linux-kernel - [RFC 0/2] GFP

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Date:   Wed, 23 Nov 2016 07:49:23 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     <linux-mm@...ck.org>
Cc:     Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Vlastimil Babka <vbabka@...e.cz>,
        David Rientjes <rientjes@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Mel Gorman <mgorman@...e.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [RFC 0/2] GFP_NOFAIL cleanups

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