On Mon 27-04-15 15:05:54, Johannes Weiner wrote: > There is not much point in rushing back to the freelists and burning > CPU cycles in direct reclaim when somebody else is in the process of > OOM killing, or right after issuing a kill ourselves, because it could > take some time for the OOM victim to release memory. > > This is a very cold error path, so there is not much hurry. Use the > OOM victim waitqueue to wait for victims to actually exit, which is a > solid signal that the memory pinned by those tasks has been released. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Looks good to me. One minor thing/suggestion below. Acked-by: Michal Hocko <mhocko@xxxxxxx> > --- > mm/oom_kill.c | 11 +++++++---- > mm/page_alloc.c | 43 ++++++++++++++++++++++++++----------------- > 2 files changed, 33 insertions(+), 21 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 5cfda39..823f87e 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -711,12 +711,15 @@ bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, > killed = 1; > } > out: > + if (test_thread_flag(TIF_MEMDIE)) > + return true; > /* > - * Give the killed threads a good chance of exiting before trying to > - * allocate memory again. > + * Wait for any outstanding OOM victims to die. In rare cases > + * victims can get stuck behind the allocating tasks, so the > + * wait needs to be bounded. It's crude alright, but cheaper > + * than keeping a global dependency tree between all tasks. > */ > - if (killed) > - schedule_timeout_killable(1); > + wait_event_timeout(oom_victims_wait, !atomic_read(&oom_victims), 5*HZ); WARN(!wait_event_timeout(...), "OOM victim has hard time to finish. OOM deadlock?") or something along those lines? It would tell the admin that something fishy is going here. > > return true; > } [...] -- Michal Hocko SUSE Labs -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>