloc flags, and returns a migratetype.  Rename it to
gfpflags_to_migratetype().

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:55 -04:00
Vlastimil Babka
1f9efdef4f mm, compaction: khugepaged should not give up due to need_resched() 
Async compaction aborts when it detects zone lock contention or
need_resched() is true.  David Rientjes has reported that in practice,
most direct async compactions for THP allocation abort due to
need_resched().  This means that a second direct compaction is never
attempted, which might be OK for a page fault, but khugepaged is intended
to attempt a sync compaction in such case and in these cases it won't.

This patch replaces "bool contended" in compact_control with an int that
distinguishes between aborting due to need_resched() and aborting due to
lock contention.  This allows propagating the abort through all compaction
functions as before, but passing the abort reason up to
__alloc_pages_slowpath() which decides when to continue with direct
reclaim and another compaction attempt.

Another problem is that try_to_compact_pages() did not act upon the
reported contention (both need_resched() or lock contention) immediately
and would proceed with another zone from the zonelist.  When
need_resched() is true, that means initializing another zone compaction,
only to check again need_resched() in isolate_migratepages() and aborting.
 For zone lock contention, the unintended consequence is that the lock
contended status reported back to the allocator is detrmined from the last
zone where compaction was attempted, which is rather arbitrary.

This patch fixes the problem in the following way:
- async compaction of a zone aborting due to need_resched() or fatal signal
  pending means that further zones should not be tried. We report
  COMPACT_CONTENDED_SCHED to the allocator.
- aborting zone compaction due to lock contention means we can still try
  another zone, since it has different set of locks. We report back
  COMPACT_CONTENDED_LOCK only if *all* zones where compaction was attempted,
  it was aborted due to lock contention.

As a result of these fixes, khugepaged will proceed with second sync
compaction as intended, when the preceding async compaction aborted due to
need_resched().  Page fault compactions aborting due to need_resched()
will spare some cycles previously wasted by initializing another zone
compaction only to abort again.  Lock contention will be reported only
when compaction in all zones aborted due to lock contention, and therefore
it's not a good idea to try again after reclaim.

In stress-highalloc from mmtests configured to use __GFP_NO_KSWAPD, this
has improved number of THP collapse allocations by 10%, which shows
positive effect on khugepaged.  The benchmark's success rates are
unchanged as it is not recognized as khugepaged.  Numbers of compact_stall
and compact_fail events have however decreased by 20%, with
compact_success still a bit improved, which is good.  With benchmark
configured not to use __GFP_NO_KSWAPD, there is 6% improvement in THP
collapse allocations, and only slight improvement in stalls and failures.

[akpm@linux-foundation.org: fix warnings]
Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:54 -04:00
Vlastimil Babka
edc2ca6124 mm, compaction: move pageblock checks up from isolate_migratepages_range() 
isolate_migratepages_range() is the main function of the compaction
scanner, called either on a single pageblock by isolate_migratepages()
during regular compaction, or on an arbitrary range by CMA's
__alloc_contig_migrate_range().  It currently perfoms two pageblock-wide
compaction suitability checks, and because of the CMA callpath, it tracks
if it crossed a pageblock boundary in order to repeat those checks.

However, closer inspection shows that those checks are always true for CMA:
- isolation_suitable() is true because CMA sets cc->ignore_skip_hint to true
- migrate_async_suitable() check is skipped because CMA uses sync compaction

We can therefore move the compaction-specific checks to
isolate_migratepages() and simplify isolate_migratepages_range().
Furthermore, we can mimic the freepage scanner family of functions, which
has isolate_freepages_block() function called both by compaction from
isolate_freepages() and by CMA from isolate_freepages_range(), where each
use-case adds own specific glue code.  This allows further code
simplification.

Thus, we rename isolate_migratepages_range() to
isolate_migratepages_block() and limit its functionality to a single
pageblock (or its subset).  For CMA, a new different
isolate_migratepages_range() is created as a CMA-specific wrapper for the
_block() function.  The checks specific to compaction are moved to
isolate_migratepages().  As part of the unification of these two families
of functions, we remove the redundant zone parameter where applicable,
since zone pointer is already passed in cc->zone.

Furthermore, going back to compact_zone() and compact_finished() when
pageblock is found unsuitable (now by isolate_migratepages()) is wasteful
- the checks are meant to skip pageblocks quickly.  The patch therefore
also introduces a simple loop into isolate_migratepages() so that it does
not return immediately on failed pageblock checks, but keeps going until
isolate_migratepages_range() gets called once.  Similarily to
isolate_freepages(), the function periodically checks if it needs to
reschedule or abort async compaction.

[iamjoonsoo.kim@lge.com: fix isolated page counting bug in compaction]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:54 -04:00
Vlastimil Babka
98dd3b48a7 mm, compaction: do not count compact_stall if all zones skipped compaction 
The compact_stall vmstat counter counts the number of allocations stalled
by direct compaction.  It does not count when all attempted zones had
deferred compaction, but it does count when all zones skipped compaction.
The skipping is decided based on very early check of
compaction_suitable(), based on watermarks and memory fragmentation.
Therefore it makes sense not to count skipped compactions as stalls.
Moreover, compact_success or compact_fail is also already not being
counted when compaction was skipped, so this patch changes the
compact_stall counting to match the other two.

Additionally, restructure __alloc_pages_direct_compact() code for better
readability.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:53 -04:00
Vlastimil Babka
53853e2d2b mm, compaction: defer each zone individually instead of preferred zone 
When direct sync compaction is often unsuccessful, it may become deferred
for some time to avoid further useless attempts, both sync and async.
Successful high-order allocations un-defer compaction, while further
unsuccessful compaction attempts prolong the compaction deferred period.

Currently the checking and setting deferred status is performed only on
the preferred zone of the allocation that invoked direct compaction.  But
compaction itself is attempted on all eligible zones in the zonelist, so
the behavior is suboptimal and may lead both to scenarios where 1)
compaction is attempted uselessly, or 2) where it's not attempted despite
good chances of succeeding, as shown on the examples below:

1) A direct compaction with Normal preferred zone failed and set
   deferred compaction for the Normal zone.  Another unrelated direct
   compaction with DMA32 as preferred zone will attempt to compact DMA32
   zone even though the first compaction attempt also included DMA32 zone.

   In another scenario, compaction with Normal preferred zone failed to
   compact Normal zone, but succeeded in the DMA32 zone, so it will not
   defer compaction.  In the next attempt, it will try Normal zone which
   will fail again, instead of skipping Normal zone and trying DMA32
   directly.

2) Kswapd will balance DMA32 zone and reset defer status based on
   watermarks looking good.  A direct compaction with preferred Normal
   zone will skip compaction of all zones including DMA32 because Normal
   was still deferred.  The allocation might have succeeded in DMA32, but
   won't.

This patch makes compaction deferring work on individual zone basis
instead of preferred zone.  For each zone, it checks compaction_deferred()
to decide if the zone should be skipped.  If watermarks fail after
compacting the zone, defer_compaction() is called.  The zone where
watermarks passed can still be deferred when the allocation attempt is
unsuccessful.  When allocation is successful, compaction_defer_reset() is
called for the zone containing the allocated page.  This approach should
approximate calling defer_compaction() only on zones where compaction was
attempted and did not yield allocated page.  There might be corner cases
but that is inevitable as long as the decision to stop compacting dues not
guarantee that a page will be allocated.

Due to a new COMPACT_DEFERRED return value, some functions relying
implicitly on COMPACT_SKIPPED = 0 had to be updated, with comments made
more accurate.  The did_some_progress output parameter of
__alloc_pages_direct_compact() is removed completely, as the caller
actually does not use it after compaction sets it - it is only considered
when direct reclaim sets it.

During testing on a two-node machine with a single very small Normal zone
on node 1, this patch has improved success rates in stress-highalloc
mmtests benchmark.  The success here were previously made worse by commit
3a025760fc ("mm: page_alloc: spill to remote nodes before waking
kswapd") as kswapd was no longer resetting often enough the deferred
compaction for the Normal zone, and DMA32 zones on both nodes were thus
not considered for compaction.  On different machine, success rates were
improved with __GFP_NO_KSWAPD allocations.

[akpm@linux-foundation.org: fix CONFIG_COMPACTION=n build]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:53 -04:00
Vlastimil Babka
21bb9bd194 mm: page_alloc: determine migratetype only once 
The check for ALLOC_CMA in __alloc_pages_nodemask() derives migratetype
from gfp_mask in each retry pass, although the migratetype variable
already has the value determined and it does not change.  Use the variable
and perform the check only once.  Also convert #ifdef CONFIG_CMA to
IS_ENABLED.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:53 -04:00
Joonsoo Kim
ad2c814441 topology: add support for node_to_mem_node() to determine the fallback node 
Anton noticed (http://www.spinics.net/lists/linux-mm/msg67489.html) that
on ppc LPARs with memoryless nodes, a large amount of memory was consumed
by slabs and was marked unreclaimable.  He tracked it down to slab
deactivations in the SLUB core when we allocate remotely, leading to poor
efficiency always when memoryless nodes are present.

After much discussion, Joonsoo provided a few patches that help
significantly.  They don't resolve the problem altogether:

 - memory hotplug still needs testing, that is when a memoryless node
   becomes memory-ful, we want to dtrt
 - there are other reasons for going off-node than memoryless nodes,
   e.g., fully exhausted local nodes

Neither case is resolved with this series, but I don't think that should
block their acceptance, as they can be explored/resolved with follow-on
patches.

The series consists of:

[1/3] topology: add support for node_to_mem_node() to determine the
      fallback node

[2/3] slub: fallback to node_to_mem_node() node if allocating on
      memoryless node

      - Joonsoo's patches to cache the nearest node with memory for each
        NUMA node

[3/3] Partial revert of 81c98869fa (""kthread: ensure locality of
      task_struct allocations")

 - At Tejun's request, keep the knowledge of memoryless node fallback
   to the allocator core.

This patch (of 3):

We need to determine the fallback node in slub allocator if the allocation
target node is memoryless node.  Without it, the SLUB wrongly select the
node which has no memory and can't use a partial slab, because of node
mismatch.  Introduced function, node_to_mem_node(X), will return a node Y
with memory that has the nearest distance.  If X is memoryless node, it
will return nearest distance node, but, if X is normal node, it will
return itself.

We will use this function in following patch to determine the fallback
node.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Han Pingtian <hanpt@linux.vnet.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Anton Blanchard <anton@samba.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-10-09 22:25:51 -04:00
Johannes Weiner
abe5f97291 mm: page_alloc: fix zone allocation fairness on UP 
The zone allocation batches can easily underflow due to higher-order
allocations or spills to remote nodes.  On SMP that's fine, because
underflows are expected from concurrency and dealt with by returning 0.
But on UP, zone_page_state will just return a wrapped unsigned long,
which will get past the <= 0 check and then consider the zone eligible
until its watermarks are hit.

Commit 3a025760fc ("mm: page_alloc: spill to remote nodes before
waking kswapd") already made the counter-resetting use
atomic_long_read() to accomodate underflows from remote spills, but it
didn't go all the way with it.

Make it clear that these batches are expected to go negative regardless
of concurrency, and use atomic_long_read() everywhere.

Fixes: 81c0a2bb51 ("mm: page_alloc: fair zone allocator policy")
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
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>
 2014-10-02 16:28:44 -07:00
Luiz Capitulino
8b375f64dc x86/mm/numa: Drop dead code and rename setup_node_data() to setup_alloc_data() 
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>
 2014-09-16 08:55:10 +02:00
David Rientjes
8fe780484d mm, thp: restructure thp avoidance of light synchronous migration 
__GFP_NO_KSWAPD, once the way to determine if an allocation was for thp
or not, has gained more users.  Their use is not necessarily wrong, they
are trying to do a memory allocation that can easily fail without
disturbing kswapd, so the bit has gained additional usecases.

This restructures the check to determine whether MIGRATE_SYNC_LIGHT
should be used for memory compaction in the page allocator.  Rather than
testing solely for __GFP_NO_KSWAPD, test for all bits that must be set
for thp allocations.

This also moves the check to be done only after the page allocator is
aborted for deferred or contended memory compaction since setting
migration_mode for this case is pointless.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
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>
 2014-08-06 18:01:21 -07:00
David Rientjes
e972a070e2 mm, oom: rename zonelist locking functions 
try_set_zonelist_oom() and clear_zonelist_oom() are not named properly
to imply that they require locking semantics to avoid out_of_memory()
being reordered.

zone_scan_lock is required for both functions to ensure that there is
proper locking synchronization.

Rename try_set_zonelist_oom() to oom_zonelist_trylock() and rename
clear_zonelist_oom() to oom_zonelist_unlock() to imply there is proper
locking semantics.

At the same time, convert oom_zonelist_trylock() to return bool instead
of int since only success and failure are tested.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2014-08-06 18:01:21 -07:00