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authorDavid Rientjes <rientjes@google.com>2010-10-26 14:21:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-26 16:52:05 -0700
commite18641e19a9204f241f04a5ac700168dcd18de4f (patch)
treef1058203588bd31584d217a25fabe4f7085a1f44 /mm
parent3d5992d2ac7dc09aed8ab537cba074589f0f0a52 (diff)
downloadvexpress-lsk-e18641e19a9204f241f04a5ac700168dcd18de4f.tar.gz
oom: avoid killing a task if a thread sharing its mm cannot be killed
The oom killer's goal is to kill a memory-hogging task so that it may exit, free its memory, and allow the current context to allocate the memory that triggered it in the first place. Thus, killing a task is pointless if other threads sharing its mm cannot be killed because of its /proc/pid/oom_adj or /proc/pid/oom_score_adj value. This patch checks whether any other thread sharing p->mm has an oom_score_adj of OOM_SCORE_ADJ_MIN. If so, the thread cannot be killed and oom_badness(p) returns 0, meaning it's unkillable. Signed-off-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/oom_kill.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 4029583a102..4395f371bc7 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -162,10 +162,11 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
return 0;
/*
- * Shortcut check for OOM_SCORE_ADJ_MIN so the entire heuristic doesn't
- * need to be executed for something that cannot be killed.
+ * Shortcut check for a thread sharing p->mm that is OOM_SCORE_ADJ_MIN
+ * so the entire heuristic doesn't need to be executed for something
+ * that cannot be killed.
*/
- if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
+ if (atomic_read(&p->mm->oom_disable_count)) {
task_unlock(p);
return 0;
}
@@ -680,7 +681,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
read_lock(&tasklist_lock);
if (sysctl_oom_kill_allocating_task &&
!oom_unkillable_task(current, NULL, nodemask) &&
- (current->signal->oom_adj != OOM_DISABLE)) {
+ current->mm && !atomic_read(&current->mm->oom_disable_count)) {
/*
* oom_kill_process() needs tasklist_lock held. If it returns
* non-zero, current could not be killed so we must fallback to