Commit Graph

7975 Commits

Author SHA1 Message Date
Kirill A. Shutemov
1592eef015 mm: add debugfs tunable for fault_around_order
Let's allow people to tweak faultaround at runtime.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:53 -07:00
Kirill A. Shutemov
99e3e53f4e mm: cleanup size checks in filemap_fault() and filemap_map_pages()
Minor cleanups:
 - 'size' variable is now in bytes, not pages;
 - use round_up(): it should be easier to read.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:53 -07:00
Kirill A. Shutemov
f1820361f8 mm: implement ->map_pages for page cache
filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.

It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:53 -07:00
Kirill A. Shutemov
8c6e50b029 mm: introduce vm_ops->map_pages()
Here's new version of faultaround patchset.  It took a while to tune it
and collect performance data.

First patch adds new callback ->map_pages to vm_operations_struct.

->map_pages() is called when VM asks to map easy accessible pages.
Filesystem should find and map pages associated with offsets from
"pgoff" till "max_pgoff".  ->map_pages() is called with page table
locked and must not block.  If it's not possible to reach a page without
blocking, filesystem should skip it.  Filesystem should use do_set_pte()
to setup page table entry.  Pointer to entry associated with offset
"pgoff" is passed in "pte" field in vm_fault structure.  Pointers to
entries for other offsets should be calculated relative to "pte".

Currently VM use ->map_pages only on read page fault path.  We try to
map FAULT_AROUND_PAGES a time.  FAULT_AROUND_PAGES is 16 for now.
Performance data for different FAULT_AROUND_ORDER is below.

TODO:
 - implement ->map_pages() for shmem/tmpfs;
 - modify get_user_pages() to be able to use ->map_pages() and implement
   mmap(MAP_POPULATE|MAP_NONBLOCK) on top.

=========================================================================
Tested on 4-socket machine (120 threads) with 128GiB of RAM.

Few real-world workloads. The sweet spot for FAULT_AROUND_ORDER here is
somewhere between 3 and 5. Let's say 4 :)

Linux build (make -j60)
FAULT_AROUND_ORDER		Baseline	1		3		4		5		7		9
	minor-faults		283,301,572	247,151,987	212,215,789	204,772,882	199,568,944	194,703,779	193,381,485
	time, seconds		151.227629483	153.920996480	151.356125472	150.863792049	150.879207877	151.150764954	151.450962358
Linux rebuild (make -j60)
FAULT_AROUND_ORDER		Baseline	1		3		4		5		7		9
	minor-faults		5,396,854	4,148,444	2,855,286	2,577,282	2,361,957	2,169,573	2,112,643
	time, seconds		27.404543757	27.559725591	27.030057426	26.855045126	26.678618635	26.974523490	26.761320095
Git test suite (make -j60 test)
FAULT_AROUND_ORDER		Baseline	1		3		4		5		7		9
	minor-faults		129,591,823	99,200,751	66,106,718	57,606,410	51,510,808	45,776,813	44,085,515
	time, seconds		66.087215026	64.784546905	64.401156567	65.282708668	66.034016829	66.793780811	67.237810413

Two synthetic tests: access every word in file in sequential/random order.
It doesn't improve much after FAULT_AROUND_ORDER == 4.

Sequential access 16GiB file
FAULT_AROUND_ORDER		Baseline	1		3		4		5		7		9
 1 thread
	minor-faults		4,195,437	2,098,275	525,068		262,251		131,170		32,856		8,282
	time, seconds		7.250461742	6.461711074	5.493859139	5.488488147	5.707213983	5.898510832	5.109232856
 8 threads
	minor-faults		33,557,540	16,892,728	4,515,848	2,366,999	1,423,382	442,732		142,339
	time, seconds		16.649304881	9.312555263	6.612490639	6.394316732	6.669827501	6.75078944	6.371900528
 32 threads
	minor-faults		134,228,222	67,526,810	17,725,386	9,716,537	4,763,731	1,668,921	537,200
	time, seconds		49.164430543	29.712060103	12.938649729	10.175151004	11.840094583	9.594081325	9.928461797
 60 threads
	minor-faults		251,687,988	126,146,952	32,919,406	18,208,804	10,458,947	2,733,907	928,217
	time, seconds		86.260656897	49.626551828	22.335007632	17.608243696	16.523119035	16.339489186	16.326390902
 120 threads
	minor-faults		503,352,863	252,939,677	67,039,168	35,191,827	19,170,091	4,688,357	1,471,862
	time, seconds		124.589206333	79.757867787	39.508707872	32.167281632	29.972989292	28.729834575	28.042251622
Random access 1GiB file
 1 thread
	minor-faults		262,636		132,743		34,369		17,299		8,527		3,451		1,222
	time, seconds		15.351890914	16.613802482	16.569227308	15.179220992	16.557356122	16.578247824	15.365266994
 8 threads
	minor-faults		2,098,948	1,061,871	273,690		154,501		87,110		25,663		7,384
	time, seconds		15.040026343	15.096933500	14.474757288	14.289129964	14.411537468	14.296316837	14.395635804
 32 threads
	minor-faults		8,390,734	4,231,023	1,054,432	528,847		269,242		97,746		26,881
	time, seconds		20.430433109	21.585235358	22.115062928	14.872878951	14.880856305	14.883370649	14.821261690
 60 threads
	minor-faults		15,733,258	7,892,809	1,973,393	988,266		594,789		164,994		51,691
	time, seconds		26.577302548	25.692397770	18.728863715	20.153026398	21.619101933	17.745086260	17.613215273
 120 threads
	minor-faults		31,471,111	15,816,616	3,959,209	1,978,685	1,008,299	264,635		96,010
	time, seconds		41.835322703	40.459786095	36.085306105	35.313894834	35.814445675	36.552633793	34.289210594

Touch only one page in page table in 16GiB file
FAULT_AROUND_ORDER		Baseline	1		3		4		5		7		9
 1 thread
	minor-faults		8,372		8,324		8,270		8,260		8,249		8,239		8,237
	time, seconds		0.039892712	0.045369149	0.051846126	0.063681685	0.079095975	0.17652406	0.541213386
 8 threads
	minor-faults		65,731		65,681		65,628		65,620		65,608		65,599		65,596
	time, seconds		0.124159196	0.488600638	0.156854426	0.191901957	0.242631486	0.543569456	1.677303984
 32 threads
	minor-faults		262,388		262,341		262,285		262,276		262,266		262,257		263,183
	time, seconds		0.452421421	0.488600638	0.565020946	0.648229739	0.789850823	1.651584361	5.000361559
 60 threads
	minor-faults		491,822		491,792		491,723		491,711		491,701		491,691		491,825
	time, seconds		0.763288616	0.869620515	0.980727360	1.161732354	1.466915814	3.04041448	9.308612938
 120 threads
	minor-faults		983,466		983,655		983,366		983,372		983,363		984,083		984,164
	time, seconds		1.595846553	1.667902182	2.008959376	2.425380942	2.941368804	5.977807890	18.401846125

This patch (of 2):

Introduce new vm_ops callback ->map_pages() and uses it for mapping easy
accessible pages around fault address.

On read page fault, if filesystem provides ->map_pages(), we try to map up
to FAULT_AROUND_PAGES pages around page fault address in hope to reduce
number of minor page faults.

We call ->map_pages first and use ->fault() as fallback if page by the
offset is not ready to be mapped (cold page cache or something).

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:52 -07:00
Kirill A. Shutemov
9164550ecd mm: disable split page table lock for !MMU
There's no reason to enable split page table lock if don't have page
tables.

It also triggers build error at least on ARM since we don't define
pmd_page() for !MMU.

  In file included from arch/arm/kernel/asm-offsets.c:14:0:
  include/linux/mm.h: In function 'pte_lockptr':
  include/linux/mm.h:1392:2: error: implicit declaration of function 'pmd_page' [-Werror=implicit-function-declaration]
  include/linux/mm.h:1392:2: warning: passing argument 1 of 'ptlock_ptr' makes pointer from integer without a cast [enabled by default]
  include/linux/mm.h:1384:27: note: expected 'struct page *' but argument is of type 'int'

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:52 -07:00
Alex Thorlton
1e1836e84f mm: revert "thp: make MADV_HUGEPAGE check for mm->def_flags"
The main motivation behind this patch is to provide a way to disable THP
for jobs where the code cannot be modified, and using a malloc hook with
madvise is not an option (i.e.  statically allocated data).  This patch
allows us to do just that, without affecting other jobs running on the
system.

We need to do this sort of thing for jobs where THP hurts performance,
due to the possibility of increased remote memory accesses that can be
created by situations such as the following:

When you touch 1 byte of an untouched, contiguous 2MB chunk, a THP will
be handed out, and the THP will be stuck on whatever node the chunk was
originally referenced from.  If many remote nodes need to do work on
that same chunk, they'll be making remote accesses.

With THP disabled, 4K pages can be handed out to separate nodes as
they're needed, greatly reducing the amount of remote accesses to
memory.

This patch is based on some of my work combined with some
suggestions/patches given by Oleg Nesterov.  The main goal here is to
add a prctl switch to allow us to disable to THP on a per mm_struct
basis.

Here's a bit of test data with the new patch in place...

First with the flag unset:

  # perf stat -a ./prctl_wrapper_mmv3 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
  Setting thp_disabled for this task...
  thp_disable: 0
  Set thp_disabled state to 0
  Process pid = 18027

                                                                                                                       PF/
                                  MAX        MIN                                  TOTCPU/      TOT_PF/   TOT_PF/     WSEC/
  TYPE:               CPUS       WALL       WALL        SYS     USER     TOTCPU       CPU     WALL_SEC   SYS_SEC       CPU   NODES
   512      1.120      0.060      0.000    0.110      0.110     0.000    28571428864 -9223372036854775808  55803572      23

   Performance counter stats for './prctl_wrapper_mmv3_hack 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':

    273719072.841402 task-clock                #  641.026 CPUs utilized           [100.00%]
           1,008,986 context-switches          #    0.000 M/sec                   [100.00%]
               7,717 CPU-migrations            #    0.000 M/sec                   [100.00%]
           1,698,932 page-faults               #    0.000 M/sec
  355,222,544,890,379 cycles                   #    1.298 GHz                     [100.00%]
  536,445,412,234,588 stalled-cycles-frontend  #  151.02% frontend cycles idle    [100.00%]
  409,110,531,310,223 stalled-cycles-backend   #  115.17% backend  cycles idle    [100.00%]
  148,286,797,266,411 instructions             #    0.42  insns per cycle
                                               #    3.62  stalled cycles per insn [100.00%]
  27,061,793,159,503 branches                  #   98.867 M/sec                   [100.00%]
       1,188,655,196 branch-misses             #    0.00% of all branches

       427.001706337 seconds time elapsed

Now with the flag set:

  # perf stat -a ./prctl_wrapper_mmv3 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
  Setting thp_disabled for this task...
  thp_disable: 1
  Set thp_disabled state to 1
  Process pid = 144957

                                                                                                                       PF/
                                  MAX        MIN                                  TOTCPU/      TOT_PF/   TOT_PF/     WSEC/
  TYPE:               CPUS       WALL       WALL        SYS     USER     TOTCPU       CPU     WALL_SEC   SYS_SEC       CPU   NODES
   512      0.620      0.260      0.250    0.320      0.570     0.001    51612901376 128000000000 100806448      23

   Performance counter stats for './prctl_wrapper_mmv3_hack 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':

    138789390.540183 task-clock                #  641.959 CPUs utilized           [100.00%]
             534,205 context-switches          #    0.000 M/sec                   [100.00%]
               4,595 CPU-migrations            #    0.000 M/sec                   [100.00%]
          63,133,119 page-faults               #    0.000 M/sec
  147,977,747,269,768 cycles                   #    1.066 GHz                     [100.00%]
  200,524,196,493,108 stalled-cycles-frontend  #  135.51% frontend cycles idle    [100.00%]
  105,175,163,716,388 stalled-cycles-backend   #   71.07% backend  cycles idle    [100.00%]
  180,916,213,503,160 instructions             #    1.22  insns per cycle
                                               #    1.11  stalled cycles per insn [100.00%]
  26,999,511,005,868 branches                  #  194.536 M/sec                   [100.00%]
         714,066,351 branch-misses             #    0.00% of all branches

       216.196778807 seconds time elapsed

As with previous versions of the patch, We're getting about a 2x
performance increase here.  Here's a link to the test case I used, along
with the little wrapper to activate the flag:

  http://oss.sgi.com/projects/memtests/thp_pthread_mmprctlv3.tar.gz

This patch (of 3):

Revert commit 8e72033f2a and add in code to fix up any issues caused
by the revert.

The revert is necessary because hugepage_madvise would return -EINVAL
when VM_NOHUGEPAGE is set, which will break subsequent chunks of this
patch set.

Here's a snip of an e-mail from Gerald detailing the original purpose of
this code, and providing justification for the revert:

  "The intent of commit 8e72033f2a was to guard against any future
   programming errors that may result in an madvice(MADV_HUGEPAGE) on
   guest mappings, which would crash the kernel.

   Martin suggested adding the bit to arch/s390/mm/pgtable.c, if
   8e72033f2a was to be reverted, because that check will also prevent
   a kernel crash in the case described above, it will now send a
   SIGSEGV instead.

   This would now also allow to do the madvise on other parts, if
   needed, so it is a more flexible approach.  One could also say that
   it would have been better to do it this way right from the
   beginning..."

Signed-off-by: Alex Thorlton <athorlton@sgi.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Johannes Weiner <hannes@cmpxchg.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>
2014-04-07 16:35:51 -07:00
Joonsoo Kim
b6c750163c mm/compaction: clean-up code on success of ballon isolation
It is just for clean-up to reduce code size and improve readability.
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: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:51 -07:00
Joonsoo Kim
c122b2087a mm/compaction: check pageblock suitability once per pageblock
isolation_suitable() and migrate_async_suitable() is used to be sure
that this pageblock range is fine to be migragted.  It isn't needed to
call it on every page.  Current code do well if not suitable, but, don't
do well when suitable.

1) It re-checks isolation_suitable() on each page of a pageblock that was
   already estabilished as suitable.
2) It re-checks migrate_async_suitable() on each page of a pageblock that
   was not entered through the next_pageblock: label, because
   last_pageblock_nr is not otherwise updated.

This patch fixes situation by 1) calling isolation_suitable() only once
per pageblock and 2) always updating last_pageblock_nr to the pageblock
that was just checked.

Additionally, move PageBuddy() check after pageblock unit check, since
pageblock check is the first thing we should do and makes things more
simple.

[vbabka@suse.cz: rephrase commit description]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
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>
2014-04-07 16:35:51 -07:00
Joonsoo Kim
be1aa03b97 mm/compaction: change the timing to check to drop the spinlock
It is odd to drop the spinlock when we scan (SWAP_CLUSTER_MAX - 1) th
pfn page.  This may results in below situation while isolating
migratepage.

1. try isolate 0x0 ~ 0x200 pfn pages.
2. When low_pfn is 0x1ff, ((low_pfn+1) % SWAP_CLUSTER_MAX) == 0, so drop
   the spinlock.
3. Then, to complete isolating, retry to aquire the lock.

I think that it is better to use SWAP_CLUSTER_MAX th pfn for checking the
criteria about dropping the lock.  This has no harm 0x0 pfn, because, at
this time, locked variable would be false.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
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>
2014-04-07 16:35:51 -07:00
Joonsoo Kim
01ead5340b mm/compaction: do not call suitable_migration_target() on every page
suitable_migration_target() checks that pageblock is suitable for
migration target.  In isolate_freepages_block(), it is called on every
page and this is inefficient.  So make it called once per pageblock.

suitable_migration_target() also checks if page is highorder or not, but
it's criteria for highorder is pageblock order.  So calling it once
within pageblock range has no problem.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
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>
2014-04-07 16:35:51 -07:00
Joonsoo Kim
7d348b9ea6 mm/compaction: disallow high-order page for migration target
Purpose of compaction is to get a high order page.  Currently, if we
find high-order page while searching migration target page, we break it
to order-0 pages and use them as migration target.  It is contrary to
purpose of compaction, so disallow high-order page to be used for
migration target.

Additionally, clean-up logic in suitable_migration_target() to simplify
the code.  There is no functional changes from this clean-up.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
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>
2014-04-07 16:35:51 -07:00
Michal Hocko
70ef57e6c2 mm: exclude memoryless nodes from zone_reclaim
We had a report about strange OOM killer strikes on a PPC machine
although there was a lot of swap free and a tons of anonymous memory
which could be swapped out.  In the end it turned out that the OOM was a
side effect of zone reclaim which wasn't unmapping and swapping out and
so the system was pushed to the OOM.  Although this sounds like a bug
somewhere in the kswapd vs.  zone reclaim vs.  direct reclaim
interaction numactl on the said hardware suggests that the zone reclaim
should not have been set in the first place:

  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
  node 0 size: 0 MB
  node 0 free: 0 MB
  node 2 cpus:
  node 2 size: 7168 MB
  node 2 free: 6019 MB
  node distances:
  node   0   2
  0:  10  40
  2:  40  10

So all the CPUs are associated with Node0 which doesn't have any memory
while Node2 contains all the available memory.  Node distances cause an
automatic zone_reclaim_mode enabling.

Zone reclaim is intended to keep the allocations local but this doesn't
make any sense on the memoryless nodes.  So let's exclude such nodes for
init_zone_allows_reclaim which evaluates zone reclaim behavior and
suitable reclaim_nodes.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Tested-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.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>
2014-04-07 16:35:50 -07:00
Davidlohr Bueso
7aa6b4ad5a mm/memory.c: update comment in unmap_single_vma()
The described issue now occurs inside mmap_region().  And unfortunately
is still valid.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:50 -07:00
Weijie Yang
9bbc04eeb0 mm/vmscan: do not check compaction_ready on promoted zones
We abort direct reclaim if we find the zone is ready for compaction.
Sometimes the zone is just a promoted highmem zone to force a scan of
highmem, which is not the intended zone the caller want to allocate a
page from.  In this situation, setting aborted_reclaim to indicate the
caller turned back to retry the allocation is waste of time and could
cause a loop in __alloc_pages_slowpath().

This patch does not check compaction_ready() on promoted zones to avoid
the above situation.  Only set aborted_reclaim if the caller intended
zone is ready for compaction.

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Rik van Riel <riel@redhat.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>
2014-04-07 16:35:50 -07:00
Weijie Yang
619d0d76c1 mm/vmscan: restore sc->gfp_mask after promoting it to __GFP_HIGHMEM
We promote sc->gfp_mask to __GFP_HIGHMEM to forcibly scan highmem if
there are too many buffer_heads pinning highmem.  See cc715d99e5 ("mm:
vmscan: forcibly scan highmem if there are too many buffer_heads pinning
highmem").

This patch restores sc->gfp_mask to its caller original value after
finishing the scan job, to avoid the impact on other invocations from
its upper caller, such as vmpressure_prio(), shrink_slab().

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Mel Gorman <mgorman@suse.de>
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>
2014-04-07 16:35:50 -07:00
Rik van Riel
a5338093bf mm: move mmu notifier call from change_protection to change_pmd_range
The NUMA scanning code can end up iterating over many gigabytes of
unpopulated memory, especially in the case of a freshly started KVM
guest with lots of memory.

This results in the mmu notifier code being called even when there are
no mapped pages in a virtual address range.  The amount of time wasted
can be enough to trigger soft lockup warnings with very large KVM
guests.

This patch moves the mmu notifier call to the pmd level, which
represents 1GB areas of memory on x86-64.  Furthermore, the mmu notifier
code is only called from the address in the PMD where present mappings
are first encountered.

The hugetlbfs code is left alone for now; hugetlb mappings are not
relocatable, and as such are left alone by the NUMA code, and should
never trigger this problem to begin with.

Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Xing Gang <gang.xing@hp.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:50 -07:00
Mel Gorman
1ad9f620c3 mm: numa: recheck for transhuge pages under lock during protection changes
Sasha reported the following bug using trinity

  kernel BUG at mm/mprotect.c:149!
  invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 20 PID: 26219 Comm: trinity-c216 Tainted: G        W    3.14.0-rc5-next-20140305-sasha-00011-ge06f5f3-dirty #105
  task: ffff8800b6c80000 ti: ffff880228436000 task.ti: ffff880228436000
  RIP: change_protection_range+0x3b3/0x500
  Call Trace:
    change_protection+0x25/0x30
    change_prot_numa+0x1b/0x30
    task_numa_work+0x279/0x360
    task_work_run+0xae/0xf0
    do_notify_resume+0x8e/0xe0
    retint_signal+0x4d/0x92

The VM_BUG_ON was added in -mm by the patch "mm,numa: reorganize
change_pmd_range".  The race existed without the patch but was just
harder to hit.

The problem is that a transhuge check is made without holding the PTL.
It's possible at the time of the check that a parallel fault clears the
pmd and inserts a new one which then triggers the VM_BUG_ON check.  This
patch removes the VM_BUG_ON but fixes the race by rechecking transhuge
under the PTL when marking page tables for NUMA hinting and bailing if a
race occurred.  It is not a problem for calls to mprotect() as they hold
mmap_sem for write.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reviewed-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>
2014-04-07 16:35:50 -07:00
Rik van Riel
88a9ab6e3d mm,numa: reorganize change_pmd_range()
Reorganize the order of ifs in change_pmd_range a little, in preparation
for the next patch.

[akpm@linux-foundation.org: fix indenting, per David]
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Xing Gang <gang.xing@hp.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:49 -07:00
Naoya Horiguchi
a9af0c5dfd mm/hugetlb.c: add NULL check of return value of huge_pte_offset
huge_pte_offset() could return NULL, so we need NULL check to avoid
potential NULL pointer dereferences.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:49 -07:00
Linus Torvalds
2d1eb87ae1 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM changes from Russell King:

 - Perf updates from Will Deacon:
   - Support for Qualcomm Krait processors (run perf on your phone!)
   - Support for Cortex-A12 (run perf stat on your FPGA!)
   - Support for perf_sample_event_took, allowing us to automatically decrease
     the sample rate if we can't handle the PMU interrupts quickly enough
     (run perf record on your FPGA!).

 - Basic uprobes support from David Long:
     This patch series adds basic uprobes support to ARM. It is based on
     patches developed earlier by Rabin Vincent. That approach of adding
     hooks into the kprobes instruction parsing code was not well received.
     This approach separates the ARM instruction parsing code in kprobes out
     into a separate set of functions which can be used by both kprobes and
     uprobes. Both kprobes and uprobes then provide their own semantic action
     tables to process the results of the parsing.

 - ARMv7M (microcontroller) updates from Uwe Kleine-König

 - OMAP DMA updates (recently added Vinod's Ack even though they've been
   sitting in linux-next for a few months) to reduce the reliance of
   omap-dma on the code in arch/arm.

 - SA11x0 changes from Dmitry Eremin-Solenikov and Alexander Shiyan

 - Support for Cortex-A12 CPU

 - Align support for ARMv6 with ARMv7 so they can cooperate better in a
   single zImage.

 - Addition of first AT_HWCAP2 feature bits for ARMv8 crypto support.

 - Removal of IRQ_DISABLED from various ARM files

 - Improved efficiency of virt_to_page() for single zImage

 - Patch from Ulf Hansson to permit runtime PM callbacks to be available for
   AMBA devices for suspend/resume as well.

 - Finally kill asm/system.h on ARM.

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (89 commits)
  dmaengine: omap-dma: more consolidation of CCR register setup
  dmaengine: omap-dma: move IRQ handling to omap-dma
  dmaengine: omap-dma: move register read/writes into omap-dma.c
  ARM: omap: dma: get rid of 'p' allocation and clean up
  ARM: omap: move dma channel allocation into plat-omap code
  ARM: omap: dma: get rid of errata global
  ARM: omap: clean up DMA register accesses
  ARM: omap: remove almost-const variables
  ARM: omap: remove references to disable_irq_lch
  dmaengine: omap-dma: cleanup errata 3.3 handling
  dmaengine: omap-dma: provide register read/write functions
  dmaengine: omap-dma: use cached CCR value when enabling DMA
  dmaengine: omap-dma: move barrier to omap_dma_start_desc()
  dmaengine: omap-dma: move clnk_ctrl setting to preparation functions
  dmaengine: omap-dma: improve efficiency loading C.SA/C.EI/C.FI registers
  dmaengine: omap-dma: consolidate clearing channel status register
  dmaengine: omap-dma: move CCR buffering disable errata out of the fast path
  dmaengine: omap-dma: provide register definitions
  dmaengine: omap-dma: consolidate setup of CCR
  dmaengine: omap-dma: consolidate setup of CSDP
  ...
2014-04-05 13:20:43 -07:00
Hugh Dickins
cda540ace6 mm: get_user_pages(write,force) refuse to COW in shared areas
get_user_pages(write=1, force=1) has always had odd behaviour on write-
protected shared mappings: although it demands FMODE_WRITE-access to the
underlying object (do_mmap_pgoff sets neither VM_SHARED nor VM_MAYWRITE
without that), it ends up with do_wp_page substituting private anonymous
Copied-On-Write pages for the shared file pages in the area.

That was long ago intentional, as a safety measure to prevent ptrace
setting a breakpoint (or POKETEXT or POKEDATA) from inadvertently
corrupting the underlying executable.  Yet exec and dynamic loaders open
the file read-only, and use MAP_PRIVATE rather than MAP_SHARED.

The traditional odd behaviour still causes surprises and bugs in mm, and
is probably not what any caller wants - even the comment on the flag
says "You do not want this" (although it's undoubtedly necessary for
overriding userspace protections in some contexts, and good when !write).

Let's stop doing that.  But it would be dangerous to remove the long-
standing safety at this stage, so just make get_user_pages(write,force)
fail with EFAULT when applied to a write-protected shared area.
Infiniband may in future want to force write through to underlying
object: we can add another FOLL_flag later to enable that if required.

Odd though the old behaviour was, there is no doubt that we may turn out
to break userspace with this change, and have to revert it quickly.
Issue a WARN_ON_ONCE to help debug the changed case (easily triggered by
userspace, so only once to prevent spamming the logs); and delay a few
associated cleanups until this change is proved.

get_user_pages callers who might see trouble from this change:
  ptrace poking, or writing to /proc/<pid>/mem
  drivers/infiniband/
  drivers/media/v4l2-core/
  drivers/gpu/drm/exynos/exynos_drm_gem.c
  drivers/staging/tidspbridge/core/tiomap3430.c
if they ever apply get_user_pages to write-protected shared mappings
of an object which was opened for writing.

I went to apply the same change to mm/nommu.c, but retreated.  NOMMU has
no place for COW, and its VM_flags conventions are not the same: I'd be
more likely to screw up NOMMU than make an improvement there.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 16:16:55 -07:00
Linus Torvalds
f7789dc0d4 Merge branch 'locks-3.15' of git://git.samba.org/jlayton/linux
Pull file locking updates from Jeff Layton:
 "Highlights:

   - maintainership change for fs/locks.c.  Willy's not interested in
     maintaining it these days, and is OK with Bruce and I taking it.
   - fix for open vs setlease race that Al ID'ed
   - cleanup and consolidation of file locking code
   - eliminate unneeded BUG() call
   - merge of file-private lock implementation"

* 'locks-3.15' of git://git.samba.org/jlayton/linux:
  locks: make locks_mandatory_area check for file-private locks
  locks: fix locks_mandatory_locked to respect file-private locks
  locks: require that flock->l_pid be set to 0 for file-private locks
  locks: add new fcntl cmd values for handling file private locks
  locks: skip deadlock detection on FL_FILE_PVT locks
  locks: pass the cmd value to fcntl_getlk/getlk64
  locks: report l_pid as -1 for FL_FILE_PVT locks
  locks: make /proc/locks show IS_FILE_PVT locks as type "FLPVT"
  locks: rename locks_remove_flock to locks_remove_file
  locks: consolidate checks for compatible filp->f_mode values in setlk handlers
  locks: fix posix lock range overflow handling
  locks: eliminate BUG() call when there's an unexpected lock on file close
  locks: add __acquires and __releases annotations to locks_start and locks_stop
  locks: remove "inline" qualifier from fl_link manipulation functions
  locks: clean up comment typo
  locks: close potential race between setlease and open
  MAINTAINERS: update entry for fs/locks.c
2014-04-04 14:21:20 -07:00
Russell King
bce5669be3 Merge branch 'devel-stable' into for-next 2014-04-04 00:33:49 +01:00
Linus Torvalds
76ca7d1cca Merge branch 'akpm' (incoming from Andrew)
Merge first patch-bomb from Andrew Morton:
 - Various misc bits
 - kmemleak fixes
 - small befs, codafs, cifs, efs, freexxfs, hfsplus, minixfs, reiserfs things
 - fanotify
 - I appear to have become SuperH maintainer
 - ocfs2 updates
 - direct-io tweaks
 - a bit of the MM queue
 - printk updates
 - MAINTAINERS maintenance
 - some backlight things
 - lib/ updates
 - checkpatch updates
 - the rtc queue
 - nilfs2 updates
 - Small Documentation/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (237 commits)
  Documentation/SubmittingPatches: remove references to patch-scripts
  Documentation/SubmittingPatches: update some dead URLs
  Documentation/filesystems/ntfs.txt: remove changelog reference
  Documentation/kmemleak.txt: updates
  fs/reiserfs/super.c: add __init to init_inodecache
  fs/reiserfs: move prototype declaration to header file
  fs/hfsplus/attributes.c: add __init to hfsplus_create_attr_tree_cache()
  fs/hfsplus/extents.c: fix concurrent acess of alloc_blocks
  fs/hfsplus/extents.c: remove unused variable in hfsplus_get_block
  nilfs2: update project's web site in nilfs2.txt
  nilfs2: update MAINTAINERS file entries fix
  nilfs2: verify metadata sizes read from disk
  nilfs2: add FITRIM ioctl support for nilfs2
  nilfs2: add nilfs_sufile_trim_fs to trim clean segs
  nilfs2: implementation of NILFS_IOCTL_SET_SUINFO ioctl
  nilfs2: add nilfs_sufile_set_suinfo to update segment usage
  nilfs2: add struct nilfs_suinfo_update and flags
  nilfs2: update MAINTAINERS file entries
  fs/coda/inode.c: add __init to init_inodecache()
  BEFS: logging cleanup
  ...
2014-04-03 16:22:16 -07:00
Raghavendra K T
6d2be915e5 mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages
Currently max_sane_readahead() returns zero on the cpu whose NUMA node
has no local memory which leads to readahead failure.  Fix this
readahead failure by returning minimum of (requested pages, 512).  Users
running applications on a memory-less cpu which needs readahead such as
streaming application see considerable boost in the performance.

Result:

fadvise experiment with FADV_WILLNEED on a PPC machine having memoryless
CPU with 1GB testfile (12 iterations) yielded around 46.66% improvement.

fadvise experiment with FADV_WILLNEED on a x240 machine with 1GB
testfile 32GB* 4G RAM numa machine (12 iterations) showed no impact on
the normal NUMA cases w/ patch.

  Kernel       Avg  Stddev
  base      7.4975   3.92%
  patched   7.4174   3.26%

[Andrew: making return value PAGE_SIZE independent]
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.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>
2014-04-03 16:21:05 -07:00
Vladimir Davydov
421af243b1 slub: do not drop slab_mutex for sysfs_slab_add
We release the slab_mutex while calling sysfs_slab_add from
__kmem_cache_create since commit 66c4c35c6b ("slub: Do not hold
slub_lock when calling sysfs_slab_add()"), because kobject_uevent called
by sysfs_slab_add might block waiting for the usermode helper to exec,
which would result in a deadlock if we took the slab_mutex while
executing it.

However, apart from complicating synchronization rules, releasing the
slab_mutex on kmem cache creation can result in a kmemcg-related race.
The point is that we check if the memcg cache exists before going to
__kmem_cache_create, but register the new cache in memcg subsys after
it.  Since we can drop the mutex there, several threads can see that the
memcg cache does not exist and proceed to creating it, which is wrong.

Fortunately, recently kobject_uevent was patched to call the usermode
helper with the UMH_NO_WAIT flag, making the deadlock impossible.
Therefore there is no point in releasing the slab_mutex while calling
sysfs_slab_add, so let's simplify kmem_cache_create synchronization and
fix the kmemcg-race mentioned above by holding the slab_mutex during the
whole cache creation path.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Greg KH <greg@kroah.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:05 -07:00
Dave Hansen
5509a5d27b drop_caches: add some documentation and info message
There is plenty of anecdotal evidence and a load of blog posts
suggesting that using "drop_caches" periodically keeps your system
running in "tip top shape".  Perhaps adding some kernel documentation
will increase the amount of accurate data on its use.

If we are not shrinking caches effectively, then we have real bugs.
Using drop_caches will simply mask the bugs and make them harder to
find, but certainly does not fix them, nor is it an appropriate
"workaround" to limit the size of the caches.  On the contrary, there
have been bug reports on issues that turned out to be misguided use of
cache dropping.

Dropping caches is a very drastic and disruptive operation that is good
for debugging and running tests, but if it creates bug reports from
production use, kernel developers should be aware of its use.

Add a bit more documentation about it, a syslog message to track down
abusers, and vmstat drop counters to help analyze problem reports.

[akpm@linux-foundation.org: checkpatch fixes]
[hannes@cmpxchg.org: add runtime suppression control]
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:04 -07:00
Sasha Levin
67f9fd91f9 mm: remove read_cache_page_async()
This patch removes read_cache_page_async() which wasn't really needed
anywhere and simplifies the code around it a bit.

read_cache_page_async() is useful when we want to read a page into the
cache without waiting for it to complete.  This happens when the
appropriate callback 'filler' doesn't complete its read operation and
releases the page lock immediately, and instead queues a different
completion routine to do that.  This never actually happened anywhere in
the code.

read_cache_page_async() had 3 different callers:

- read_cache_page() which is the sync version, it would just wait for
  the requested read to complete using wait_on_page_read().

- JFFS2 would call it from jffs2_gc_fetch_page(), but the filler
  function it supplied doesn't do any async reads, and would complete
  before the filler function returns - making it actually a sync read.

- CRAMFS would call it using the read_mapping_page_async() wrapper, with
  a similar story to JFFS2 - the filler function doesn't do anything that
  reminds async reads and would always complete before the filler function
  returns.

To sum it up, the code in mm/filemap.c never took advantage of having
read_cache_page_async().  While there are filler callbacks that do async
reads (such as the block one), we always called it with the
read_cache_page().

This patch adds a mandatory wait for read to complete when adding a new
page to the cache, and removes read_cache_page_async() and its wrappers.

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>
2014-04-03 16:21:04 -07:00
Kirill A. Shutemov
e9b71ca91a mm, thp: drop do_huge_pmd_wp_zero_page_fallback()
I've realized that there's no need for do_huge_pmd_wp_zero_page_fallback().
We can just split zero page with split_huge_page_pmd() and return
VM_FAULT_FALLBACK.  handle_pte_fault() will handle write-protection
fault for us.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:04 -07:00
Kirill A. Shutemov
3bb9779469 mm: consolidate code to setup pte
Extract and consolidate code to setup pte from do_read_fault(),
do_cow_fault() and do_shared_fault().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:04 -07:00
Kirill A. Shutemov
fb09a46425 mm: consolidate code to call vm_ops->page_mkwrite()
There are two functions which need to call vm_ops->page_mkwrite():
do_shared_fault() and do_wp_page().  We can consolidate preparation
code.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:04 -07:00
Kirill A. Shutemov
f0c6d4d295 mm: introduce do_shared_fault() and drop do_fault()
Introduce do_shared_fault().  The function does what do_fault() does for
write faults to shared mappings

Unlike do_fault(), do_shared_fault() is relatively clean and
straight-forward.

Old do_fault() is not needed anymore.  Let it die.

[lliubbo@gmail.com: fix NULL pointer dereference]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:03 -07:00
Kirill A. Shutemov
ec47c3b954 mm: introduce do_cow_fault()
Introduce do_cow_fault().  The function does what do_fault() does for
write page faults to private mappings.

Unlike do_fault(), do_read_fault() is relatively clean and
straight-forward.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:03 -07:00
Kirill A. Shutemov
e655fb2907 mm: introduce do_read_fault()
Introduce do_read_fault().  The function does what do_fault() does for
read page faults.

Unlike do_fault(), do_read_fault() is pretty clean and straightforward.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:03 -07:00
Kirill A. Shutemov
7eae74af32 mm: do_fault(): extract to call vm_ops->do_fault() to separate function
Extract code to vm_ops->do_fault() and basic error handling to separate
function.  The code will be reused.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:03 -07:00
Kirill A. Shutemov
80d7ef6614 mm: rename __do_fault() -> do_fault()
Current __do_fault() is awful and unmaintainable.  These patches try to
sort it out by split __do_fault() into three destinct codepaths:

 - to handle read page fault;
 - to handle write page fault to private mappings;
 - to handle write page fault to shared mappings;

I also found page refcount leak in PageHWPoison() path of __do_fault().

This patch (of 7):

do_fault() is unused: no reason for underscores.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:03 -07:00
Rashika Kheria
de49850725 mm/nobootmem.c: mark function as static
Mark function as static in nobootmem.c because it is not used outside
this file.

This eliminates the following warning in mm/nobootmem.c:

  mm/nobootmem.c:324:15: warning: no previous prototype for `___alloc_bootmem_node' [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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>
2014-04-03 16:21:02 -07:00
Rashika Kheria
d20199e1f5 mm/page_cgroup.c: mark functions as static
Mark functions as static in page_cgroup.c because they are not used
outside this file.

This eliminates the following warning in mm/page_cgroup.c:

  mm/page_cgroup.c:177:6: warning: no previous prototype for `__free_page_cgroup' [-Wmissing-prototypes]
  mm/page_cgroup.c:190:15: warning: no previous prototype for `online_page_cgroup' [-Wmissing-prototypes]
  mm/page_cgroup.c:225:15: warning: no previous prototype for `offline_page_cgroup' [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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>
2014-04-03 16:21:02 -07:00
Rashika Kheria
2eb2e141c0 mm/process_vm_access.c: mark function as static
Mark function as static in process_vm_access.c because it is not used
outside this file.

This eliminates the following warning in mm/process_vm_access.c:

  mm/process_vm_access.c:416:1: warning: no previous prototype for `compat_process_vm_rw' [-Wmissing-prototypes]

[akpm@linux-foundation.org: remove unneeded asmlinkage - compat_process_vm_rw isn't referenced from asm]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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>
2014-04-03 16:21:02 -07:00
Rashika Kheria
eafd4dc4d7 mm/mmap.c: mark function as static
Mark function as static in mmap.c because they are not used outside this
file.

This eliminates the following warning in mm/mmap.c:

  mm/mmap.c:407:6: warning: no previous prototype for `validate_mm' [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: 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>
2014-04-03 16:21:02 -07:00
Rashika Kheria
b19a99392a mm/memory.c: mark functions as static
mark functions as static in memory.c because they are not used outside
this file.

This eliminates the following warnings in mm/memory.c:

  mm/memory.c:3530:5: warning: no previous prototype for `numa_migrate_prep' [-Wmissing-prototypes]
  mm/memory.c:3545:5: warning: no previous prototype for `do_numa_page' [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: 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>
2014-04-03 16:21:02 -07:00
Rashika Kheria
74e77fb9a2 mm/compaction.c: mark function as static
Mark function as static in compaction.c because it is not used outside
this file.

This eliminates the following warning from mm/compaction.c:

  mm/compaction.c:1190:9: warning: no previous prototype for `sysfs_compact_node' [-Wmissing-prototypes

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: 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>
2014-04-03 16:21:02 -07:00
David Rientjes
119d6d59dc mm, compaction: avoid isolating pinned pages
Page migration will fail for memory that is pinned in memory with, for
example, get_user_pages().  In this case, it is unnecessary to take
zone->lru_lock or isolating the page and passing it to page migration
which will ultimately fail.

This is a racy check, the page can still change from under us, but in
that case we'll just fail later when attempting to move the page.

This avoids very expensive memory compaction when faulting transparent
hugepages after pinning a lot of memory with a Mellanox driver.

On a 128GB machine and pinning ~120GB of memory, before this patch we
see the enormous disparity in the number of page migration failures
because of the pinning (from /proc/vmstat):

	compact_pages_moved 8450
	compact_pagemigrate_failed 15614415

0.05% of pages isolated are successfully migrated and explicitly
triggering memory compaction takes 102 seconds.  After the patch:

	compact_pages_moved 9197
	compact_pagemigrate_failed 7

99.9% of pages isolated are now successfully migrated in this
configuration and memory compaction takes less than one second.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
David Rientjes
f412c97abe mm, hugetlb: mark some bootstrap functions as __init
Both prep_compound_huge_page() and prep_compound_gigantic_page() are
only called at bootstrap and can be marked as __init.

The __SetPageTail(page) in prep_compound_gigantic_page() happening
before page->first_page is initialized is not concerning since this is
bootstrap.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
Johannes Weiner
449dd6984d mm: keep page cache radix tree nodes in check
Previously, page cache radix tree nodes were freed after reclaim emptied
out their page pointers.  But now reclaim stores shadow entries in their
place, which are only reclaimed when the inodes themselves are
reclaimed.  This is problematic for bigger files that are still in use
after they have a significant amount of their cache reclaimed, without
any of those pages actually refaulting.  The shadow entries will just
sit there and waste memory.  In the worst case, the shadow entries will
accumulate until the machine runs out of memory.

To get this under control, the VM will track radix tree nodes
exclusively containing shadow entries on a per-NUMA node list.  Per-NUMA
rather than global because we expect the radix tree nodes themselves to
be allocated node-locally and we want to reduce cross-node references of
otherwise independent cache workloads.  A simple shrinker will then
reclaim these nodes on memory pressure.

A few things need to be stored in the radix tree node to implement the
shadow node LRU and allow tree deletions coming from the list:

1. There is no index available that would describe the reverse path
   from the node up to the tree root, which is needed to perform a
   deletion.  To solve this, encode in each node its offset inside the
   parent.  This can be stored in the unused upper bits of the same
   member that stores the node's height at no extra space cost.

2. The number of shadow entries needs to be counted in addition to the
   regular entries, to quickly detect when the node is ready to go to
   the shadow node LRU list.  The current entry count is an unsigned
   int but the maximum number of entries is 64, so a shadow counter
   can easily be stored in the unused upper bits.

3. Tree modification needs tree lock and tree root, which are located
   in the address space, so store an address_space backpointer in the
   node.  The parent pointer of the node is in a union with the 2-word
   rcu_head, so the backpointer comes at no extra cost as well.

4. The node needs to be linked to an LRU list, which requires a list
   head inside the node.  This does increase the size of the node, but
   it does not change the number of objects that fit into a slab page.

[akpm@linux-foundation.org: export the right function]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
Johannes Weiner
a528910e12 mm: thrash detection-based file cache sizing
The VM maintains cached filesystem pages on two types of lists.  One
list holds the pages recently faulted into the cache, the other list
holds pages that have been referenced repeatedly on that first list.
The idea is to prefer reclaiming young pages over those that have shown
to benefit from caching in the past.  We call the recently usedbut
ultimately was not significantly better than a FIFO policy and still
thrashed cache based on eviction speed, rather than actual demand for
cache.

This patch solves one half of the problem by decoupling the ability to
detect working set changes from the inactive list size.  By maintaining
a history of recently evicted file pages it can detect frequently used
pages with an arbitrarily small inactive list size, and subsequently
apply pressure on the active list based on actual demand for cache, not
just overall eviction speed.

Every zone maintains a counter that tracks inactive list aging speed.
When a page is evicted, a snapshot of this counter is stored in the
now-empty page cache radix tree slot.  On refault, the minimum access
distance of the page can be assessed, to evaluate whether the page
should be part of the active list or not.

This fixes the VM's blindness towards working set changes in excess of
the inactive list.  And it's the foundation to further improve the
protection ability and reduce the minimum inactive list size of 50%.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
Johannes Weiner
91b0abe36a mm + fs: store shadow entries in page cache
Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page.  As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently.  At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.

Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate.  Reclaim will check
for this flag before installing shadow pages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
Johannes Weiner
0cd6144aad mm + fs: prepare for non-page entries in page cache radix trees
shmem mappings already contain exceptional entries where swap slot
information is remembered.

To be able to store eviction information for regular page cache, prepare
every site dealing with the radix trees directly to handle entries other
than pages.

The common lookup functions will filter out non-page entries and return
NULL for page cache holes, just as before.  But provide a raw version of
the API which returns non-page entries as well, and switch shmem over to
use it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:00 -07:00
Johannes Weiner
e7b563bb2a mm: filemap: move radix tree hole searching here
The radix tree hole searching code is only used for page cache, for
example the readahead code trying to get a a picture of the area
surrounding a fault.

It sufficed to rely on the radix tree definition of holes, which is
"empty tree slot".  But this is about to change, though, as shadow page
descriptors will be stored in the page cache after the actual pages get
evicted from memory.

Move the functions over to mm/filemap.c and make them native page cache
operations, where they can later be adapted to handle the new definition
of "page cache hole".

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:00 -07:00
Johannes Weiner
6dbaf22ce1 mm: shmem: save one radix tree lookup when truncating swapped pages
Page cache radix tree slots are usually stabilized by the page lock, but
shmem's swap cookies have no such thing.  Because the overall truncation
loop is lockless, the swap entry is currently confirmed by a tree lookup
and then deleted by another tree lookup under the same tree lock region.

Use radix_tree_delete_item() instead, which does the verification and
deletion with only one lookup.  This also allows removing the
delete-only special case from shmem_radix_tree_replace().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:00 -07:00