On Tue, 13 Dec 2011 16:59:32 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote: > The oom killer relies on logic that identifies threads that have already > been oom killed when scanning the tasklist and, if found, deferring until > such threads have exited. This is done by checking for any candidate > threads that have the TIF_MEMDIE bit set. > > For memcg ooms, candidate threads are first found by calling > task_in_mem_cgroup() since the oom killer should not defer if there's an > oom killed thread in another memcg. > > Unfortunately, task_in_mem_cgroup() excludes threads if they have > detached their mm in the process of exiting so TIF_MEMDIE is never > detected for such conditions. This is different for global, mempolicy, > and cpuset oom conditions where a detached mm is only excluded after > checking for TIF_MEMDIE and deferring, if necessary, in > select_bad_process(). > > The fix is to return true if a task has a detached mm but is still in the > memcg that is currently oom. This will allow the oom killer to > appropriately defer rather than kill unnecessarily or, in the worst case, > panic the machine if nothing else is available to kill. > > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> > --- > mm/memcontrol.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1110,7 +1110,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) > > p = find_lock_task_mm(task); > if (!p) > - return 0; > + return mem_cgroup_from_task(task) == memcg; > curr = try_get_mem_cgroup_from_mm(p->mm); > task_unlock(p); > if (!curr) Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>