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Date: Thu, 15 Dec 2016 11:28:38 +0100
From: Michal Hocko <mhocko@kernel.org>
Subject: [PATCH v2] mm: consolidate GFP_NOFAIL checks in the allocator
 slowpath
Message-ID: <20161215102838.GA8602@dhcp22.suse.cz>
References: <20161214150706.27412-1-mhocko@kernel.org>
 <04b001d256a8$7bc813d0$73583b70$@alibaba-inc.com>
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To: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: 'Andrew Morton' <akpm@linux-foundation.org>, 'Vlastimil Babka' <vbabka@suse.cz>, 'Tetsuo Handa' <penguin-kernel@I-love.SAKURA.ne.jp>, 'Johannes Weiner' <hannes@cmpxchg.org>, 'Mel Gorman' <mgorman@suse.de>, 'David Rientjes' <rientjes@google.com>, linux-mm@kvack.org, 'LKML' <linux-kernel@vger.kernel.org>

On Thu 15-12-16 15:54:37, Hillf Danton wrote:
> On Wednesday, December 14, 2016 11:07 PM Michal Hocko wrote: 
[...]
> >  	/* Avoid allocations with no watermarks from looping endlessly */
> > -	if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
> > +	if (test_thread_flag(TIF_MEMDIE))
> >  		goto nopage;
> > 
> Nit: currently we allow TIF_MEMDIE & __GFP_NOFAIL request to
> try direct reclaim. Are you intentionally reclaiming that chance?

That is definitely not a nit! Thanks for catching that. We definitely
shouldn't bypass the direct reclaim because that would mean we rely on
somebody else makes progress for us.

Updated patch below:
---