Commit Graph

297 Commits

Author SHA1 Message Date
KAMEZAWA Hiroyuki
26174efd42 memcg: generic filestat update interface
This patch extracts the core logic from mem_cgroup_update_file_mapped() as
mem_cgroup_update_file_stat() and adds a wrapper.

As a planned future update, memory cgroup has to count dirty pages to
implement dirty_ratio/limit.  And more, the number of dirty pages is
required to kick flusher thread to start writeback.  (Now, no kick.)

This patch is preparation for it and makes other statistics implementation
clearer.  Just a clean up.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Greg Thelen <gthelen@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:10 -07:00
KAMEZAWA Hiroyuki
1489ebad8b memcg: cpu hotplug aware quick acount_move detection
An event counter MEM_CGROUP_ON_MOVE is used for quick check whether file
stat update can be done in async manner or not.  Now, it use percpu
counter and for_each_possible_cpu to update.

This patch replaces for_each_possible_cpu to for_each_online_cpu and adds
necessary synchronization logic at CPU HOTPLUG.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki
711d3d2c9b memcg: cpu hotplug aware percpu count updates
Now, memcgroup's per cpu coutner uses for_each_possible_cpu() to get the
value.  It's better to use for_each_online_cpu() and a cpu hotplug
handler.

This patch only handles statistics counter.  MEM_CGROUP_ON_MOVE will be
handled in another patch.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki
7d74b06f24 memcg: use for_each_mem_cgroup
In memory cgroup management, we sometimes have to walk through
subhierarchy of cgroup to gather informaiton, or lock something, etc.

Now, to do that, mem_cgroup_walk_tree() function is provided.  It calls
given callback function per cgroup found.  But the bad thing is that it
has to pass a fixed style function and argument, "void*" and it adds much
type casting to memcontrol.c.

To make the code clean, this patch replaces walk_tree() with

  for_each_mem_cgroup_tree(iter, root)

An iterator style call.  The good point is that iterator call doesn't have
to assume what kind of function is called under it.  A bad point is that
it may cause reference-count leak if a caller use "break" from the loop by
mistake.

I think the benefit is larger.  The modified code seems straigtforward and
easy to read because we don't have misterious callbacks and pointer cast.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki
32047e2a85 memcg: avoid lock in updating file_mapped (Was fix race in file_mapped accouting flag management
At accounting file events per memory cgroup, we need to find memory cgroup
via page_cgroup->mem_cgroup.  Now, we use lock_page_cgroup() for guarantee
pc->mem_cgroup is not overwritten while we make use of it.

But, considering the context which page-cgroup for files are accessed,
we can use alternative light-weight mutual execusion in the most case.

At handling file-caches, the only race we have to take care of is "moving"
account, IOW, overwriting page_cgroup->mem_cgroup.  (See comment in the
patch)

Unlike charge/uncharge, "move" happens not so frequently. It happens only when
rmdir() and task-moving (with a special settings.)
This patch adds a race-checker for file-cache-status accounting v.s. account
moving. The new per-cpu-per-memcg counter MEM_CGROUP_ON_MOVE is added.
The routine for account move
  1. Increment it before start moving
  2. Call synchronize_rcu()
  3. Decrement it after the end of moving.
By this, file-status-counting routine can check it needs to call
lock_page_cgroup(). In most case, I doesn't need to call it.

Following is a perf data of a process which mmap()/munmap 32MB of file cache
in a minute.

Before patch:
    28.25%     mmap  mmap               [.] main
    22.64%     mmap  [kernel.kallsyms]  [k] page_fault
     9.96%     mmap  [kernel.kallsyms]  [k] mem_cgroup_update_file_mapped
     3.67%     mmap  [kernel.kallsyms]  [k] filemap_fault
     3.50%     mmap  [kernel.kallsyms]  [k] unmap_vmas
     2.99%     mmap  [kernel.kallsyms]  [k] __do_fault
     2.76%     mmap  [kernel.kallsyms]  [k] find_get_page

After patch:
    30.00%     mmap  mmap               [.] main
    23.78%     mmap  [kernel.kallsyms]  [k] page_fault
     5.52%     mmap  [kernel.kallsyms]  [k] mem_cgroup_update_file_mapped
     3.81%     mmap  [kernel.kallsyms]  [k] unmap_vmas
     3.26%     mmap  [kernel.kallsyms]  [k] find_get_page
     3.18%     mmap  [kernel.kallsyms]  [k] __do_fault
     3.03%     mmap  [kernel.kallsyms]  [k] filemap_fault
     2.40%     mmap  [kernel.kallsyms]  [k] handle_mm_fault
     2.40%     mmap  [kernel.kallsyms]  [k] do_page_fault

This patch reduces memcg's cost to some extent.
(mem_cgroup_update_file_mapped is called by both of map/unmap)

Note: It seems some more improvements are required..but no idea.
      maybe removing set/unset flag is required.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.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>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki
0c270f8f99 memcg: fix race in file_mapped accouting flag management
Presently memory cgroup accounts file-mapped by counter and flag.  counter
is working in the same way with zone_stat but FileMapped flag only exists
in memcg (for helping move_account).

This flag can be updated wrongly in a case.  Assume CPU0 and CPU1 and a
thread mapping a page on CPU0, another thread unmapping it on CPU1.

    CPU0                   		CPU1
				rmv rmap (mapcount 1->0)
   add rmap (mapcount 0->1)
   lock_page_cgroup()
   memcg counter+1		(some delay)
   set MAPPED FLAG.
   unlock_page_cgroup()
				lock_page_cgroup()
				memcg counter-1
				clear MAPPED flag

In the above sequence counter is properly updated but FLAG is not.  This
means that representing a state by a flag which is maintained by counter
needs some special care.

To handle this, when clearing a flag, this patch check mapcount directly
and clear the flag only when mapcount == 0.  (if mapcount >0, someone will
make it to zero later and flag will be cleared.)

Reverse case, dec-after-inc cannot be a problem because page_table_lock()
works well for it.  (IOW, to make above sequence, 2 processes should touch
the same page at once with map/unmap.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
Kirill A. Shutemov
ad4ca5f4b7 memcg: fix thresholds with use_hierarchy == 1
We need to check parent's thresholds if parent has use_hierarchy == 1 to
be sure that parent's threshold events will be triggered even if parent
itself is not active (no MEM_CGROUP_EVENTS).

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-07 13:31:21 -07:00
KOSAKI Motohiro
13d7e3a2db memcg: convert to use zone_to_nid() from bare zone->zone_pgdat->node_id
We have zone_to_nid().  this patch convert all existing users of
zone->zone_pgdat->node_id.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KOSAKI Motohiro
00918b6ab8 memcg: remove nid and zid argument from mem_cgroup_soft_limit_reclaim()
mem_cgroup_soft_limit_reclaim() has zone, nid and zid argument.  but nid
and zid can be calculated from zone.  So remove it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KOSAKI Motohiro
14fec79680 memcg: mem_cgroup_shrink_node_zone() doesn't need sc.nodemask
Currently mem_cgroup_shrink_node_zone() call shrink_zone() directly.  thus
it doesn't need to initialize sc.nodemask because shrink_zone() doesn't
use it at all.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KAMEZAWA Hiroyuki
f75ca96203 memcg: avoid css_get()
Now, memory cgroup increments css(cgroup subsys state)'s reference count
per a charged page.  And the reference count is kept until the page is
uncharged.  But this has 2 bad effect.

 1. Because css_get/put calls atomic_inc()/dec, heavy call of them
    on large smp will not scale well.
 2. Because css's refcnt cannot be in a state as "ready-to-release",
    cgroup's notify_on_release handler can't work with memcg.
 3. css's refcnt is atomic_t, it means smaller than 32bit. Maybe too small.

This has been a problem since the 1st merge of memcg.

This is a trial to remove css's refcnt per a page. Even if we remove
refcnt, pre_destroy() does enough synchronization as
  - check res->usage == 0.
  - check no pages on LRU.

This patch removes css's refcnt per page.  Even after this patch, at the
1st look, it seems css_get() is still called in try_charge().

But the logic is.

  - If a memcg of mm->owner is cached one, consume_stock() will work.
    At success, return immediately.
  - If consume_stock returns false, css_get() is called and go to
    slow path which may be blocked. At the end of slow path,
    css_put() is called and restart from the start if necessary.

So, in the fast path, we don't call css_get() and can avoid access to
shared counter. This patch can make the most possible case fast.

Here is a result of multi-threaded page fault benchmark.

[Before]
    25.32%  multi-fault-all  [kernel.kallsyms]      [k] clear_page_c
     9.30%  multi-fault-all  [kernel.kallsyms]      [k] _raw_spin_lock_irqsave
     8.02%  multi-fault-all  [kernel.kallsyms]      [k] try_get_mem_cgroup_from_mm <=====(*)
     7.83%  multi-fault-all  [kernel.kallsyms]      [k] down_read_trylock
     5.38%  multi-fault-all  [kernel.kallsyms]      [k] __css_put
     5.29%  multi-fault-all  [kernel.kallsyms]      [k] __alloc_pages_nodemask
     4.92%  multi-fault-all  [kernel.kallsyms]      [k] _raw_spin_lock_irq
     4.24%  multi-fault-all  [kernel.kallsyms]      [k] up_read
     3.53%  multi-fault-all  [kernel.kallsyms]      [k] css_put
     2.11%  multi-fault-all  [kernel.kallsyms]      [k] handle_mm_fault
     1.76%  multi-fault-all  [kernel.kallsyms]      [k] __rmqueue
     1.64%  multi-fault-all  [kernel.kallsyms]      [k] __mem_cgroup_commit_charge

[After]
    28.41%  multi-fault-all  [kernel.kallsyms]      [k] clear_page_c
    10.08%  multi-fault-all  [kernel.kallsyms]      [k] _raw_spin_lock_irq
     9.58%  multi-fault-all  [kernel.kallsyms]      [k] down_read_trylock
     9.38%  multi-fault-all  [kernel.kallsyms]      [k] _raw_spin_lock_irqsave
     5.86%  multi-fault-all  [kernel.kallsyms]      [k] __alloc_pages_nodemask
     5.65%  multi-fault-all  [kernel.kallsyms]      [k] up_read
     2.82%  multi-fault-all  [kernel.kallsyms]      [k] handle_mm_fault
     2.64%  multi-fault-all  [kernel.kallsyms]      [k] mem_cgroup_add_lru_list
     2.48%  multi-fault-all  [kernel.kallsyms]      [k] __mem_cgroup_commit_charge

Then, 8.02% of try_get_mem_cgroup_from_mm() disappears because this patch
removes css_tryget() in it. (But yes, this is an extreme case.)

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KAMEZAWA Hiroyuki
158e0a2d1b memcg: use find_lock_task_mm() in memory cgroups oom
When the OOM killer scans task, it check a task is under memcg or
not when it's called via memcg's context.

But, as Oleg pointed out, a thread group leader may have NULL ->mm
and task_in_mem_cgroup() may do wrong decision. We have to use
find_lock_task_mm() in memcg as generic OOM-Killer does.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
Daisuke Nishimura
73045c47b6 memcg: remove mem from arg of charge_common
mem_cgroup_charge_common() is always called with @mem = NULL, so it's
meaningless.  This patch removes it.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
Daisuke Nishimura
bd0d24bfe8 memcg: remove redundant code
- try_get_mem_cgroup_from_mm() calls rcu_read_lock/unlock by itself, so we
  don't have to call them in task_in_mem_cgroup().
- *mz is not used in __mem_cgroup_uncharge_common().
- we don't have to call lookup_page_cgroup() in mem_cgroup_end_migration()
  after we've cleared PCG_MIGRATION of @oldpage.
- remove empty comment.
- remove redundant empty line in mem_cgroup_cache_charge().

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:18 -07:00
KAMEZAWA Hiroyuki
2bd9bb206b memcg: clean up waiting move acct
Now, for checking a memcg is under task-account-moving, we do css_tryget()
against mc.to and mc.from.  But this is just complicating things.  This
patch makes the check easier.

This patch adds a spinlock to move_charge_struct and guard modification of
mc.to and mc.from.  By this, we don't have to think about complicated
races arount this not-critical path.

[balbir@linux.vnet.ibm.com: don't crash on a null memcg being passed]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:18 -07:00
KAMEZAWA Hiroyuki
4b53433468 memcg: clean up try_charge main loop
mem_cgroup_try_charge() has a big loop in it and seems to be hard to read.
 Most of routines are for slow path.  This patch moves codes out from the
loop and make it clear what's done.

Summary:
 - refactoring a function to detect a memcg is under acccount move or not.
 - refactoring a function to wait for the end of moving task acct.
 - refactoring a main loop('s slow path) as a function and make it clear
   why we retry or quit by return code.
 - add fatal_signal_pending() check for bypassing charge loops.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:18 -07:00
KOSAKI Motohiro
cc8e970c3c memcg: add mm_vmscan_memcg_isolate tracepoint
Memcg also need to trace page isolation information as global reclaim.
This patch does it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:45:03 -07:00
David Rientjes
a63d83f427 oom: badness heuristic rewrite
This a complete rewrite of the oom killer's badness() heuristic which is
used to determine which task to kill in oom conditions.  The goal is to
make it as simple and predictable as possible so the results are better
understood and we end up killing the task which will lead to the most
memory freeing while still respecting the fine-tuning from userspace.

Instead of basing the heuristic on mm->total_vm for each task, the task's
rss and swap space is used instead.  This is a better indication of the
amount of memory that will be freeable if the oom killed task is chosen
and subsequently exits.  This helps specifically in cases where KDE or
GNOME is chosen for oom kill on desktop systems instead of a memory
hogging task.

The baseline for the heuristic is a proportion of memory that each task is
currently using in memory plus swap compared to the amount of "allowable"
memory.  "Allowable," in this sense, means the system-wide resources for
unconstrained oom conditions, the set of mempolicy nodes, the mems
attached to current's cpuset, or a memory controller's limit.  The
proportion is given on a scale of 0 (never kill) to 1000 (always kill),
roughly meaning that if a task has a badness() score of 500 that the task
consumes approximately 50% of allowable memory resident in RAM or in swap
space.

The proportion is always relative to the amount of "allowable" memory and
not the total amount of RAM systemwide so that mempolicies and cpusets may
operate in isolation; they shall not need to know the true size of the
machine on which they are running if they are bound to a specific set of
nodes or mems, respectively.

Root tasks are given 3% extra memory just like __vm_enough_memory()
provides in LSMs.  In the event of two tasks consuming similar amounts of
memory, it is generally better to save root's task.

Because of the change in the badness() heuristic's baseline, it is also
necessary to introduce a new user interface to tune it.  It's not possible
to redefine the meaning of /proc/pid/oom_adj with a new scale since the
ABI cannot be changed for backward compatability.  Instead, a new tunable,
/proc/pid/oom_score_adj, is added that ranges from -1000 to +1000.  It may
be used to polarize the heuristic such that certain tasks are never
considered for oom kill while others may always be considered.  The value
is added directly into the badness() score so a value of -500, for
example, means to discount 50% of its memory consumption in comparison to
other tasks either on the system, bound to the mempolicy, in the cpuset,
or sharing the same memory controller.

/proc/pid/oom_adj is changed so that its meaning is rescaled into the
units used by /proc/pid/oom_score_adj, and vice versa.  Changing one of
these per-task tunables will rescale the value of the other to an
equivalent meaning.  Although /proc/pid/oom_adj was originally defined as
a bitshift on the badness score, it now shares the same linear growth as
/proc/pid/oom_score_adj but with different granularity.  This is required
so the ABI is not broken with userspace applications and allows oom_adj to
be deprecated for future removal.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:45:02 -07:00
KOSAKI Motohiro
25edde0332 vmscan: kill prev_priority completely
Since 2.6.28 zone->prev_priority is unused. Then it can be removed
safely. It reduce stack usage slightly.

Now I have to say that I'm sorry. 2 years ago, I thought prev_priority
can be integrate again, it's useful. but four (or more) times trying
haven't got good performance number. Thus I give up such approach.

The rest of this changelog is notes on prev_priority and why it existed in
the first place and why it might be not necessary any more. This information
is based heavily on discussions between Andrew Morton, Rik van Riel and
Kosaki Motohiro who is heavily quotes from.

Historically prev_priority was important because it determined when the VM
would start unmapping PTE pages. i.e. there are no balances of note within
the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there
is a potential risk of unnecessarily increasing minor faults as a large
amount of read activity of use-once pages could push mapped pages to the
end of the LRU and get unmapped.

There is no proof this is still a problem but currently it is not considered
to be. Active files are not deactivated if the active file list is smaller
than the inactive list reducing the liklihood that file-mapped pages are
being pushed off the LRU and referenced executable pages are kept on the
active list to avoid them getting pushed out by read activity.

Even if it is a problem, prev_priority prev_priority wouldn't works
nowadays. First of all, current vmscan still a lot of UP centric code. it
expose some weakness on some dozens CPUs machine. I think we need more and
more improvement.

The problem is, current vmscan mix up per-system-pressure, per-zone-pressure
and per-task-pressure a bit. example, prev_priority try to boost priority to
other concurrent priority. but if the another task have mempolicy restriction,
it is unnecessary, but also makes wrong big latency and exceeding reclaim.
per-task based priority + prev_priority adjustment make the emulation of
per-system pressure. but it have two issue 1) too rough and brutal emulation
2) we need per-zone pressure, not per-system.

Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about
2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer.
but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the
system have higher memory pressure than priority==0 (1/4096*10,000 > 2).
prev_priority can't solve such multithreads workload issue. In other word,
prev_priority concept assume the sysmtem don't have lots threads."

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:45:00 -07:00
KAMEZAWA Hiroyuki
4d845ebf4c memcg: fix wake up in oom wait queue
OOM-waitqueue should be waken up when oom_disable is canceled.  This is a
fix for 3c11ecf448 ("memcg: oom kill disable and oom status").

How to test:
 Create a cgroup A...
 1. set memory.limit and memory.memsw.limit to be small value
 2. echo 1 > /cgroup/A/memory.oom_control, this disables oom-kill.
 3. run a program which must cause OOM.

A program executed in 3 will sleep by oom_waiqueue in memcg.  Then, how to
wake it up is problem.

 1. echo 0 > /cgroup/A/memory.oom_control (enable OOM-killer)
 2. echo big mem > /cgroup/A/memory.memsw.limit_in_bytes(allow more swap)

etc..

Without the patch, a task in slept can not be waken up.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-29 15:29:30 -07:00
Kirill A. Shutemov
2c488db27b memcg: clean up memory thresholds
Introduce struct mem_cgroup_thresholds.  It helps to reduce number of
checks of thresholds type (memory or mem+swap).

[akpm@linux-foundation.org: repair comment]
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Kirill A. Shutemov
907860ed38 cgroups: make cftype.unregister_event() void-returning
Since we are unable to handle an error returned by
cftype.unregister_event() properly, let's make the callback
void-returning.

mem_cgroup_unregister_event() has been rewritten to be a "never fail"
function.  On mem_cgroup_usage_register_event() we save old buffer for
thresholds array and reuse it in mem_cgroup_usage_unregister_event() to
avoid allocation.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
akpm@linux-foundation.org
ac39cf8cb8 memcg: fix mis-accounting of file mapped racy with migration
FILE_MAPPED per memcg of migrated file cache is not properly updated,
because our hook in page_add_file_rmap() can't know to which memcg
FILE_MAPPED should be counted.

Basically, this patch is for fixing the bug but includes some big changes
to fix up other messes.

Now, at migrating mapped file, events happen in following sequence.

 1. allocate a new page.
 2. get memcg of an old page.
 3. charge ageinst a new page before migration. But at this point,
    no changes to new page's page_cgroup, no commit for the charge.
    (IOW, PCG_USED bit is not set.)
 4. page migration replaces radix-tree, old-page and new-page.
 5. page migration remaps the new page if the old page was mapped.
 6. Here, the new page is unlocked.
 7. memcg commits the charge for newpage, Mark the new page's page_cgroup
    as PCG_USED.

Because "commit" happens after page-remap, we can count FILE_MAPPED
at "5", because we should avoid to trust page_cgroup->mem_cgroup.
if PCG_USED bit is unset.
(Note: memcg's LRU removal code does that but LRU-isolation logic is used
 for helping it. When we overwrite page_cgroup->mem_cgroup, page_cgroup is
 not on LRU or page_cgroup->mem_cgroup is NULL.)

We can lose file_mapped accounting information at 5 because FILE_MAPPED
is updated only when mapcount changes 0->1. So we should catch it.

BTW, historically, above implemntation comes from migration-failure
of anonymous page. Because we charge both of old page and new page
with mapcount=0, we can't catch
  - the page is really freed before remap.
  - migration fails but it's freed before remap
or .....corner cases.

New migration sequence with memcg is:

 1. allocate a new page.
 2. mark PageCgroupMigration to the old page.
 3. charge against a new page onto the old page's memcg. (here, new page's pc
    is marked as PageCgroupUsed.)
 4. page migration replaces radix-tree, page table, etc...
 5. At remapping, new page's page_cgroup is now makrked as "USED"
    We can catch 0->1 event and FILE_MAPPED will be properly updated.

    And we can catch SWAPOUT event after unlock this and freeing this
    page by unmap() can be caught.

 7. Clear PageCgroupMigration of the old page.

So, FILE_MAPPED will be correctly updated.

Then, for what MIGRATION flag is ?
  Without it, at migration failure, we may have to charge old page again
  because it may be fully unmapped. "charge" means that we have to dive into
  memory reclaim or something complated. So, it's better to avoid
  charge it again. Before this patch, __commit_charge() was working for
  both of the old/new page and fixed up all. But this technique has some
  racy condtion around FILE_MAPPED and SWAPOUT etc...
  Now, the kernel use MIGRATION flag and don't uncharge old page until
  the end of migration.

I hope this change will make memcg's page migration much simpler.  This
page migration has caused several troubles.  Worth to add a flag for
simplification.

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Phil Carmody
315c1998e1 mm: memcontrol - uninitialised return value
Only an out of memory error will cause ret to be set.

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Phil Carmody
5407a56257 mm: remove unnecessary use of atomic
The bottom 4 hunks are atomically changing memory to which there are no
aliases as it's freshly allocated, so there's no need to use atomic
operations.

The other hunks are just atomic_read and atomic_set, and do not involve
any read-modify-write.  The use of atomic_{read,set} doesn't prevent a
read/write or write/write race, so if a race were possible (I'm not saying
one is), then it would still be there even with atomic_set.

See:
http://digitalvampire.org/blog/index.php/2007/05/13/atomic-cargo-cults/

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
Daisuke Nishimura
87946a7228 memcg: move charge of file pages
This patch adds support for moving charge of file pages, which include
normal file, tmpfs file and swaps of tmpfs file.  It's enabled by setting
bit 1 of <target cgroup>/memory.move_charge_at_immigrate.

Unlike the case of anonymous pages, file pages(and swaps) in the range
mmapped by the task will be moved even if the task hasn't done page fault,
i.e.  they might not be the task's "RSS", but other task's "RSS" that maps
the same file.  And mapcount of the page is ignored(the page can be moved
even if page_mapcount(page) > 1).  So, conditions that the page/swap
should be met to be moved is that it must be in the range mmapped by the
target task and it must be charged to the old cgroup.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
Daisuke Nishimura
90254a6583 memcg: clean up move charge
This patch cleans up move charge code by:

- define functions to handle pte for each types, and make
  is_target_pte_for_mc() cleaner.

- instead of checking the MOVE_CHARGE_TYPE_ANON bit, define a function
  that checks the bit.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
KAMEZAWA Hiroyuki
3c11ecf448 memcg: oom kill disable and oom status
This adds a feature to disable oom-killer for memcg, if disabled, of
course, tasks under memcg will stop.

But now, we have oom-notifier for memcg.  And the world around memcg is
not under out-of-memory.  memcg's out-of-memory just shows memcg hits
limit.  Then, administrator or management daemon can recover the situation
by

	- kill some process
	- enlarge limit, add more swap.
	- migrate some tasks
	- remove file cache on tmps (difficult ?)

Unlike oom-killer, you can take enough information before killing tasks.
(by gcore, or, ps etc.)

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
KAMEZAWA Hiroyuki
9490ff2756 memcg: oom notifier
Considering containers or other resource management softwares in userland,
event notification of OOM in memcg should be implemented.  Now, memcg has
"threshold" notifier which uses eventfd, we can make use of it for oom
notification.

This patch adds oom notification eventfd callback for memcg.  The usage is
very similar to threshold notifier, but control file is memory.oom_control
and no arguments other than eventfd is required.

	% cgroup_event_notifier /cgroup/A/memory.oom_control dummy
	(About cgroup_event_notifier, see Documentation/cgroup/)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
KAMEZAWA Hiroyuki
dc98df5a1b memcg: oom wakeup filter
memcg's oom waitqueue is a system-wide wait_queue (for handling
hierarchy.) So, it's better to add custom wake function and do filtering
in wake up path.

This patch adds a filtering feature for waking up oom-waiters.  Hierarchy
is properly handled.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:43 -07:00
Linus Torvalds
f39d01be4c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (44 commits)
  vlynq: make whole Kconfig-menu dependant on architecture
  add descriptive comment for TIF_MEMDIE task flag declaration.
  EEPROM: max6875: Header file cleanup
  EEPROM: 93cx6: Header file cleanup
  EEPROM: Header file cleanup
  agp: use NULL instead of 0 when pointer is needed
  rtc-v3020: make bitfield unsigned
  PCI: make bitfield unsigned
  jbd2: use NULL instead of 0 when pointer is needed
  cciss: fix shadows sparse warning
  doc: inode uses a mutex instead of a semaphore.
  uml: i386: Avoid redefinition of NR_syscalls
  fix "seperate" typos in comments
  cocbalt_lcdfb: correct sections
  doc: Change urls for sparse
  Powerpc: wii: Fix typo in comment
  i2o: cleanup some exit paths
  Documentation/: it's -> its where appropriate
  UML: Fix compiler warning due to missing task_struct declaration
  UML: add kernel.h include to signal.c
  ...
2010-05-20 09:20:59 -07:00
KAMEZAWA Hiroyuki
747388d78a memcg: fix css_is_ancestor() RCU locking
Some callers (in memcontrol.c) calls css_is_ancestor() without
rcu_read_lock.  Because css_is_ancestor() has to access RCU protected
data, it should be under rcu_read_lock().

This makes css_is_ancestor() itself does safe access to RCU protected
area.  (At least, "root" can have refcnt==0 if it's not an ancestor of
"child".  So, we need rcu_read_lock().)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-11 17:33:42 -07:00
KAMEZAWA Hiroyuki
7f0f154641 memcg: fix css_id() RCU locking for real
Commit ad4ba37537 ("memcg: css_id() must be
called under rcu_read_lock()") modifies memcontol.c for fixing RCU check
message.  But Andrew Morton pointed out that the fix doesn't seems sane
and it was just for hidining lockdep messages.

This is a patch for do proper things.  Checking again, all places,
accessing without rcu_read_lock, that commit fixies was intentional....
all callers of css_id() has reference count on it.  So, it's not necessary
to be under rcu_read_lock().

Considering again, we can use rcu_dereference_check for css_id().  We know
css->id is valid if css->refcnt > 0.  (css->id never changes and freed
after css->refcnt going to be 0.)

This patch makes use of rcu_dereference_check() in css_id/depth and remove
unnecessary rcu-read-lock added by the commit.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-11 17:33:42 -07:00
Linus Torvalds
91bc482ec5 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: create rcu_my_thread_group_empty() wrapper
  memcg: css_id() must be called under rcu_read_lock()
  cgroup: Check task_lock in task_subsys_state()
  sched: Fix an RCU warning in print_task()
  cgroup: Fix an RCU warning in alloc_css_id()
  cgroup: Fix an RCU warning in cgroup_path()
  KEYS: Fix an RCU warning in the reading of user keys
  KEYS: Fix an RCU warning
2010-05-07 13:58:21 -07:00
Paul E. McKenney
ad4ba37537 memcg: css_id() must be called under rcu_read_lock()
This patch fixes task_in_mem_cgroup(), mem_cgroup_uncharge_swapcache(),
mem_cgroup_move_swap_account(), and is_target_pte_for_mc() to protect
calls to css_id().  An additional RCU lockdep splat was reported for
memcg_oom_wake_function(), however, this function is not yet in
mainline as of 2.6.34-rc5.

Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
2010-05-04 09:25:03 -07:00
Andrea Arcangeli
93d5c9be1d memcg: fix prepare migration
If a signal is pending (task being killed by sigkill)
__mem_cgroup_try_charge will write NULL into &mem, and css_put will oops
on null pointer dereference.

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
  IP: [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0
  PGD a5d89067 PUD a5d8a067 PMD 0
  Oops: 0000 [#1] SMP
  last sysfs file: /sys/devices/platform/microcode/firmware/microcode/loading
  CPU 0
  Modules linked in: nfs lockd nfs_acl auth_rpcgss sunrpc acpi_cpufreq pcspkr sg [last unloaded: microcode]

  Pid: 5299, comm: largepages Tainted: G        W  2.6.34-rc3 #3 Penryn1600SLI-110dB/To Be Filled By O.E.M.
  RIP: 0010:[<ffffffff810fc6cc>]  [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0

[nishimura@mxp.nes.nec.co.jp: fix merge issues]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-24 11:31:24 -07:00
Jiri Kosina
6c9468e9eb Merge branch 'master' into for-next 2010-04-23 02:08:44 +02:00
KAMEZAWA Hiroyuki
8725d54162 memcg: fix race in file_mapped accounting
Presently, memcg's FILE_MAPPED accounting has following race with
move_account (happens at rmdir()).

    increment page->mapcount (rmap.c)
    mem_cgroup_update_file_mapped()           move_account()
					      lock_page_cgroup()
					      check page_mapped() if
					      page_mapped(page)>1 {
						FILE_MAPPED -1 from old memcg
						FILE_MAPPED +1 to old memcg
					      }
					      .....
					      overwrite pc->mem_cgroup
					      unlock_page_cgroup()
    lock_page_cgroup()
    FILE_MAPPED + 1 to pc->mem_cgroup
    unlock_page_cgroup()

Then,
	old memcg (-1 file mapped)
	new memcg (+2 file mapped)

This happens because move_account see page_mapped() which is not guarded
by lock_page_cgroup().  This patch adds FILE_MAPPED flag to page_cgroup
and move account information based on it.  Now, all checks are synchronous
with lock_page_cgroup().

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Andrea Righi <arighi@develer.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>
2010-04-07 08:38:05 -07:00
Dan Carpenter
e7bbcdf374 memcontrol: fix potential null deref
There was a potential null deref introduced in c62b1a3b31 ("memcg: use
generic percpu instead of private implementation").

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:19 -07:00
Daisuke Nishimura
5cfb80a73b memcg: disable move charge in no mmu case
In commit 02491447 ("memcg: move charges of anonymous swap"), I tried to
disable move charge feature in no mmu case by enclosing all the related
functions with "#ifdef CONFIG_MMU", but the commit places these ifdefs in
wrong place.  (it seems that it's mangled while handling some fixes...)

This patch fixes it up.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:19 -07:00
Greg Thelen
320cc51d90 mm: fix typo in refill_stock() comment
Change refill_stock() comment: s/consumt_stock()/consume_stock()/

Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-03-15 15:27:28 +01:00
KAMEZAWA Hiroyuki
867578cbcc memcg: fix oom kill behavior
In current page-fault code,

	handle_mm_fault()
		-> ...
		-> mem_cgroup_charge()
		-> map page or handle error.
	-> check return code.

If page fault's return code is VM_FAULT_OOM, page_fault_out_of_memory() is
called.  But if it's caused by memcg, OOM should have been already
invoked.

Then, I added a patch: a636b327f7.  That
patch records last_oom_jiffies for memcg's sub-hierarchy and prevents
page_fault_out_of_memory from being invoked in near future.

But Nishimura-san reported that check by jiffies is not enough when the
system is terribly heavy.

This patch changes memcg's oom logic as.
 * If memcg causes OOM-kill, continue to retry.
 * remove jiffies check which is used now.
 * add memcg-oom-lock which works like perzone oom lock.
 * If current is killed(as a process), bypass charge.

Something more sophisticated can be added but this pactch does
fundamental things.
TODO:
 - add oom notifier
 - add permemcg disable-oom-kill flag and freezer at oom.
 - more chances for wake up oom waiter (when changing memory limit etc..)

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:38 -08:00
Kirill A. Shutemov
a0a4db548e cgroups: remove events before destroying subsystem state objects
Events should be removed after rmdir of cgroup directory, but before
destroying subsystem state objects.  Let's take reference to cgroup
directory dentry to do that.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
KAMEZAWA Hiroyuki
d2265e6fa3 memcg : share event counter rather than duplicate
Memcg has 2 eventcountes which counts "the same" event.  Just usages are
different from each other.  This patch tries to reduce event counter.

Now logic uses "only increment, no reset" counter and masks for each
checks.  Softlimit chesk was done per 1000 evetns.  So, the similar check
can be done by !(new_counter & 0x3ff).  Threshold check was done per 100
events.  So, the similar check can be done by (!new_counter & 0x7f)

ALL event checks are done right after EVENT percpu counter is updated.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
KAMEZAWA Hiroyuki
430e48631e memcg: update threshold and softlimit at commit
Presently, move_task does "batched" precharge.  Because res_counter or
css's refcnt are not-scalable jobs for memcg, try_charge_()..  tend to be
done in batched manner if allowed.

Now, softlimit and threshold check their event counter in try_charge, but
the charge is not a per-page event.  And event counter is not updated at
charge().  Moreover, precharge doesn't pass "page" to try_charge() and
softlimit tree will be never updated until uncharge() causes an event."

So the best place to check the event counter is commit_charge().  This is
per-page event by its nature.  This patch move checks to there.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
KAMEZAWA Hiroyuki
c62b1a3b31 memcg: use generic percpu instead of private implementation
When per-cpu counter for memcg was implemneted, dynamic percpu allocator
was not very good.  But now, we have good one and useful macros.  This
patch replaces memcg's private percpu counter implementation with generic
dynamic percpu allocator.

The benefits are
	- We can remove private implementation.
	- The counters will be NUMA-aware. (Current one is not...)
	- This patch makes sizeof struct mem_cgroup smaller. Then,
	  struct mem_cgroup may be fit in page size on small config.
        - About basic performance aspects, see below.

 [Before]
 # size mm/memcontrol.o
   text    data     bss     dec     hex filename
  24373    2528    4132   31033    7939 mm/memcontrol.o

 [page-fault-throuput test on 8cpu/SMP in root cgroup]
 # /root/bin/perf stat -a -e page-faults,cache-misses --repeat 5 ./multi-fault-fork 8

 Performance counter stats for './multi-fault-fork 8' (5 runs):

       45878618  page-faults                ( +-   0.110% )
      602635826  cache-misses               ( +-   0.105% )

   61.005373262  seconds time elapsed   ( +-   0.004% )

 Then cache-miss/page fault = 13.14

 [After]
 #size mm/memcontrol.o
   text    data     bss     dec     hex filename
  23913    2528    4132   30573    776d mm/memcontrol.o
 # /root/bin/perf stat -a -e page-faults,cache-misses --repeat 5 ./multi-fault-fork 8

 Performance counter stats for './multi-fault-fork 8' (5 runs):

       48179400  page-faults                ( +-   0.271% )
      588628407  cache-misses               ( +-   0.136% )

   61.004615021  seconds time elapsed   ( +-   0.004% )

  Then cache-miss/page fault = 12.22

 Text size is reduced.
 This performance improvement is not big and will be invisible in real world
 applications. But this result shows this patch has some good effect even
 on (small) SMP.

Here is a test program I used.

 1. fork() processes on each cpus.
 2. do page fault repeatedly on each process.
 3. after 60secs, kill all childredn and exit.

(3 is necessary for getting stable data, this is improvement from previous one.)

#define _GNU_SOURCE
#include <stdio.h>
#include <sched.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>

/*
 * For avoiding contention in page table lock, FAULT area is
 * sparse. If FAULT_LENGTH is too large for your cpus, decrease it.
 */
#define FAULT_LENGTH	(2 * 1024 * 1024)
#define PAGE_SIZE	4096
#define MAXNUM		(128)

void alarm_handler(int sig)
{
}

void *worker(int cpu, int ppid)
{
	void *start, *end;
	char *c;
	cpu_set_t set;
	int i;

	CPU_ZERO(&set);
	CPU_SET(cpu, &set);
	sched_setaffinity(0, sizeof(set), &set);

	start = mmap(NULL, FAULT_LENGTH, PROT_READ|PROT_WRITE,
			MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
	if (start == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}
	end = start + FAULT_LENGTH;

	pause();
	//fprintf(stderr, "run%d", cpu);
	while (1) {
		for (c = (char*)start; (void *)c < end; c += PAGE_SIZE)
			*c = 0;
		madvise(start, FAULT_LENGTH, MADV_DONTNEED);
	}
	return NULL;
}

int main(int argc, char *argv[])
{
	int num, i, ret, pid, status;
	int pids[MAXNUM];

	if (argc < 2)
		return 0;

	setpgid(0, 0);
	signal(SIGALRM, alarm_handler);
	num = atoi(argv[1]);
	pid = getpid();

	for (i = 0; i < num; ++i) {
		ret = fork();
		if (!ret) {
			worker(i, pid);
			exit(0);
		}
		pids[i] = ret;
	}
	sleep(1);
	kill(-pid, SIGALRM);
	sleep(60);
	for (i = 0; i < num; i++)
		kill(pids[i], SIGKILL);
	for (i = 0; i < num; i++)
		waitpid(pids[i], &status, 0);
	return 0;
}

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
Kirill A. Shutemov
6a6135b64f memcg: typo in comment to mem_cgroup_print_oom_info()
s/mem_cgroup_print_mem_info/mem_cgroup_print_oom_info/

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
Kirill A. Shutemov
2e72b6347c memcg: implement memory thresholds
It allows to register multiple memory and memsw thresholds and gets
notifications when it crosses.

To register a threshold application need:
- create an eventfd;
- open memory.usage_in_bytes or memory.memsw.usage_in_bytes;
- write string like "<event_fd> <memory.usage_in_bytes> <threshold>" to
  cgroup.event_control.

Application will be notified through eventfd when memory usage crosses
threshold in any direction.

It's applicable for root and non-root cgroup.

It uses stats to track memory usage, simmilar to soft limits. It checks
if we need to send event to userspace on every 100 page in/out. I guess
it's good compromise between performance and accuracy of thresholds.

[akpm@linux-foundation.org: coding-style fixes]
[nishimura@mxp.nes.nec.co.jp: fix documentation merge issue]
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
Kirill A. Shutemov
378ce724bc memcg: rework usage of stats by soft limit
Instead of incrementing counter on each page in/out and comparing it with
constant, we set counter to constant, decrement counter on each page
in/out and compare it with zero.  We want to make comparing as fast as
possible.  On many RISC systems (probably not only RISC) comparing with
zero is more effective than comparing with a constant, since not every
constant can be immediate operand for compare instruction.

Also, I've renamed MEM_CGROUP_STAT_EVENTS to MEM_CGROUP_STAT_SOFTLIMIT,
since really it's not a generic counter.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
Kirill A. Shutemov
104f39284e memcg: extract mem_group_usage() from mem_cgroup_read()
Helper to get memory or mem+swap usage of the cgroup.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
Daisuke Nishimura
483c30b514 memcg: improve performance in moving swap charge
Try to reduce overheads in moving swap charge by:

- Adds a new function(__mem_cgroup_put), which takes "count" as a arg and
  decrement mem->refcnt by "count".
- Removed res_counter_uncharge, css_put, and mem_cgroup_put from the path
  of moving swap account, and consolidate all of them into mem_cgroup_clear_mc.
  We cannot do that about mc.to->refcnt.

These changes reduces the overhead from 1.35sec to 0.9sec to move charges
of 1G anonymous memory(including 500MB swap) in my test environment.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Daisuke Nishimura
024914477e memcg: move charges of anonymous swap
This patch is another core part of this move-charge-at-task-migration
feature.  It enables moving charges of anonymous swaps.

To move the charge of swap, we need to exchange swap_cgroup's record.

In current implementation, swap_cgroup's record is protected by:

  - page lock: if the entry is on swap cache.
  - swap_lock: if the entry is not on swap cache.

This works well in usual swap-in/out activity.

But this behavior make the feature of moving swap charge check many
conditions to exchange swap_cgroup's record safely.

So I changed modification of swap_cgroup's recored(swap_cgroup_record())
to use xchg, and define a new function to cmpxchg swap_cgroup's record.

This patch also enables moving charge of non pte_present but not uncharged
swap caches, which can be exist on swap-out path, by getting the target
pages via find_get_page() as do_mincore() does.

[kosaki.motohiro@jp.fujitsu.com: fix ia64 build]
[akpm@linux-foundation.org: fix typos]
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Daisuke Nishimura
8033b97c9b memcg: avoid oom during moving charge
This move-charge-at-task-migration feature has extra charges on
"to"(pre-charges) and "from"(left-over charges) during moving charge.
This means unnecessary oom can happen.

This patch tries to avoid such oom.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Daisuke Nishimura
854ffa8d10 memcg: improve performance in moving charge
Try to reduce overheads in moving charge by:

- Instead of calling res_counter_uncharge() against the old cgroup in
  __mem_cgroup_move_account() everytime, call res_counter_uncharge() at the end
  of task migration once.
- removed css_get(&to->css) from __mem_cgroup_move_account() because callers
  should have already called css_get(). And removed css_put(&to->css) too,
  which was called by callers of move_account on success of move_account.
- Instead of calling __mem_cgroup_try_charge(), i.e. res_counter_charge(),
  repeatedly, call res_counter_charge(PAGE_SIZE * count) in can_attach() if
  possible.
- Instead of calling css_get()/css_put() repeatedly, make use of coalesce
  __css_get()/__css_put() if possible.

These changes reduces the overhead from 1.7sec to 0.6sec to move charges
of 1G anonymous memory in my test environment.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Daisuke Nishimura
4ffef5feff memcg: move charges of anonymous page
This patch is the core part of this move-charge-at-task-migration feature.
 It implements functions to move charges of anonymous pages mapped only by
the target task.

Implementation:
- define struct move_charge_struct and a valuable of it(mc) to remember the
  count of pre-charges and other information.
- At can_attach(), get anon_rss of the target mm, call __mem_cgroup_try_charge()
  repeatedly and count up mc.precharge.
- At attach(), parse the page table, find a target page to be move, and call
  mem_cgroup_move_account() about the page.
- Cancel all precharges if mc.precharge > 0 on failure or at the end of
  task move.

[akpm@linux-foundation.org: a little simplification]
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Daisuke Nishimura
7dc74be032 memcg: add interface to move charge at task migration
In current memcg, charges associated with a task aren't moved to the new
cgroup at task migration.  Some users feel this behavior to be strange.
These patches are for this feature, that is, for charging to the new
cgroup and, of course, uncharging from the old cgroup at task migration.

This patch adds "memory.move_charge_at_immigrate" file, which is a flag
file to determine whether charges should be moved to the new cgroup at
task migration or not and what type of charges should be moved.  This
patch also adds read and write handlers of the file.

This patch also adds no-op handlers for this feature.  These handlers will
be implemented in later patches.  And you cannot write any values other
than 0 to move_charge_at_immigrate yet.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Thiago Farina
648bcc7711 mm/memcontrol.c: fix "integer as NULL pointer" sparse warning
mm/memcontrol.c:2548:32: warning: Using plain integer as NULL pointer

Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:26 -08:00
Daisuke Nishimura
fce6647757 memcg: ensure list is empty at rmdir
Current mem_cgroup_force_empty() only ensures mem->res.usage == 0 on
success.  But this doesn't guarantee memcg's LRU is really empty, because
there are some cases in which !PageCgrupUsed pages exist on memcg's LRU.

For example:
- Pages can be uncharged by its owner process while they are on LRU.
- race between mem_cgroup_add_lru_list() and __mem_cgroup_uncharge_common().

So there can be a case in which the usage is zero but some of the LRUs are not empty.

OTOH, mem_cgroup_del_lru_list(), which can be called asynchronously with
rmdir, accesses the mem_cgroup, so this access can cause a problem if it
races with rmdir because the mem_cgroup might have been freed by rmdir.

Actually, I saw a bug which seems to be caused by this race.

	[1530745.949906] BUG: unable to handle kernel NULL pointer dereference at 0000000000000230
	[1530745.950651] IP: [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651] PGD 3863de067 PUD 3862c7067 PMD 0
	[1530745.950651] Oops: 0002 [#1] SMP
	[1530745.950651] last sysfs file: /sys/devices/system/cpu/cpu7/cache/index1/shared_cpu_map
	[1530745.950651] CPU 3
	[1530745.950651] Modules linked in: configs ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp nfsd nfs_acl auth_rpcgss exportfs autofs4 hidp rfcomm l2cap crc16 bluetooth lockd sunrpc ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp bnx2i cnic uio ipv6 cxgb3i cxgb3 mdio libiscsi_tcp libiscsi scsi_transport_iscsi dm_mirror dm_multipath scsi_dh video output sbs sbshc battery ac lp kvm_intel kvm sg ide_cd_mod cdrom serio_raw tpm_tis tpm tpm_bios acpi_memhotplug button parport_pc parport rtc_cmos rtc_core rtc_lib e1000 i2c_i801 i2c_core pcspkr dm_region_hash dm_log dm_mod ata_piix libata shpchp megaraid_mbox sd_mod scsi_mod megaraid_mm ext3 jbd uhci_hcd ohci_hcd ehci_hcd [last unloaded: freq_table]
	[1530745.950651] Pid: 19653, comm: shmem_test_02 Tainted: G   M       2.6.32-mm1-00701-g2b04386 #3 Express5800/140Rd-4 [N8100-1065]
	[1530745.950651] RIP: 0010:[<ffffffff810fbc11>]  [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651] RSP: 0018:ffff8803863ddcb8  EFLAGS: 00010002
	[1530745.950651] RAX: 00000000000001e0 RBX: ffff8803abc02238 RCX: 00000000000001e0
	[1530745.950651] RDX: 0000000000000000 RSI: ffff88038611a000 RDI: ffff8803abc02238
	[1530745.950651] RBP: ffff8803863ddcc8 R08: 0000000000000002 R09: ffff8803a04c8643
	[1530745.950651] R10: 0000000000000000 R11: ffffffff810c7333 R12: 0000000000000000
	[1530745.950651] R13: ffff880000017f00 R14: 0000000000000092 R15: ffff8800179d0310
	[1530745.950651] FS:  0000000000000000(0000) GS:ffff880017800000(0000) knlGS:0000000000000000
	[1530745.950651] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
	[1530745.950651] CR2: 0000000000000230 CR3: 0000000379d87000 CR4: 00000000000006e0
	[1530745.950651] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	[1530745.950651] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
	[1530745.950651] Process shmem_test_02 (pid: 19653, threadinfo ffff8803863dc000, task ffff88038612a8a0)
	[1530745.950651] Stack:
	[1530745.950651]  ffffea00040c2fe8 0000000000000000 ffff8803863ddd98 ffffffff810c739a
	[1530745.950651] <0> 00000000863ddd18 000000000000000c 0000000000000000 0000000000000000
	[1530745.950651] <0> 0000000000000002 0000000000000000 ffff8803863ddd68 0000000000000046
	[1530745.950651] Call Trace:
	[1530745.950651]  [<ffffffff810c739a>] release_pages+0x142/0x1e7
	[1530745.950651]  [<ffffffff810c778f>] ? pagevec_move_tail+0x6e/0x112
	[1530745.950651]  [<ffffffff810c781e>] pagevec_move_tail+0xfd/0x112
	[1530745.950651]  [<ffffffff810c78a9>] lru_add_drain+0x76/0x94
	[1530745.950651]  [<ffffffff810dba0c>] exit_mmap+0x6e/0x145
	[1530745.950651]  [<ffffffff8103f52d>] mmput+0x5e/0xcf
	[1530745.950651]  [<ffffffff81043ea8>] exit_mm+0x11c/0x129
	[1530745.950651]  [<ffffffff8108fb29>] ? audit_free+0x196/0x1c9
	[1530745.950651]  [<ffffffff81045353>] do_exit+0x1f5/0x6b7
	[1530745.950651]  [<ffffffff8106133f>] ? up_read+0x2b/0x2f
	[1530745.950651]  [<ffffffff8137d187>] ? lockdep_sys_exit_thunk+0x35/0x67
	[1530745.950651]  [<ffffffff81045898>] do_group_exit+0x83/0xb0
	[1530745.950651]  [<ffffffff810458dc>] sys_exit_group+0x17/0x1b
	[1530745.950651]  [<ffffffff81002c1b>] system_call_fastpath+0x16/0x1b
	[1530745.950651] Code: 54 53 0f 1f 44 00 00 83 3d cc 29 7c 00 00 41 89 f4 75 63 eb 4e 48 83 7b 08 00 75 04 0f 0b eb fe 48 89 df e8 18 f3 ff ff 44 89 e2 <48> ff 4c d0 50 48 8b 05 2b 2d 7c 00 48 39 43 08 74 39 48 8b 4b
	[1530745.950651] RIP  [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651]  RSP <ffff8803863ddcb8>
	[1530745.950651] CR2: 0000000000000230
	[1530745.950651] ---[ end trace c3419c1bb8acc34f ]---
	[1530745.950651] Fixing recursive fault but reboot is needed!

The problem here is pages on LRU may contain pointer to stale memcg.  To
make res->usage to be 0, all pages on memcg must be uncharged or moved to
another(parent) memcg.  Moved page_cgroup have already removed from
original LRU, but uncharged page_cgroup contains pointer to memcg withou
PCG_USED bit.  (This asynchronous LRU work is for improving performance.)
If PCG_USED bit is not set, page_cgroup will never be added to memcg's
LRU.  So, about pages not on LRU, they never access stale pointer.  Then,
what we have to take care of is page_cgroup _on_ LRU list.  This patch
fixes this problem by making mem_cgroup_force_empty() visit all LRUs
before exiting its loop and guarantee there are no pages on its LRU.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:39 -08:00
Linus Torvalds
d4220f987c Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (34 commits)
  HWPOISON: Remove stray phrase in a comment
  HWPOISON: Try to allocate migration page on the same node
  HWPOISON: Don't do early filtering if filter is disabled
  HWPOISON: Add a madvise() injector for soft page offlining
  HWPOISON: Add soft page offline support
  HWPOISON: Undefine short-hand macros after use to avoid namespace conflict
  HWPOISON: Use new shake_page in memory_failure
  HWPOISON: Use correct name for MADV_HWPOISON in documentation
  HWPOISON: mention HWPoison in Kconfig entry
  HWPOISON: Use get_user_page_fast in hwpoison madvise
  HWPOISON: add an interface to switch off/on all the page filters
  HWPOISON: add memory cgroup filter
  memcg: add accessor to mem_cgroup.css
  memcg: rename and export try_get_mem_cgroup_from_page()
  HWPOISON: add page flags filter
  mm: export stable page flags
  HWPOISON: limit hwpoison injector to known page types
  HWPOISON: add fs/device filters
  HWPOISON: return 0 to indicate success reliably
  HWPOISON: make semantics of IGNORED/DELAYED clear
  ...
2009-12-16 12:36:49 -08:00
Bob Liu
aa20d489ce memcg: code clean, remove unused variable in mem_cgroup_resize_limit()
Variable `progress' isn't used in mem_cgroup_resize_limit() any more.
Remove it.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:08 -08:00
Daisuke Nishimura
9ab322caa3 memcg: remove memcg_tasklist
memcg_tasklist was introduced at commit 7f4d454d(memcg: avoid deadlock
caused by race between oom and cpuset_attach) instead of cgroup_mutex to
fix a deadlock problem.  The cgroup_mutex, which was removed by the
commit, in mem_cgroup_out_of_memory() was originally introduced at commit
c7ba5c9e (Memory controller: OOM handling).

IIUC, the intention of this cgroup_mutex was to prevent task move during
select_bad_process() so that situations like below can be avoided.

  Assume cgroup "foo" has exceeded its limit and is about to trigger oom.
  1. Process A, which has been in cgroup "baa" and uses large memory, is just
     moved to cgroup "foo". Process A can be the candidates for being killed.
  2. Process B, which has been in cgroup "foo" and uses large memory, is just
     moved from cgroup "foo". Process B can be excluded from the candidates for
     being killed.

But these race window exists anyway even if we hold a lock, because
__mem_cgroup_try_charge() decides wether it should trigger oom or not
outside of the lock.  So the original cgroup_mutex in
mem_cgroup_out_of_memory and thus current memcg_tasklist has no use.  And
IMHO, those races are not so critical for users.

This patch removes it and make codes simpler.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura
d31f56dbf8 memcg: avoid oom-killing innocent task in case of use_hierarchy
task_in_mem_cgroup(), which is called by select_bad_process() to check
whether a task can be a candidate for being oom-killed from memcg's limit,
checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs
to).

But this check return true(it's false positive) when:

	<some path>/aa		use_hierarchy == 0	<- hitting limit
	  <some path>/aa/00	use_hierarchy == 1	<- the task belongs to

This leads to killing an innocent task in aa/00.  This patch is a fix for
this bug.  And this patch also fixes the arg for
mem_cgroup_print_oom_info().  We should print information of mem_cgroup
which the task being killed, not current, belongs to.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura
57f9fd7d25 memcg: cleanup mem_cgroup_move_parent()
mem_cgroup_move_parent() calls try_charge first and cancel_charge on
failure.  IMHO, charge/uncharge(especially charge) is high cost operation,
so we should avoid it as far as possible.

This patch tries to delay try_charge in mem_cgroup_move_parent() by
re-ordering checks it does.

And this patch renames mem_cgroup_move_account() to
__mem_cgroup_move_account(), changes the return value of
__mem_cgroup_move_account() from int to void, and adds a new
wrapper(mem_cgroup_move_account()), which checks whether a @pc is valid
for moving account and calls __mem_cgroup_move_account().

This patch removes the last caller of trylock_page_cgroup(), so removes
its definition too.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura
a3032a2c15 memcg: add mem_cgroup_cancel_charge()
There are some places calling both res_counter_uncharge() and css_put() to
cancel the charge and the refcnt we have got by mem_cgroup_tyr_charge().

This patch introduces mem_cgroup_cancel_charge() and call it in those
places.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
KAMEZAWA Hiroyuki
d8046582d5 memcg: make memcg's file mapped consistent with global VM
In global VM, FILE_MAPPED is used but memcg uses MAPPED_FILE.  This makes
grep difficult.  Replace memcg's MAPPED_FILE with FILE_MAPPED

And in global VM, mapped shared memory is accounted into FILE_MAPPED.
But memcg doesn't. fix it.
Note:
  page_is_file_cache() just checks SwapBacked or not.
  So, we need to check PageAnon.

Cc: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
KAMEZAWA Hiroyuki
cdec2e4265 memcg: coalesce charging via percpu storage
This is a patch for coalescing access to res_counter at charging by percpu
caching.  At charge, memcg charges 64pages and remember it in percpu
cache.  Because it's cache, drain/flush if necessary.

This version uses public percpu area.
 2 benefits for using public percpu area.
 1. Sum of stocked charge in the system is limited to # of cpus
    not to the number of memcg. This shows better synchonization.
 2. drain code for flush/cpuhotplug is very easy (and quick)

The most important point of this patch is that we never touch res_counter
in fast path. The res_counter is system-wide shared counter which is modified
very frequently. We shouldn't touch it as far as we can for avoiding
false sharing.

On x86-64 8cpu server, I tested overheads of memcg at page fault by
running a program which does map/fault/unmap in a loop. Running
a task per a cpu by taskset and see sum of the number of page faults
in 60secs.

[without memcg config]
  40156968  page-faults              #      0.085 M/sec   ( +-   0.046% )
  27.67 cache-miss/faults

[root cgroup]
  36659599  page-faults              #      0.077 M/sec   ( +-   0.247% )
  31.58 cache miss/faults

[in a child cgroup]
  18444157  page-faults              #      0.039 M/sec   ( +-   0.133% )
  69.96 cache miss/faults

[ + coalescing uncharge patch]
  27133719  page-faults              #      0.057 M/sec   ( +-   0.155% )
  47.16 cache miss/faults

[ + coalescing uncharge patch + this patch ]
  34224709  page-faults              #      0.072 M/sec   ( +-   0.173% )
  34.69 cache miss/faults

Changelog (since Oct/2):
  - updated comments
  - replaced get_cpu_var() with __get_cpu_var() if possible.
  - removed mutex for system-wide drain. adds a counter instead of it.
  - removed CONFIG_HOTPLUG_CPU

Changelog (old):
  - rebased onto the latest mmotm
  - moved charge size check before __GFP_WAIT check for avoiding unnecesary
  - added asynchronous flush routine.
  - fixed bugs pointed out by Nishimura-san.

[akpm@linux-foundation.org: tweak comments]
[nishimura@mxp.nes.nec.co.jp: don't do INIT_WORK() repeatedly against the same work_struct]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
KAMEZAWA Hiroyuki
569b846df5 memcg: coalesce uncharge during unmap/truncate
In massive parallel enviroment, res_counter can be a performance
bottleneck.  One strong techinque to reduce lock contention is reducing
calls by coalescing some amount of calls into one.

Considering charge/uncharge chatacteristic,
	- charge is done one by one via demand-paging.
	- uncharge is done by
		- in chunk at munmap, truncate, exit, execve...
		- one by one via vmscan/paging.

It seems we have a chance to coalesce uncharges for improving scalability
at unmap/truncation.

This patch is a for coalescing uncharge.  For avoiding scattering memcg's
structure to functions under /mm, this patch adds memcg batch uncharge
information to the task.  A reason for per-task batching is for making use
of caller's context information.  We do batched uncharge (deleyed
uncharge) when truncation/unmap occurs but do direct uncharge when
uncharge is called by memory reclaim (vmscan.c).

The degree of coalescing depends on callers
  - at invalidate/trucate... pagevec size
  - at unmap ....ZAP_BLOCK_SIZE
(memory itself will be freed in this degree.)
Then, we'll not coalescing too much.

On x86-64 8cpu server, I tested overheads of memcg at page fault by
running a program which does map/fault/unmap in a loop. Running
a task per a cpu by taskset and see sum of the number of page faults
in 60secs.

[without memcg config]
  40156968  page-faults              #      0.085 M/sec   ( +-   0.046% )
  27.67 cache-miss/faults
[root cgroup]
  36659599  page-faults              #      0.077 M/sec   ( +-   0.247% )
  31.58 miss/faults
[in a child cgroup]
  18444157  page-faults              #      0.039 M/sec   ( +-   0.133% )
  69.96 miss/faults
[child with this patch]
  27133719  page-faults              #      0.057 M/sec   ( +-   0.155% )
  47.16 miss/faults

We can see some amounts of improvement.
(root cgroup doesn't affected by this patch)
Another patch for "charge" will follow this and above will be improved more.

Changelog(since 2009/10/02):
 - renamed filed of memcg_batch (as pages to bytes, memsw to memsw_bytes)
 - some clean up and commentary/description updates.
 - added initialize code to copy_process(). (possible bug fix)

Changelog(old):
 - fixed !CONFIG_MEM_CGROUP case.
 - rebased onto the latest mmotm + softlimit fix patches.
 - unified patch for callers
 - added commetns.
 - make ->do_batch as bool.
 - removed css_get() at el. We don't need it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Kirill A. Shutemov
cd9b45b78a memcg: fix memory.memsw.usage_in_bytes for root cgroup
A memory cgroup has a memory.memsw.usage_in_bytes file.  It shows the sum
of the usage of pages and swapents in the cgroup.  Presently the root
cgroup's memsw.usage_in_bytes shows the wrong value - the number of
swapents are not added.

So take MEM_CGROUP_STAT_SWAPOUT into account.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Wu Fengguang
d324236b33 memcg: add accessor to mem_cgroup.css
So that an outside user can free the reference count grabbed by
try_get_mem_cgroup_from_page().

CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Hugh Dickins <hugh.dickins@tiscali.co.uk>
CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
CC: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16 12:19:59 +01:00
Wu Fengguang
e42d9d5d47 memcg: rename and export try_get_mem_cgroup_from_page()
So that the hwpoison injector can get mem_cgroup for arbitrary page
and thus know whether it is owned by some mem_cgroup task(s).

[AK: Merged with latest git tree]

CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Hugh Dickins <hugh.dickins@tiscali.co.uk>
CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
CC: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16 12:19:59 +01:00
Hugh Dickins
407f9c8b08 ksm: mem cgroup charge swapin copy
But ksm swapping does require one small change in mem cgroup handling.
When do_swap_page()'s call to ksm_might_need_to_copy() does indeed
substitute a duplicate page to accommodate a different anon_vma (or a the
!PageSwapCache check in mem_cgroup_try_charge_swapin().

That was returning success without charging, on the assumption that
pte_same() would fail after, which is not the case here.  Originally I
proposed that success, so that an unshrinkable mem cgroup at its limit
would not fail unnecessarily; but that's a minor point, and there are
plenty of other places where we may fail an overallocation which might
later prove unnecessary.  So just go ahead and do what all the other
exceptions do: proceed to charge current mm.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:19 -08:00
André Goddard Rosa
af901ca181 tree-wide: fix assorted typos all over the place
That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:55 +01:00
Uwe Kleine-Knig
21ae2956ce tree-wide: fix typos "aquire" -> "acquire", "cumsumed" -> "consumed"
This patch was generated by

	git grep -E -i -l '[Aa]quire' | xargs -r perl -p -i -e 's/([Aa])quire/$1cquire/'

and the cumsumed was found by checking the diff for aquire.

Signed-off-by: Uwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-11-09 09:40:57 +01:00
KAMEZAWA Hiroyuki
ef8745c1e7 memcg: reduce check for softlimit excess
In charge/uncharge/reclaim path, usage_in_excess is calculated repeatedly
and it takes res_counter's spin_lock every time.

This patch removes unnecessary calls for res_count_soft_limit_excess.

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:13 -07:00
KAMEZAWA Hiroyuki
4e649152cb memcg: some modification to softlimit under hierarchical memory reclaim.
This patch clean up/fixes for memcg's uncharge soft limit path.

Problems:
  Now, res_counter_charge()/uncharge() handles softlimit information at
  charge/uncharge and softlimit-check is done when event counter per memcg
  goes over limit. Now, event counter per memcg is updated only when
  memory usage is over soft limit. Here, considering hierarchical memcg
  management, ancesotors should be taken care of.

  Now, ancerstors(hierarchy) are handled in charge() but not in uncharge().
  This is not good.

  Prolems:
  1. memcg's event counter incremented only when softlimit hits. That's bad.
     It makes event counter hard to be reused for other purpose.

  2. At uncharge, only the lowest level rescounter is handled. This is bug.
     Because ancesotor's event counter is not incremented, children should
     take care of them.

  3. res_counter_uncharge()'s 3rd argument is NULL in most case.
     ops under res_counter->lock should be small. No "if" sentense is better.

Fixes:
  * Removed soft_limit_xx poitner and checks in charge and uncharge.
    Do-check-only-when-necessary scheme works enough well without them.

  * make event-counter of memcg incremented at every charge/uncharge.
    (per-cpu area will be accessed soon anyway)

  * All ancestors are checked at soft-limit-check. This is necessary because
    ancesotor's event counter may never be modified. Then, they should be
    checked at the same time.

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:13 -07:00
KAMEZAWA Hiroyuki
26251eaf98 memcg: fix refcnt going negative
__mem_cgroup_largest_soft_limit_node() returns a mem_cgroup_per_zone "mz"
with incremnted mz->mem->css's refcnt.  Then, the caller of this function
has to call css_put(mz->mem->css).

But, mz can be !NULL even if "not found" i.e.  without css_get().  By
this, css->refcnt will go down to minus.

This may cause various things...one of results will be
initite-loop in css_tryget()  as this.

INFO: RCU detected CPU 0 stall (t=10000 jiffies)
sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU 0:
<snip>

 <<EOE>>  <IRQ>  [<ffffffff810884bd>] trace_hardirqs_off+0xd/0x10
  [<ffffffff8102a940>] flat_send_IPI_mask+0x90/0xb0
  [<ffffffff8102a9c9>] flat_send_IPI_all+0x69/0x70
  [<ffffffff81027372>] arch_trigger_all_cpu_backtrace+0x62/0xa0
  [<ffffffff810bff8e>] __rcu_pending+0x7e/0x370
  [<ffffffff810c02c7>] rcu_check_callbacks+0x47/0x130
  [<ffffffff81063a26>] update_process_times+0x46/0x70
  [<ffffffff81085930>] tick_sched_timer+0x60/0x160
  [<ffffffff810858d0>] ? tick_sched_timer+0x0/0x160
  [<ffffffff8107a03a>] __run_hrtimer+0xba/0x150
  [<ffffffff8107a325>] hrtimer_interrupt+0xd5/0x1b0
  [<ffffffff81426dfe>] ? trace_hardirqs_off_thunk+0x3a/0x3c
  [<ffffffff8142cacd>] smp_apic_timer_interrupt+0x6d/0x9b
  [<ffffffff8100cb33>] apic_timer_interrupt+0x13/0x20
  <EOI>  [<ffffffff811317b6>] ? mem_cgroup_walk_tree+0x156/0x180
  [<ffffffff811316d3>] ? mem_cgroup_walk_tree+0x73/0x180
  [<ffffffff81131692>] ? mem_cgroup_walk_tree+0x32/0x180
  [<ffffffff81131a00>] ? mem_cgroup_get_local_stat+0x0/0x110
  [<ffffffff81131d5b>] ? mem_control_stat_show+0x14b/0x330
  [<ffffffff810a57fd>] ? cgroup_seqfile_show+0x3d/0x60

Above shows CPU0 caught in css_tryget()'s inifinite loop because
of bad refcnt.

This is a fix to set mz=NULL at the top of retry path.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:12 -07:00
Daisuke Nishimura
1dd3a27326 memcg: show swap usage in stat file
We now count MEM_CGROUP_STAT_SWAPOUT, so we can show swap usage.  It would
be useful for users to show swap usage in memory.stat file, because they
don't need calculate memsw.usage - res.usage to know swap usage.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh
0c3e73e84f memcg: improve resource counter scalability
Reduce the resource counter overhead (mostly spinlock) associated with the
root cgroup.  This is a part of the several patches to reduce mem cgroup
overhead.  I had posted other approaches earlier (including using percpu
counters).  Those patches will be a natural addition and will be added
iteratively on top of these.

The patch stops resource counter accounting for the root cgroup.  The data
for display is derived from the statisitcs we maintain via
mem_cgroup_charge_statistics (which is more scalable).  What happens today
is that, we do double accounting, once using res_counter_charge() and once
using memory_cgroup_charge_statistics().  For the root, since we don't
implement limits any more, we don't need to track every charge via
res_counter_charge() and check for limit being exceeded and reclaim.

The main mem->res usage_in_bytes can be derived by summing the cache and
rss usage data from memory statistics (MEM_CGROUP_STAT_RSS and
MEM_CGROUP_STAT_CACHE).  However, for memsw->res usage_in_bytes, we need
additional data about swapped out memory.  This patch adds a
MEM_CGROUP_STAT_SWAPOUT and uses that along with MEM_CGROUP_STAT_RSS and
MEM_CGROUP_STAT_CACHE to derive the memsw data.  This data is computed
recursively when hierarchy is enabled.

The tests results I see on a 24 way show that

1. The lock contention disappears from /proc/lock_stats
2. The results of the test are comparable to running with
   cgroup_disable=memory.

Here is a sample of my program runs

Without Patch

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7192804.124144  task-clock-msecs         #     23.937 CPUs
         424691  context-switches         #      0.000 M/sec
            267  CPU-migrations           #      0.000 M/sec
       28498113  page-faults              #      0.004 M/sec
  5826093739340  cycles                   #    809.989 M/sec
   408883496292  instructions             #      0.070 IPC
     7057079452  cache-references         #      0.981 M/sec
     3036086243  cache-misses             #      0.422 M/sec

  300.485365680  seconds time elapsed

With cgroup_disable=memory

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7182183.546587  task-clock-msecs         #     23.915 CPUs
         425458  context-switches         #      0.000 M/sec
            203  CPU-migrations           #      0.000 M/sec
       92545093  page-faults              #      0.013 M/sec
  6034363609986  cycles                   #    840.185 M/sec
   437204346785  instructions             #      0.072 IPC
     6636073192  cache-references         #      0.924 M/sec
     2358117732  cache-misses             #      0.328 M/sec

  300.320905827  seconds time elapsed

With this patch applied

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7191619.223977  task-clock-msecs         #     23.955 CPUs
         422579  context-switches         #      0.000 M/sec
             88  CPU-migrations           #      0.000 M/sec
       91946060  page-faults              #      0.013 M/sec
  5957054385619  cycles                   #    828.333 M/sec
  1058117350365  instructions             #      0.178 IPC
     9161776218  cache-references         #      1.274 M/sec
     1920494280  cache-misses             #      0.267 M/sec

  300.218764862  seconds time elapsed

Data from Prarit (kernel compile with make -j64 on a 64
CPU/32G machine)

For a single run

Without patch

real 27m8.988s
user 87m24.916s
sys 382m6.037s

With patch

real    4m18.607s
user    84m58.943s
sys     50m52.682s

With config turned off

real    4m54.972s
user    90m13.456s
sys     50m19.711s

NOTE: The data looks counterintuitive due to the increased performance
with the patch, even over the config being turned off. We probably need
more runs, but so far all testing has shown that the patches definitely
help.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh
4e41695356 memory controller: soft limit reclaim on contention
Implement reclaim from groups over their soft limit

Permit reclaim from memory cgroups on contention (via the direct reclaim
path).

memory cgroup soft limit reclaim finds the group that exceeds its soft
limit by the largest number of pages and reclaims pages from it and then
reinserts the cgroup into its correct place in the rbtree.

Add additional checks to mem_cgroup_hierarchical_reclaim() to detect long
loops in case all swap is turned off.  The code has been refactored and
the loop check (loop < 2) has been enhanced for soft limits.  For soft
limits, we try to do more targetted reclaim.  Instead of bailing out after
two loops, the routine now reclaims memory proportional to the size by
which the soft limit is exceeded.  The proportion has been empirically
determined.

[akpm@linux-foundation.org: build fix]
[kamezawa.hiroyu@jp.fujitsu.com: fix softlimit css refcnt handling]
[nishimura@mxp.nes.nec.co.jp: refcount of the "victim" should be decremented before exiting the loop]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh
75822b4495 memory controller: soft limit refactor reclaim flags
Refactor mem_cgroup_hierarchical_reclaim()

Refactor the arguments passed to mem_cgroup_hierarchical_reclaim() into
flags, so that new parameters don't have to be passed as we make the
reclaim routine more flexible

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh
f64c3f5494 memory controller: soft limit organize cgroups
Organize cgroups over soft limit in a RB-Tree

Introduce an RB-Tree for storing memory cgroups that are over their soft
limit.  The overall goal is to

1. Add a memory cgroup to the RB-Tree when the soft limit is exceeded.
   We are careful about updates, updates take place only after a particular
   time interval has passed
2. We remove the node from the RB-Tree when the usage goes below the soft
   limit

The next set of patches will exploit the RB-Tree to get the group that is
over its soft limit by the largest amount and reclaim from it, when we
face memory contention.

[hugh.dickins@tiscali.co.uk: CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y fails to boot]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh
296c81d89f memory controller: soft limit interface
Add an interface to allow get/set of soft limits.  Soft limits for memory
plus swap controller (memsw) is currently not supported.  Resource
counters have been enhanced to support soft limits and new type
RES_SOFT_LIMIT has been added.  Unlike hard limits, soft limits can be
directly set and do not need any reclaim or checks before setting them to
a newer value.

Kamezawa-San raised a question as to whether soft limit should belong to
res_counter.  Since all resources understand the basic concepts of hard
and soft limits, it is justified to add soft limits here.  Soft limits are
a generic resource usage feature, even file system quotas support soft
limits.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
KAMEZAWA Hiroyuki
261fb61a8b memcg: add comments explaining memory barriers
Add comments for the reason of smp_wmb() in mem_cgroup_commit_charge().

[akpm@linux-foundation.org: coding-style fixes]
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:58 -07:00
Balbir Singh
4b3bde4c98 memcg: remove the overhead associated with the root cgroup
Change the memory cgroup to remove the overhead associated with accounting
all pages in the root cgroup.  As a side-effect, we can no longer set a
memory hard limit in the root cgroup.

A new flag to track whether the page has been accounted or not has been
added as well.  Flags are now set atomically for page_cgroup,
pcg_default_flags is now obsolete and removed.

[akpm@linux-foundation.org: fix a few documentation glitches]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:58 -07:00
Ben Blum
be367d0992 cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc.  (This is a
pre-patch to cgroup-procs-writable.patch.)

Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader.  No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.

[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:58 -07:00
Johannes Weiner
b7c46d151c mm: drop unneeded double negations
Remove double negations where the operand is already boolean.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
KAMEZAWA Hiroyuki
887032670d cgroup avoid permanent sleep at rmdir
After commit ec64f51545 ("cgroup: fix
frequent -EBUSY at rmdir"), cgroup's rmdir (especially against memcg)
doesn't return -EBUSY by temporary ref counts.  That commit expects all
refs after pre_destroy() is temporary but...it wasn't.  Then, rmdir can
wait permanently.  This patch tries to fix that and change followings.

 - set CGRP_WAIT_ON_RMDIR flag before pre_destroy().
 - clear CGRP_WAIT_ON_RMDIR flag when the subsys finds racy case.
   if there are sleeping ones, wakes them up.
 - rmdir() sleeps only when CGRP_WAIT_ON_RMDIR flag is set.

Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Paul Menage <menage@google.com>
Acked-by: Balbir Sigh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-29 19:10:35 -07:00
Jens Axboe
8aa7e847d8 Fix congestion_wait() sync/async vs read/write confusion
Commit 1faa16d228 accidentally broke
the bdi congestion wait queue logic, causing us to wait on congestion
for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:53 +02:00
KAMEZAWA Hiroyuki
2ffebca6aa memcg: fix lru rotation in isolate_pages
Try to fix memcg's lru rotation sanity: make memcg use the same logic as
the global LRU does.

Now, at __isolate_lru_page() retruns -EBUSY, the page is rotated to the
tail of LRU in global LRU's isolate LRU pages.  But in memcg, it's not
handled.  This makes memcg do the same behavior as global LRU and rotate
LRU in the page is busy.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:48 -07:00
KAMEZAWA Hiroyuki
22a668d7c3 memcg: fix behavior under memory.limit equals to memsw.limit
A user can set memcg.limit_in_bytes == memcg.memsw.limit_in_bytes when the
user just want to limit the total size of applications, in other words,
not very interested in memory usage itself.  In this case, swap-out will
be done only by global-LRU.

But, under current implementation, memory.limit_in_bytes is checked at
first and try_to_free_page() may do swap-out.  But, that swap-out is
useless for memsw.limit_in_bytes and the thread may hit limit again.

This patch tries to fix the current behavior at memory.limit ==
memsw.limit case.  And documentation is updated to explain the behavior of
this special case.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:48 -07:00
KAMEZAWA Hiroyuki
8a9478ca7f memcg: fix swap accounting
This patch fixes mis-accounting of swap usage in memcg.

In the current implementation, memcg's swap account is uncharged only when
swap is completely freed.  But there are several cases where swap cannot
be freed cleanly.  For handling that, this patch changes that memcg
uncharges swap account when swap has no references other than cache.

By this, memcg's swap entry accounting can be fully synchronous with the
application's behavior.

This patch also changes memcg's hooks for swap-out.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:47 -07:00
Li Zefan
338c843108 memcg: remove some redundant checks
We don't need to check do_swap_account in the case that the function which
checks do_swap_account will never get called if do_swap_account == 0.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:47 -07:00
Balbir Singh
d69b042f3d memcg: add file-based RSS accounting
Add file RSS tracking per memory cgroup

We currently don't track file RSS, the RSS we report is actually anon RSS.
 All the file mapped pages, come in through the page cache and get
accounted there.  This patch adds support for accounting file RSS pages.
It should

1. Help improve the metrics reported by the memory resource controller
2. Will form the basis for a future shared memory accounting heuristic
   that has been proposed by Kamezawa.

Unfortunately, we cannot rename the existing "rss" keyword used in
memory.stat to "anon_rss".  We however, add "mapped_file" data and hope to
educate the end user through documentation.

[hugh.dickins@tiscali.co.uk: fix mem_cgroup_update_mapped_file_stat oops]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:47 -07:00
Rik van Riel
56e49d2188 vmscan: evict use-once pages first
When the file LRU lists are dominated by streaming IO pages, evict those
pages first, before considering evicting other pages.

This should be safe from deadlocks or performance problems
because only three things can happen to an inactive file page:

1) referenced twice and promoted to the active list
2) evicted by the pageout code
3) under IO, after which it will get evicted or promoted

The pages freed in this way can either be reused for streaming IO, or
allocated for something else.  If the pages are used for streaming IO,
this pageout pattern continues.  Otherwise, we will fall back to the
normal pageout pattern.

Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Elladan <elladan@eskimo.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:38 -07:00
Nikanth Karthikesan
46f7e602fb memcg: fix build warning and avoid checking for mem != null again and again
Fix build warning, "mem_cgroup_is_obsolete defined but not used" when
CONFIG_DEBUG_VM is not set.  Also avoid checking for !mem again and again.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-29 08:40:03 -07:00
Daisuke Nishimura
e767e0561d memcg: fix deadlock between lock_page_cgroup and mapping tree_lock
mapping->tree_lock can be acquired from interrupt context.  Then,
following dead lock can occur.

Assume "A" as a page.

 CPU0:
       lock_page_cgroup(A)
		interrupted
			-> take mapping->tree_lock.
 CPU1:
       take mapping->tree_lock
		-> lock_page_cgroup(A)

This patch tries to fix above deadlock by moving memcg's hook to out of
mapping->tree_lock.  charge/uncharge of pagecache/swapcache is protected
by page lock, not tree_lock.

After this patch, lock_page_cgroup() is not called under mapping->tree_lock.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-29 08:40:02 -07:00
Daisuke Nishimura
ae3abae64f memcg: fix mem_cgroup_shrink_usage()
Current mem_cgroup_shrink_usage() has two problems.

1. It doesn't call mem_cgroup_out_of_memory and doesn't update
   last_oom_jiffies, so pagefault_out_of_memory invokes global OOM.

2. Considering hierarchy, shrinking has to be done from the
   mem_over_limit, not from the memcg which the page would be charged to.

mem_cgroup_try_charge_swapin() does all of these things properly, so we
use it and call cancel_charge_swapin when it succeeded.

The name of "shrink_usage" is not appropriate for this behavior, so we
change it too.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
2009-05-02 15:36:09 -07:00
Daisuke Nishimura
c0bd3f63ce memcg: fix try_get_mem_cgroup_from_swapcache()
This is a bugfix for commit 3c776e6466
("memcg: charge swapcache to proper memcg").

Used bit of swapcache is solid under page lock, but considering
move_account, pc->mem_cgroup is not.

We need lock_page_cgroup() anyway.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-02 15:36:09 -07:00
KAMEZAWA Hiroyuki
a8031cb00e memcg: remove warning when CONFIG_DEBUG_VM=n
mm/memcontrol.c:318: warning: `mem_cgroup_is_obsolete' defined but not used

[akpm@linux-foundation.org: simplify as suggested by Balbir]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-13 15:04:32 -07:00
Daisuke Nishimura
83aae4c737 memcg: cleanup cache_charge
Current mem_cgroup_cache_charge is a bit complicated especially
in the case of shmem's swap-in.

This patch cleans it up by using try_charge_swapin and commit_charge_swapin.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:56 -07:00