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From: Michal Hocko <mhocko@kernel.org>
To: linux-mm@kvack.org
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Vlastimil Babka <vbabka@suse.cz>,
	David Rientjes <rientjes@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Mel Gorman <mgorman@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [RFC 0/2] GFP_NOFAIL cleanups
Date: Wed, 23 Nov 2016 07:49:23 +0100	[thread overview]
Message-ID: <20161123064925.9716-1-mhocko@kernel.org> (raw)

Hi,
Tetsuo has noticed [1] that recent changes have changed GFP_NOFAIL
semantic for costly order requests. I believe that the primary reason
why this happened is that our GFP_NOFAIL checks are too scattered
and it is really easy to forget about adding one. That's why I am
proposing patch 1 which consolidates all the nofail handling at a single
place. This should help to make this code better maintainable.

Patch 2 on top is a further attempt to make GFP_NOFAIL semantic less
surprising. As things stand currently GFP_NOFAIL overrides the oom killer
prevention code which is both subtle and not really needed. The patch 2
has more details about issues this might cause.

I would consider both patches more a cleanup than anything else. Any
feedback is highly appreciated.

[1] http://lkml.kernel.org/r/1479387004-5998-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp

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             reply	other threads:[~2016-11-23  6:49 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-23  6:49 Michal Hocko [this message]
2016-11-23  6:49 ` [RFC 1/2] mm: consolidate GFP_NOFAIL checks in the allocator slowpath Michal Hocko
2016-11-23 10:43   ` Vlastimil Babka
2016-11-23  6:49 ` [RFC 2/2] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically Michal Hocko
2016-11-23 12:19   ` Vlastimil Babka
2016-11-23 12:35     ` Michal Hocko
2016-11-24  7:41       ` Vlastimil Babka
2016-11-24  7:51         ` Michal Hocko
2016-11-23 14:35   ` Tetsuo Handa
2016-11-23 15:35     ` Michal Hocko
2016-11-25 12:00       ` Tetsuo Handa
2016-11-25 13:18         ` Michal Hocko

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