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| author | David Rientjes <rientjes@google.com> | 2011-10-31 17:07:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-31 17:30:45 -0700 |
| commit | 7b0d44fa49b1dcfdcf4897f12ddd12ddeab1a9d7 (patch) | |
| tree | c840608f5266e4ba783f4c4405efe89b69ae5754 /mm/oom_kill.c | |
| parent | f660daac474c6f7c2d710100e29b3276a6f4db0a (diff) | |
| download | linux-7b0d44fa49b1dcfdcf4897f12ddd12ddeab1a9d7.tar.gz linux-7b0d44fa49b1dcfdcf4897f12ddd12ddeab1a9d7.tar.xz | |
oom: avoid killing kthreads if they assume the oom killed thread's mm
After selecting a task to kill, the oom killer iterates all processes and
kills all other threads that share the same mm_struct in different thread
groups. It would not otherwise be helpful to kill a thread if its memory
would not be subsequently freed.
A kernel thread, however, may assume a user thread's mm by using
use_mm(). This is only temporary and should not result in sending a
SIGKILL to that kthread.
This patch ensures that only user threads and not kthreads are sent a
SIGKILL if they share the same mm_struct as the oom killed task.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
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>
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index d897262068e2..b0d8943bc9fd 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -439,7 +439,7 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) task_unlock(p); /* - * Kill all processes sharing p->mm in other thread groups, if any. + * Kill all user processes sharing p->mm in other thread groups, if any. * They don't get access to memory reserves or a higher scheduler * priority, though, to avoid depletion of all memory or task * starvation. This prevents mm->mmap_sem livelock when an oom killed @@ -449,7 +449,8 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) * signal. */ for_each_process(q) - if (q->mm == mm && !same_thread_group(q, p)) { + if (q->mm == mm && !same_thread_group(q, p) && + !(q->flags & PF_KTHREAD)) { task_lock(q); /* Protect ->comm from prctl() */ pr_err("Kill process %d (%s) sharing same memory\n", task_pid_nr(q), q->comm); |