linux-toradex.git/mm/oom_kill.c, branch v3.4.40

signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()

2012-03-23T23:58:41+00:00

Change oom_kill_task() to use do_send_sig_info(SEND_SIG_FORCED) instead
of force_sig(SIGKILL).  With the recent changes we do not need force_ to
kill the CLONE_NEWPID tasks.

And this is more correct.  force_sig() can race with the exiting thread
even if oom_kill_task() checks p->mm != NULL, while
do_send_sig_info(group => true) kille the whole process.

Signed-off-by: Oleg Nesterov 
Cc: Tejun Heo 
Cc: Anton Vorontsov 
Cc: "Eric W. Biederman" 
Cc: KOSAKI Motohiro 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, memcg: pass charge order to oom killer

2012-03-22T00:54:59+00:00

The oom killer typically displays the allocation order at the time of oom
as a part of its diangostic messages (for global, cpuset, and mempolicy
ooms).

The memory controller may also pass the charge order to the oom killer so
it can emit the same information.  This is useful in determining how large
the memory allocation is that triggered the oom killer.

Signed-off-by: David Rientjes 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, oom: force oom kill on sysrq+f

2012-03-22T00:54:58+00:00

The oom killer chooses not to kill a thread if:

 - an eligible thread has already been oom killed and has yet to exit,
   and

 - an eligible thread is exiting but has yet to free all its memory and
   is not the thread attempting to currently allocate memory.

SysRq+F manually invokes the global oom killer to kill a memory-hogging
task.  This is normally done as a last resort to free memory when no
progress is being made or to test the oom killer itself.

For both uses, we always want to kill a thread and never defer.  This
patch causes SysRq+F to always kill an eligible thread and can be used to
force a kill even if another oom killed thread has failed to exit.

Signed-off-by: David Rientjes 
Acked-by: KOSAKI Motohiro 
Acked-by: Pekka Enberg 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, oom: introduce independent oom killer ratelimit state

2012-03-22T00:54:55+00:00

printk_ratelimit() uses the global ratelimit state for all printks.  The
oom killer should not be subjected to this state just because another
subsystem or driver may be flooding the kernel log.

This patch introduces printk ratelimiting specifically for the oom killer.

Signed-off-by: David Rientjes 
Acked-by: KOSAKI Motohiro 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, oom: do not emit oom killer warning if chosen thread is already exiting

2012-03-22T00:54:55+00:00

If a thread is chosen for oom kill and is already PF_EXITING, then the oom
killer simply sets TIF_MEMDIE and returns.  This allows the thread to have
access to memory reserves so that it may quickly exit.  This logic is
preceeded with a comment saying there's no need to alarm the sysadmin.
This patch adds truth to that statement.

There's no need to emit any warning about the oom condition if the thread
is already exiting since it will not be killed.  In this condition, just
silently return the oom killer since its only giving access to memory
reserves and is otherwise a no-op.

Acked-by: KOSAKI Motohiro 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: David Rientjes 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, oom: fold oom_kill_task() into oom_kill_process()

2012-03-22T00:54:55+00:00

oom_kill_task() has a single caller, so fold it into its parent function,
oom_kill_process().  Slightly reduces the number of lines in the oom
killer.

Acked-by: KOSAKI Motohiro 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: David Rientjes 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, oom: avoid looping when chosen thread detaches its mm

2012-03-22T00:54:55+00:00

oom_kill_task() returns non-zero iff the chosen process does not have any
threads with an attached ->mm.

In such a case, it's better to just return to the page allocator and retry
the allocation because memory could have been freed in the interim and the
oom condition may no longer exist.  It's unnecessary to loop in the oom
killer and find another thread to kill.

This allows both oom_kill_task() and oom_kill_process() to be converted to
void functions.  If the oom condition persists, the oom killer will be
recalled.

Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: David Rientjes 
Cc: KOSAKI Motohiro 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: unify remaining mem_cont, mem, etc. variable names to memcg

2012-01-13T04:13:06+00:00

Signed-off-by: Johannes Weiner 
Acked-by: David Rientjes 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Michal Hocko 
Cc: Balbir Singh 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: oom_kill: remove memcg argument from oom_kill_task()

2012-01-13T04:13:06+00:00

The memcg argument of oom_kill_task() hasn't been used since 341aea2
'oom-kill: remove boost_dying_task_prio()'.  Kill it.

Signed-off-by: Johannes Weiner 
Acked-by: David Rientjes 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Michal Hocko 
Cc: Balbir Singh 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracepoint: add tracepoints for debugging oom_score_adj

2012-01-11T00:30:44+00:00

oom_score_adj is used for guarding processes from OOM-Killer.  One of
problem is that it's inherited at fork().  When a daemon set oom_score_adj
and make children, it's hard to know where the value is set.

This patch adds some tracepoints useful for debugging. This patch adds
3 trace points.
  - creating new task
  - renaming a task (exec)
  - set oom_score_adj

To debug, users need to enable some trace pointer. Maybe filtering is useful as

# EVENT=/sys/kernel/debug/tracing/events/task/
# echo "oom_score_adj != 0" > $EVENT/task_newtask/filter
# echo "oom_score_adj != 0" > $EVENT/task_rename/filter
# echo 1 > $EVENT/enable
# EVENT=/sys/kernel/debug/tracing/events/oom/
# echo 1 > $EVENT/enable

output will be like this.
# grep oom /sys/kernel/debug/tracing/trace
bash-7699  [007] d..3  5140.744510: oom_score_adj_update: pid=7699 comm=bash oom_score_adj=-1000
bash-7699  [007] ...1  5151.818022: task_newtask: pid=7729 comm=bash clone_flags=1200011 oom_score_adj=-1000
ls-7729  [003] ...2  5151.818504: task_rename: pid=7729 oldcomm=bash newcomm=ls oom_score_adj=-1000
bash-7699  [002] ...1  5175.701468: task_newtask: pid=7730 comm=bash clone_flags=1200011 oom_score_adj=-1000
grep-7730  [007] ...2  5175.701993: task_rename: pid=7730 oldcomm=bash newcomm=grep oom_score_adj=-1000

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: KOSAKI Motohiro 
Acked-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds