Andrew, could you queue this one as well, please? This is more a band aid than a real solution which I will be working on as soon as I am able to reproduce the issue but the patch should help to some degree at least. On Thu 25-02-16 10:23:15, Michal Hocko wrote: > From d09de26cee148b4d8c486943b4e8f3bd7ad6f4be Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxxx> > Date: Thu, 4 Feb 2016 14:56:59 +0100 > Subject: [PATCH] mm, oom: protect !costly allocations some more > > should_reclaim_retry will give up retries for higher order allocations > if none of the eligible zones has any requested or higher order pages > available even if we pass the watermak check for order-0. This is done > because there is no guarantee that the reclaimable and currently free > pages will form the required order. > > This can, however, lead to situations were the high-order request (e.g. > order-2 required for the stack allocation during fork) will trigger > OOM too early - e.g. after the first reclaim/compaction round. Such a > system would have to be highly fragmented and the OOM killer is just a > matter of time but let's stick to our MAX_RECLAIM_RETRIES for the high > order and not costly requests to make sure we do not fail prematurely. > > This also means that we do not reset no_progress_loops at the > __alloc_pages_slowpath for high order allocations to guarantee a bounded > number of retries. > > Longterm it would be much better to communicate with the compaction > and retry only if the compaction considers it meaningfull. > > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/page_alloc.c | 20 ++++++++++++++++---- > 1 file changed, 16 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 269a04f20927..f05aca36469b 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3106,6 +3106,18 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order, > } > } > > + /* > + * OK, so the watermak check has failed. Make sure we do all the > + * retries for !costly high order requests and hope that multiple > + * runs of compaction will generate some high order ones for us. > + * > + * XXX: ideally we should teach the compaction to try _really_ hard > + * if we are in the retry path - something like priority 0 for the > + * reclaim > + */ > + if (order && order <= PAGE_ALLOC_COSTLY_ORDER) > + return true; > + > return false; > } > > @@ -3281,11 +3293,11 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > goto noretry; > > /* > - * Costly allocations might have made a progress but this doesn't mean > - * their order will become available due to high fragmentation so do > - * not reset the no progress counter for them > + * High order allocations might have made a progress but this doesn't > + * mean their order will become available due to high fragmentation so > + * do not reset the no progress counter for them > */ > - if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) > + if (did_some_progress && !order) > no_progress_loops = 0; > else > no_progress_loops++; > -- > 2.7.0 > > -- > Michal Hocko > SUSE Labs -- 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>