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authorMichal Hocko <mhocko@suse.com>2016-03-26 00:20:33 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-26 02:37:42 +0300
commit03049269de433cb5fe2859be9ae4469ceb1163ed (patch)
tree29b36a160a7c4686b1e03cbc6c80908e0fbf08ed /include
parentbc448e897b6d24aae32701763b8a1fe15d29fa26 (diff)
downloadlinux-03049269de433cb5fe2859be9ae4469ceb1163ed.tar.xz
mm, oom_reaper: implement OOM victims queuing
wake_oom_reaper has allowed only 1 oom victim to be queued. The main reason for that was the simplicity as other solutions would require some way of queuing. The current approach is racy and that was deemed sufficient as the oom_reaper is considered a best effort approach to help with oom handling when the OOM victim cannot terminate in a reasonable time. The race could lead to missing an oom victim which can get stuck out_of_memory wake_oom_reaper cmpxchg // OK oom_reaper oom_reap_task __oom_reap_task oom_victim terminates atomic_inc_not_zero // fail out_of_memory wake_oom_reaper cmpxchg // fails task_to_reap = NULL This race requires 2 OOM invocations in a short time period which is not very likely but certainly not impossible. E.g. the original victim might have not released a lot of memory for some reason. The situation would improve considerably if wake_oom_reaper used a more robust queuing. This is what this patch implements. This means adding oom_reaper_list list_head into task_struct (eat a hole before embeded thread_struct for that purpose) and a oom_reaper_lock spinlock for queuing synchronization. wake_oom_reaper will then add the task on the queue and oom_reaper will dequeue it. Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/sched.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 478b41de7f7d..788f223f8f8f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1849,6 +1849,9 @@ struct task_struct {
unsigned long task_state_change;
#endif
int pagefault_disabled;
+#ifdef CONFIG_MMU
+ struct list_head oom_reaper_list;
+#endif
/* CPU-specific state of this task */
struct thread_struct thread;
/*