Date: Tue, 8 Mar 2016 18:32:30 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>, Hugh Dickins <hughd@google.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>, Mel Gorman <mgorman@suse.de>,
        David Rientjes <rientjes@google.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Hillf Danton <hillf.zj@alibaba-inc.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>, Joonsoo Kim <js1304@gmail.com>
Subject: Re: [PATCH] mm, oom: protect !costly allocations some more
Message-ID: <20160308093230.GB3860@swordfish>
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On (03/08/16 10:24), Vlastimil Babka wrote:
[..]
> > @@ -3294,6 +3289,18 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> >  				 did_some_progress > 0, no_progress_loops))
> >  		goto retry;
> >  
> > +	/*
> > +	 * !costly allocations are really important and we have to make sure
> > +	 * the compaction wasn't deferred or didn't bail out early due to locks
> > +	 * contention before we go OOM.
> > +	 */
> > +	if (order && order <= PAGE_ALLOC_COSTLY_ORDER) {
> > +		if (compact_result <= COMPACT_CONTINUE)
> 
> Same here.
> I was going to say that this didn't have effect on Sergey's test, but
> turns out it did :)

I'm sorry, my test is not correct. I have disabled compaction last weeked on
purpose - to provoke more OOM-kills and OOM conditions for reworked printk()
patch set testing (http://marc.info/?l=linux-kernel&m=145734549308803); and I
forgot to re-enable it.

	-ss