1. 31 Jul, 2012 40 commits
    • Mel Gorman's avatar
      net: introduce sk_gfp_atomic() to allow addition of GFP flags depending on the individual socket · 99a1dec7
      Mel Gorman authored
      Introduce sk_gfp_atomic(), this function allows to inject sock specific
      flags to each sock related allocation.  It is only used on allocation
      paths that may be required for writing pages back to network storage.
      
      [davem@davemloft.net: Use sk_gfp_atomic only when necessary]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      99a1dec7
    • Mel Gorman's avatar
      mm: ignore mempolicies when using ALLOC_NO_WATERMARK · 183f6371
      Mel Gorman authored
      The reserve is proportionally distributed over all !highmem zones in the
      system.  So we need to allow an emergency allocation access to all zones.
      In order to do that we need to break out of any mempolicy boundaries we
      might have.
      
      In my opinion that does not break mempolicies as those are user oriented
      and not system oriented.  That is, system allocations are not guaranteed
      to be within mempolicy boundaries.  For instance IRQs do not even have a
      mempolicy.
      
      So breaking out of mempolicy boundaries for 'rare' emergency allocations,
      which are always system allocations (as opposed to user) is ok.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      183f6371
    • Mel Gorman's avatar
      mm: only set page->pfmemalloc when ALLOC_NO_WATERMARKS was used · cfd19c5a
      Mel Gorman authored
      __alloc_pages_slowpath() is called when the number of free pages is below
      the low watermark.  If the caller is entitled to use ALLOC_NO_WATERMARKS
      then the page will be marked page->pfmemalloc.  This protects more pages
      than are strictly necessary as we only need to protect pages allocated
      below the min watermark (the pfmemalloc reserves).
      
      This patch only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was
      required to allocate the page.
      
      [rientjes@google.com: David noticed the problem during review]
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cfd19c5a
    • Mel Gorman's avatar
      mm: allow PF_MEMALLOC from softirq context · 907aed48
      Mel Gorman authored
      This is needed to allow network softirq packet processing to make use of
      PF_MEMALLOC.
      
      Currently softirq context cannot use PF_MEMALLOC due to it not being
      associated with a task, and therefore not having task flags to fiddle with
      - thus the gfp to alloc flag mapping ignores the task flags when in
      interrupts (hard or soft) context.
      
      Allowing softirqs to make use of PF_MEMALLOC therefore requires some
      trickery.  This patch borrows the task flags from whatever process happens
      to be preempted by the softirq.  It then modifies the gfp to alloc flags
      mapping to not exclude task flags in softirq context, and modify the
      softirq code to save, clear and restore the PF_MEMALLOC flag.
      
      The save and clear, ensures the preempted task's PF_MEMALLOC flag doesn't
      leak into the softirq.  The restore ensures a softirq's PF_MEMALLOC flag
      cannot leak back into the preempted process.  This should be safe due to
      the following reasons
      
      Softirqs can run on multiple CPUs sure but the same task should not be
      	executing the same softirq code. Neither should the softirq
      	handler be preempted by any other softirq handler so the flags
      	should not leak to an unrelated softirq.
      
      Softirqs re-enable hardware interrupts in __do_softirq() so can be
      	preempted by hardware interrupts so PF_MEMALLOC is inherited
      	by the hard IRQ. However, this is similar to a process in
      	reclaim being preempted by a hardirq. While PF_MEMALLOC is
      	set, gfp_to_alloc_flags() distinguishes between hard and
      	soft irqs and avoids giving a hardirq the ALLOC_NO_WATERMARKS
      	flag.
      
      If the softirq is deferred to ksoftirq then its flags may be used
              instead of a normal tasks but as the softirq cannot be preempted,
              the PF_MEMALLOC flag does not leak to other code by accident.
      
      [davem@davemloft.net: Document why PF_MEMALLOC is safe]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      907aed48
    • Mel Gorman's avatar
      mm: introduce __GFP_MEMALLOC to allow access to emergency reserves · b37f1dd0
      Mel Gorman authored
      __GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
      like PF_MEMALLOC.  It allows one to pass along the memalloc state in
      object related allocation flags as opposed to task related flags, such as
      sk->sk_allocation.  This removes the need for ALLOC_PFMEMALLOC as callers
      using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
      enough to identify allocations related to page reclaim.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b37f1dd0
    • Christoph Lameter's avatar
      mm: slub: optimise the SLUB fast path to avoid pfmemalloc checks · 5091b74a
      Christoph Lameter authored
      This patch removes the check for pfmemalloc from the alloc hotpath and
      puts the logic after the election of a new per cpu slab.  For a pfmemalloc
      page we do not use the fast path but force the use of the slow path which
      is also used for the debug case.
      
      This has the side-effect of weakening pfmemalloc processing in the
      following way;
      
      1. A process that is allocating for network swap calls __slab_alloc.
         pfmemalloc_match is true so the freelist is loaded and c->freelist is
         now pointing to a pfmemalloc page.
      
      2. A process that is attempting normal allocations calls slab_alloc,
         finds the pfmemalloc page on the freelist and uses it because it did
         not check pfmemalloc_match()
      
      The patch allows non-pfmemalloc allocations to use pfmemalloc pages with
      the kmalloc slabs being the most vunerable caches on the grounds they
      are most likely to have a mix of pfmemalloc and !pfmemalloc requests. A
      later patch will still protect the system as processes will get throttled
      if the pfmemalloc reserves get depleted but performance will not degrade
      as smoothly.
      
      [mgorman@suse.de: Expanded changelog]
      Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5091b74a
    • Mel Gorman's avatar
      mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages · 072bb0aa
      Mel Gorman authored
      When a user or administrator requires swap for their application, they
      create a swap partition and file, format it with mkswap and activate it
      with swapon.  Swap over the network is considered as an option in diskless
      systems.  The two likely scenarios are when blade servers are used as part
      of a cluster where the form factor or maintenance costs do not allow the
      use of disks and thin clients.
      
      The Linux Terminal Server Project recommends the use of the Network Block
      Device (NBD) for swap according to the manual at
      https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download
      There is also documentation and tutorials on how to setup swap over NBD at
      places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The
      nbd-client also documents the use of NBD as swap.  Despite this, the fact
      is that a machine using NBD for swap can deadlock within minutes if swap
      is used intensively.  This patch series addresses the problem.
      
      The core issue is that network block devices do not use mempools like
      normal block devices do.  As the host cannot control where they receive
      packets from, they cannot reliably work out in advance how much memory
      they might need.  Some years ago, Peter Zijlstra developed a series of
      patches that supported swap over an NFS that at least one distribution is
      carrying within their kernels.  This patch series borrows very heavily
      from Peter's work to support swapping over NBD as a pre-requisite to
      supporting swap-over-NFS.  The bulk of the complexity is concerned with
      preserving memory that is allocated from the PFMEMALLOC reserves for use
      by the network layer which is needed for both NBD and NFS.
      
      Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to
      	preserve access to pages allocated under low memory situations
      	to callers that are freeing memory.
      
      Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks
      
      Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC
      	reserves without setting PFMEMALLOC.
      
      Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves
      	for later use by network packet processing.
      
      Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required
      
      Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set.
      
      Patches 7-12 allows network processing to use PFMEMALLOC reserves when
      	the socket has been marked as being used by the VM to clean pages. If
      	packets are received and stored in pages that were allocated under
      	low-memory situations and are unrelated to the VM, the packets
      	are dropped.
      
      	Patch 11 reintroduces __skb_alloc_page which the networking
      	folk may object to but is needed in some cases to propogate
      	pfmemalloc from a newly allocated page to an skb. If there is a
      	strong objection, this patch can be dropped with the impact being
      	that swap-over-network will be slower in some cases but it should
      	not fail.
      
      Patch 13 is a micro-optimisation to avoid a function call in the
      	common case.
      
      Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use
      	PFMEMALLOC if necessary.
      
      Patch 15 notes that it is still possible for the PFMEMALLOC reserve
      	to be depleted. To prevent this, direct reclaimers get throttled on
      	a waitqueue if 50% of the PFMEMALLOC reserves are depleted.  It is
      	expected that kswapd and the direct reclaimers already running
      	will clean enough pages for the low watermark to be reached and
      	the throttled processes are woken up.
      
      Patch 16 adds a statistic to track how often processes get throttled
      
      Some basic performance testing was run using kernel builds, netperf on
      loopback for UDP and TCP, hackbench (pipes and sockets), iozone and
      sysbench.  Each of them were expected to use the sl*b allocators
      reasonably heavily but there did not appear to be significant performance
      variances.
      
      For testing swap-over-NBD, a machine was booted with 2G of RAM with a
      swapfile backed by NBD.  8*NUM_CPU processes were started that create
      anonymous memory mappings and read them linearly in a loop.  The total
      size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
      memory pressure.
      
      Without the patches and using SLUB, the machine locks up within minutes
      and runs to completion with them applied.  With SLAB, the story is
      different as an unpatched kernel run to completion.  However, the patched
      kernel completed the test 45% faster.
      
      MICRO
                                               3.5.0-rc2 3.5.0-rc2
      					 vanilla     swapnbd
      Unrecognised test vmscan-anon-mmap-write
      MMTests Statistics: duration
      Sys Time Running Test (seconds)             197.80    173.07
      User+Sys Time Running Test (seconds)        206.96    182.03
      Total Elapsed Time (seconds)               3240.70   1762.09
      
      This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages
      
      Allocations of pages below the min watermark run a risk of the machine
      hanging due to a lack of memory.  To prevent this, only callers who have
      PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are
      allowed to allocate with ALLOC_NO_WATERMARKS.  Once they are allocated to
      a slab though, nothing prevents other callers consuming free objects
      within those slabs.  This patch limits access to slab pages that were
      alloced from the PFMEMALLOC reserves.
      
      When this patch is applied, pages allocated from below the low watermark
      are returned with page->pfmemalloc set and it is up to the caller to
      determine how the page should be protected.  SLAB restricts access to any
      page with page->pfmemalloc set to callers which are known to able to
      access the PFMEMALLOC reserve.  If one is not available, an attempt is
      made to allocate a new page rather than use a reserve.  SLUB is a bit more
      relaxed in that it only records if the current per-CPU page was allocated
      from PFMEMALLOC reserve and uses another partial slab if the caller does
      not have the necessary GFP or process flags.  This was found to be
      sufficient in tests to avoid hangs due to SLUB generally maintaining
      smaller lists than SLAB.
      
      In low-memory conditions it does mean that !PFMEMALLOC allocators can fail
      a slab allocation even though free objects are available because they are
      being preserved for callers that are freeing pages.
      
      [a.p.zijlstra@chello.nl: Original implementation]
      [sebastian@breakpoint.cc: Correct order of page flag clearing]
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: David Miller <davem@davemloft.net>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Christoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      072bb0aa
    • Minchan Kim's avatar
      memory-hotplug: fix kswapd looping forever problem · 702d1a6e
      Minchan Kim authored
      When hotplug offlining happens on zone A, it starts to mark freed page as
      MIGRATE_ISOLATE type in buddy for preventing further allocation.
      (MIGRATE_ISOLATE is very irony type because it's apparently on buddy but
      we can't allocate them).
      
      When the memory shortage happens during hotplug offlining, current task
      starts to reclaim, then wake up kswapd.  Kswapd checks watermark, then go
      sleep because current zone_watermark_ok_safe doesn't consider
      MIGRATE_ISOLATE freed page count.  Current task continue to reclaim in
      direct reclaim path without kswapd's helping.  The problem is that
      zone->all_unreclaimable is set by only kswapd so that current task would
      be looping forever like below.
      
      __alloc_pages_slowpath
      restart:
      	wake_all_kswapd
      rebalance:
      	__alloc_pages_direct_reclaim
      		do_try_to_free_pages
      			if global_reclaim && !all_unreclaimable
      				return 1; /* It means we did did_some_progress */
      	skip __alloc_pages_may_oom
      	should_alloc_retry
      		goto rebalance;
      
      If we apply KOSAKI's patch[1] which doesn't depends on kswapd about
      setting zone->all_unreclaimable, we can solve this problem by killing some
      task in direct reclaim path.  But it doesn't wake up kswapd, still.  It
      could be a problem still if other subsystem needs GFP_ATOMIC request.  So
      kswapd should consider MIGRATE_ISOLATE when it calculate free pages BEFORE
      going sleep.
      
      This patch counts the number of MIGRATE_ISOLATE page block and
      zone_watermark_ok_safe will consider it if the system has such blocks
      (fortunately, it's very rare so no problem in POV overhead and kswapd is
      never hotpath).
      
      Copy/modify from Mel's quote
      "
      Ideal solution would be "allocating" the pageblock.
      It would keep the free space accounting as it is but historically,
      memory hotplug didn't allocate pages because it would be difficult to
      detect if a pageblock was isolated or if part of some balloon.
      Allocating just full pageblocks would work around this, However,
      it would play very badly with CMA.
      "
      
      [1] http://lkml.org/lkml/2012/6/14/74
      
      [akpm@linux-foundation.org: simplify nr_zone_isolate_freepages(), rework zone_watermark_ok_safe() comment, simplify set_pageblock_isolate() and restore_pageblock_isolate()]
      [akpm@linux-foundation.org: fix CONFIG_MEMORY_ISOLATION=n build]
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Suggested-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Tested-by: default avatarAaditya Kumar <aaditya.kumar.30@gmail.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      702d1a6e
    • Minchan Kim's avatar
      mm: fix free page check in zone_watermark_ok() · 2cfed075
      Minchan Kim authored
      __zone_watermark_ok currently compares free_pages which is a signed type
      with z->lowmem_reserve[classzone_idx] which is unsigned which might lead
      to sign overflow if free_pages doesn't satisfy the given order (or it came
      as negative already) and then we rely on the following order loop to fix
      it (which doesn't work for order-0).  Let's fix the type conversion and do
      not rely on the given value of free_pages or follow up fixups.
      
      This patch fixes it because "memory-hotplug: fix kswapd looping forever
      problem" depends on this.
      
      As benefit of this patch, it doesn't rely on the loop to exit
      __zone_watermark_ok in case of high order check and make the first test
      effective.(ie, if (free_pages <= min + lowmem_reserve))
      
      Aaditya reported this problem when he test my hotplug patch.
      Reported-off-by: default avatarAaditya Kumar <aaditya.kumar@ap.sony.com>
      Tested-by: default avatarAaditya Kumar <aaditya.kumar@ap.sony.com>
      Signed-off-by: default avatarAaditya Kumar <aaditya.kumar@ap.sony.com>
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2cfed075
    • Minchan Kim's avatar
      mm: factor out memory isolate functions · ee6f509c
      Minchan Kim authored
      mm/page_alloc.c has some memory isolation functions but they are used only
      when we enable CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}.  So let's make
      it configurable by new CONFIG_MEMORY_ISOLATION so that it can reduce
      binary size and we can check it simple by CONFIG_MEMORY_ISOLATION, not if
      defined CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ee6f509c
    • David Rientjes's avatar
      mm, memcg: move all oom handling to memcontrol.c · 876aafbf
      David Rientjes authored
      By globally defining check_panic_on_oom(), the memcg oom handler can be
      moved entirely to mm/memcontrol.c.  This removes the ugly #ifdef in the
      oom killer and cleans up the code.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      876aafbf
    • David Rientjes's avatar
      mm, oom: reduce dependency on tasklist_lock · 6b0c81b3
      David Rientjes authored
      Since exiting tasks require write_lock_irq(&tasklist_lock) several times,
      try to reduce the amount of time the readside is held for oom kills.  This
      makes the interface with the memcg oom handler more consistent since it
      now never needs to take tasklist_lock unnecessarily.
      
      The only time the oom killer now takes tasklist_lock is when iterating the
      children of the selected task, everything else is protected by
      rcu_read_lock().
      
      This requires that a reference to the selected process, p, is grabbed
      before calling oom_kill_process().  It may release it and grab a reference
      on another one of p's threads if !p->mm, but it also guarantees that it
      will release the reference before returning.
      
      [hughd@google.com: fix duplicate put_task_struct()]
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6b0c81b3
    • David Rientjes's avatar
      mm, memcg: introduce own oom handler to iterate only over its own threads · 9cbb78bb
      David Rientjes authored
      The global oom killer is serialized by the per-zonelist
      try_set_zonelist_oom() which is used in the page allocator.  Concurrent
      oom kills are thus a rare event and only occur in systems using
      mempolicies and with a large number of nodes.
      
      Memory controller oom kills, however, can frequently be concurrent since
      there is no serialization once the oom killer is called for oom conditions
      in several different memcgs in parallel.
      
      This creates a massive contention on tasklist_lock since the oom killer
      requires the readside for the tasklist iteration.  If several memcgs are
      calling the oom killer, this lock can be held for a substantial amount of
      time, especially if threads continue to enter it as other threads are
      exiting.
      
      Since the exit path grabs the writeside of the lock with irqs disabled in
      a few different places, this can cause a soft lockup on cpus as a result
      of tasklist_lock starvation.
      
      The kernel lacks unfair writelocks, and successful calls to the oom killer
      usually result in at least one thread entering the exit path, so an
      alternative solution is needed.
      
      This patch introduces a seperate oom handler for memcgs so that they do
      not require tasklist_lock for as much time.  Instead, it iterates only
      over the threads attached to the oom memcg and grabs a reference to the
      selected thread before calling oom_kill_process() to ensure it doesn't
      prematurely exit.
      
      This still requires tasklist_lock for the tasklist dump, iterating
      children of the selected process, and killing all other threads on the
      system sharing the same memory as the selected victim.  So while this
      isn't a complete solution to tasklist_lock starvation, it significantly
      reduces the amount of time that it is held.
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarSha Zhengju <handai.szj@taobao.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9cbb78bb
    • David Rientjes's avatar
      mm, oom: introduce helper function to process threads during scan · 462607ec
      David Rientjes authored
      This patch introduces a helper function to process each thread during the
      iteration over the tasklist.  A new return type, enum oom_scan_t, is
      defined to determine the future behavior of the iteration:
      
       - OOM_SCAN_OK: continue scanning the thread and find its badness,
      
       - OOM_SCAN_CONTINUE: do not consider this thread for oom kill, it's
         ineligible,
      
       - OOM_SCAN_ABORT: abort the iteration and return, or
      
       - OOM_SCAN_SELECT: always select this thread with the highest badness
         possible.
      
      There is no functional change with this patch.  This new helper function
      will be used in the next patch in the memory controller.
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Reviewed-by: default avatarSha Zhengju <handai.szj@taobao.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      462607ec
    • David Rientjes's avatar
      mm, oom: move declaration for mem_cgroup_out_of_memory to oom.h · 62ce1c70
      David Rientjes authored
      mem_cgroup_out_of_memory() is defined in mm/oom_kill.c, so declare it in
      linux/oom.h rather than linux/memcontrol.h.
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      62ce1c70
    • Jiang Liu's avatar
      mm/hotplug: mark memory hotplug code in page_alloc.c as __meminit · 4ed7e022
      Jiang Liu authored
      Mark functions used by both boot and memory hotplug as __meminit to reduce
      memory footprint when memory hotplug is disabled.
      
      Alos guard zone_pcp_update() with CONFIG_MEMORY_HOTPLUG because it's only
      used by memory hotplug code.
      Signed-off-by: default avatarJiang Liu <liuj97@gmail.com>
      Cc: Wei Wang <Bessel.Wang@huawei.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Keping Chen <chenkeping@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4ed7e022
    • Jiang Liu's avatar
      mm/hotplug: free zone->pageset when a zone becomes empty · 340175b7
      Jiang Liu authored
      When a zone becomes empty after memory offlining, free zone->pageset.
      Otherwise it will cause memory leak when adding memory to the empty zone
      again because build_all_zonelists() will allocate zone->pageset for an
      empty zone.
      Signed-off-by: default avatarJiang Liu <liuj97@gmail.com>
      Signed-off-by: default avatarWei Wang <Bessel.Wang@huawei.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Keping Chen <chenkeping@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      340175b7
    • Jiang Liu's avatar
      mm/hotplug: correctly add new zone to all other nodes' zone lists · 08dff7b7
      Jiang Liu authored
      When online_pages() is called to add new memory to an empty zone, it
      rebuilds all zone lists by calling build_all_zonelists().  But there's a
      bug which prevents the new zone to be added to other nodes' zone lists.
      
      online_pages() {
      	build_all_zonelists()
      	.....
      	node_set_state(zone_to_nid(zone), N_HIGH_MEMORY)
      }
      
      Here the node of the zone is put into N_HIGH_MEMORY state after calling
      build_all_zonelists(), but build_all_zonelists() only adds zones from
      nodes in N_HIGH_MEMORY state to the fallback zone lists.
      build_all_zonelists()
      
          ->__build_all_zonelists()
      	->build_zonelists()
      	    ->find_next_best_node()
      		->for_each_node_state(n, N_HIGH_MEMORY)
      
      So memory in the new zone will never be used by other nodes, and it may
      cause strange behavor when system is under memory pressure.  So put node
      into N_HIGH_MEMORY state before calling build_all_zonelists().
      Signed-off-by: default avatarJianguo Wu <wujianguo@huawei.com>
      Signed-off-by: default avatarJiang Liu <liuj97@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Keping Chen <chenkeping@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      08dff7b7
    • Jiang Liu's avatar
      mm/hotplug: correctly setup fallback zonelists when creating new pgdat · 9adb62a5
      Jiang Liu authored
      When hotadd_new_pgdat() is called to create new pgdat for a new node, a
      fallback zonelist should be created for the new node.  There's code to try
      to achieve that in hotadd_new_pgdat() as below:
      
      	/*
      	 * The node we allocated has no zone fallback lists. For avoiding
      	 * to access not-initialized zonelist, build here.
      	 */
      	mutex_lock(&zonelists_mutex);
      	build_all_zonelists(pgdat, NULL);
      	mutex_unlock(&zonelists_mutex);
      
      But it doesn't work as expected.  When hotadd_new_pgdat() is called, the
      new node is still in offline state because node_set_online(nid) hasn't
      been called yet.  And build_all_zonelists() only builds zonelists for
      online nodes as:
      
              for_each_online_node(nid) {
                      pg_data_t *pgdat = NODE_DATA(nid);
      
                      build_zonelists(pgdat);
                      build_zonelist_cache(pgdat);
              }
      
      Though we hope to create zonelist for the new pgdat, but it doesn't.  So
      add a new parameter "pgdat" the build_all_zonelists() to build pgdat for
      the new pgdat too.
      Signed-off-by: default avatarJiang Liu <liuj97@gmail.com>
      Signed-off-by: default avatarXishi Qiu <qiuxishi@huawei.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Keping Chen <chenkeping@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9adb62a5
    • Wanpeng Li's avatar
    • Wanpeng Li's avatar
    • Wanpeng Li's avatar
    • Xishi Qiu's avatar
      mm: setup pageblock_order before it's used by sparsemem · ca57df79
      Xishi Qiu authored
      On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
      Itanium, pageblock_order is a variable with default value of 0.  It's set
      to the right value by set_pageblock_order() in function
      free_area_init_core().
      
      But pageblock_order may be used by sparse_init() before free_area_init_core()
      is called along path:
      sparse_init()
          ->sparse_early_usemaps_alloc_node()
      	->usemap_size()
      	    ->SECTION_BLOCKFLAGS_BITS
      		->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
      NR_PAGEBLOCK_BITS)
      
      The uninitialized pageblock_size will cause memory wasting because
      usemap_size() returns a much bigger value then it's really needed.
      
      For example, on an Itanium platform,
      sparse_init() pageblock_order=0 usemap_size=24576
      free_area_init_core() before pageblock_order=0, usemap_size=24576
      free_area_init_core() after pageblock_order=12, usemap_size=8
      
      That means 24K memory has been wasted for each section, so fix it by calling
      set_pageblock_order() from sparse_init().
      Signed-off-by: default avatarXishi Qiu <qiuxishi@huawei.com>
      Signed-off-by: default avatarJiang Liu <liuj97@gmail.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Keping Chen <chenkeping@huawei.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ca57df79
    • Jeff Liu's avatar
      mm/memory.c:print_vma_addr(): call up_read(&mm->mmap_sem) directly · 51a07e50
      Jeff Liu authored
      Call up_read(&mm->mmap_sem) directly since we have already got mm via
      current->mm at the beginning of print_vma_addr().
      Signed-off-by: default avatarJie Liu <jeff.liu@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      51a07e50
    • Minchan Kim's avatar
      vmscan: remove obsolete shrink_control comment · 8e125cd8
      Minchan Kim authored
      09f363c7 ("vmscan: fix shrinker callback bug in fs/super.c") fixed a
      shrinker callback which was returning -1 when nr_to_scan is zero, which
      caused excessive slab scanning.  But 635697c6 ("vmscan: fix initial
      shrinker size handling") fixed the problem, again so we can freely return
      -1 although nr_to_scan is zero.  So let's revert 09f363c7 because the
      comment added in 09f363c7 made an unnecessary rule.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Mikulas Patocka <mpatocka@redhat.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e125cd8
    • Rabin Vincent's avatar
      mm: CONFIG_HAVE_MEMBLOCK_NODE -> CONFIG_HAVE_MEMBLOCK_NODE_MAP · fe03025d
      Rabin Vincent authored
      0ee332c1 ("memblock: Kill early_node_map[]") wanted to replace
      CONFIG_ARCH_POPULATES_NODE_MAP with CONFIG_HAVE_MEMBLOCK_NODE_MAP but
      ended up replacing one occurence with a reference to the non-existent
      symbol CONFIG_HAVE_MEMBLOCK_NODE.
      
      The resulting omission of code would probably have been causing problems
      to 32-bit machines with memory hotplug.
      Signed-off-by: default avatarRabin Vincent <rabin@rab.in>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fe03025d
    • Rik van Riel's avatar
      mm: have order > 0 compaction start off where it left · 7db8889a
      Rik van Riel authored
      Order > 0 compaction stops when enough free pages of the correct page
      order have been coalesced.  When doing subsequent higher order
      allocations, it is possible for compaction to be invoked many times.
      
      However, the compaction code always starts out looking for things to
      compact at the start of the zone, and for free pages to compact things to
      at the end of the zone.
      
      This can cause quadratic behaviour, with isolate_freepages starting at the
      end of the zone each time, even though previous invocations of the
      compaction code already filled up all free memory on that end of the zone.
      
      This can cause isolate_freepages to take enormous amounts of CPU with
      certain workloads on larger memory systems.
      
      The obvious solution is to have isolate_freepages remember where it left
      off last time, and continue at that point the next time it gets invoked
      for an order > 0 compaction.  This could cause compaction to fail if
      cc->free_pfn and cc->migrate_pfn are close together initially, in that
      case we restart from the end of the zone and try once more.
      
      Forced full (order == -1) compactions are left alone.
      
      [akpm@linux-foundation.org: checkpatch fixes]
      [akpm@linux-foundation.org: s/laste/last/, use 80 cols]
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Reported-by: default avatarJim Schutt <jaschut@sandia.gov>
      Tested-by: default avatarJim Schutt <jaschut@sandia.gov>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7db8889a
    • Wanpeng Li's avatar
      memcg: rename mem_control_xxx to memcg_xxx · ab215884
      Wanpeng Li authored
      Replace memory_cgroup_xxx() with memcg_xxx()
      Signed-off-by: default avatarWanpeng Li <liwp.linux@gmail.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ab215884
    • Glauber Costa's avatar
      memcg: fix bad behavior in use_hierarchy file · 567fb435
      Glauber Costa authored
      I have an application that does the following:
      
      * copy the state of all controllers attached to a hierarchy
      * replicate it as a child of the current level.
      
      I would expect writes to the files to mostly succeed, since they are
      inheriting sane values from parents.
      
      But that is not the case for use_hierarchy.  If it is set to 0, we succeed
      ok.  If we're set to 1, the value of the file is automatically set to 1 in
      the children, but if userspace tries to write the very same 1, it will
      fail.  That same situation happens if we set use_hierarchy, create a
      child, and then try to write 1 again.
      
      Now, there is no reason whatsoever for failing to write a value that is
      already there.  It doesn't even match the comments, that states:
      
       /* If parent's use_hierarchy is set, we can't make any modifications
        * in the child subtrees...
      
      since we are not changing anything.
      
      So test the new value against the one we're storing, and automatically
      return 0 if we're not proposing a change.
      Signed-off-by: default avatarGlauber Costa <glommer@parallels.com>
      Cc: Dhaval Giani <dhaval.giani@gmail.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Ying Han <yinghan@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      567fb435
    • Wanpeng Li's avatar
      mm: remove unused LRU_ALL_EVICTABLE · ca28ddc9
      Wanpeng Li authored
      Signed-off-by: default avatarWanpeng Li <liwp.linux@gmail.com>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ca28ddc9
    • Andrew Morton's avatar
      memcg: rename config variables · c255a458
      Andrew Morton authored
      Sanity:
      
      CONFIG_CGROUP_MEM_RES_CTLR -> CONFIG_MEMCG
      CONFIG_CGROUP_MEM_RES_CTLR_SWAP -> CONFIG_MEMCG_SWAP
      CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED -> CONFIG_MEMCG_SWAP_ENABLED
      CONFIG_CGROUP_MEM_RES_CTLR_KMEM -> CONFIG_MEMCG_KMEM
      
      [mhocko@suse.cz: fix missed bits]
      Cc: Glauber Costa <glommer@parallels.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c255a458
    • Minchan Kim's avatar
      mm: clean up __count_immobile_pages() · 80934513
      Minchan Kim authored
      The __count_immobile_pages() naming is rather awkward.  Choose a more
      clear name and add a comment.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      80934513
    • Minchan Kim's avatar
      mm: do not use page_count() without a page pin · 97d255c8
      Minchan Kim authored
      d179e84b ("mm: vmscan: do not use page_count without a page pin") fixed
      this problem in vmscan.c but same problem is in __count_immobile_pages().
      
      I copy and paste d179e84b's contents for description.
      
      "It is unsafe to run page_count during the physical pfn scan because
      compound_head could trip on a dangling pointer when reading
      page->first_page if the compound page is being freed by another CPU."
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Wanpeng Li <liwp.linux@gmail.com>
      Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      97d255c8
    • David Rientjes's avatar
      mm, oom: replace some information in tasklist dump · de34d965
      David Rientjes authored
      The number of ptes and swap entries are used in the oom killer's badness
      heuristic, so they should be shown in the tasklist dump.
      
      This patch adds those fields and replaces cpu and oom_adj values that are
      currently emitted.  Cpu isn't interesting and oom_adj is deprecated and
      will be removed later this year, the same information is already displayed
      as oom_score_adj which is used internally.
      
      At the same time, make the documentation a little more clear to state this
      information is helpful to determine why the oom killer chose the task it
      did to kill.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      de34d965
    • David Rientjes's avatar
      mm, oom: fix potential killing of thread that is disabled from oom killing · 121d1ba0
      David Rientjes authored
      /proc/sys/vm/oom_kill_allocating_task will immediately kill current when
      the oom killer is called to avoid a potentially expensive tasklist scan
      for large systems.
      
      Currently, however, it is not checking current's oom_score_adj value which
      may be OOM_SCORE_ADJ_MIN, meaning that it has been disabled from oom
      killing.
      
      This patch avoids killing current in such a condition and simply falls
      back to the tasklist scan since memory still needs to be freed.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      121d1ba0
    • KOSAKI Motohiro's avatar
      mm: clear pages_scanned only if draining a pcp adds pages to the buddy allocator again · 2a13515c
      KOSAKI Motohiro authored
      commit 2ff754fa ("mm: clear pages_scanned only if draining a pcp adds
      pages to the buddy allocator again") fixed one free_pcppages_bulk()
      misuse.  But two another miuse still exist.
      
      This patch fixes it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Wu Fengguang <fengguang.wu@intel.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2a13515c
    • KOSAKI Motohiro's avatar
      mm, fadvise: don't return -EINVAL when filesystem cannot implement fadvise() · 3d3727cd
      KOSAKI Motohiro authored
      Eric Wong reported his test suite failex when /tmp is tmpfs.
      
      https://lkml.org/lkml/2012/2/24/479
      
      Currentlt the input check of POSIX_FADV_WILLNEED has two problems.
      
      - requires a_ops->readpage.  But in fact, force_page_cache_readahead()
        requires that the target filesystem has either ->readpage or ->readpages.
      
      - returns -EINVAL when the filesystem doesn't have ->readpage.  But
        posix says that fadvise is merely a hint.  Thus fadvise() should return
        0 if filesystem has no means of implementing fadvise().  The userland
        application should not know nor care whcih type of filesystem backs the
        TMPDIR directory, as Eric pointed out.  There is nothing which userspace
        can do to solve this error.
      
      So change the return value to 0 when filesytem doesn't support readahead.
      
      [akpm@linux-foundation.org: checkpatch fixes]
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Hillf Danton <dhillf@gmail.com>
      Signed-off-by: default avatarEric Wong <normalperson@yhbt.net>
      Tested-by: default avatarEric Wong <normalperson@yhbt.net>
      Reviewed-by: default avatarWanlong Gao <gaowanlong@cn.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3d3727cd
    • Gavin Shan's avatar
      mm/compaction: cleanup on compaction_deferred · c59e2610
      Gavin Shan authored
      When CONFIG_COMPACTION is enabled, compaction_deferred() tries to
      recalculate the deferred limit again, which isn't necessary.
      
      When CONFIG_COMPACTION is disabled, compaction_deferred() should return
      "true" or "false" since it has "bool" for its return value.
      Signed-off-by: default avatarGavin Shan <shangw@linux.vnet.ibm.com>
      Acked-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c59e2610
    • KAMEZAWA Hiroyuki's avatar
      memcg: make mem_cgroup_force_empty_list() return bool · 3c935d18
      KAMEZAWA Hiroyuki authored
      mem_cgroup_force_empty_list() just returns 0 or -EBUSY and -EBUSY
      indicates 'you need to retry'.  Make mem_cgroup_force_empty_list() return
      a bool to simplify the logic.
      
      [akpm@linux-foundation.org: rework mem_cgroup_force_empty_list()'s comment]
      Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3c935d18
    • KAMEZAWA Hiroyuki's avatar
      memcg: mem_cgroup_move_parent() doesn't need gfp_mask · 6068bf01
      KAMEZAWA Hiroyuki authored
      Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6068bf01