From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@suse.de>,
Hillf Danton <hillf.zj@alibaba-inc.com>, <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 0/3 -v3] GFP_NOFAIL cleanups
Date: Tue, 20 Dec 2016 14:49:01 +0100 [thread overview]
Message-ID: <20161220134904.21023-1-mhocko@kernel.org> (raw)
Hi,
This has been posted [1] initially to later be reduced to a single patch
[2]. Johannes then suggested [3] to split up the second patch and make
the access to memory reserves by __GF_NOFAIL requests which do not
invoke the oom killer a separate change. This is patch 3 now.
Tetsuo has noticed [4] 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. We have also seen
a report where __GFP_NOFAIL|GFP_NOFS requests cause the oom killer which
is premature.
Patch 3 is an attempt to reduce chances of GFP_NOFAIL requests being
preempted by other memory consumers by giving them access to memory
reserves.
[1] http://lkml.kernel.org/r/20161123064925.9716-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/20161214150706.27412-1-mhocko@kernel.org
[3] http://lkml.kernel.org/r/20161216173151.GA23182@cmpxchg.org
[4] http://lkml.kernel.org/r/1479387004-5998-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
next reply other threads:[~2016-12-20 13:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-20 13:49 Michal Hocko [this message]
2016-12-20 13:49 ` [PATCH 1/3] mm: consolidate GFP_NOFAIL checks in the allocator slowpath Michal Hocko
2016-12-20 13:49 ` [PATCH 2/3] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically Michal Hocko
2016-12-20 15:31 ` Tetsuo Handa
2016-12-21 8:15 ` Michal Hocko
2017-01-19 18:41 ` Johannes Weiner
2017-01-20 8:33 ` Hillf Danton
2017-01-24 12:40 ` Michal Hocko
2017-01-25 7:00 ` Hillf Danton
2017-01-25 7:59 ` Michal Hocko
2017-01-25 8:41 ` Hillf Danton
2017-01-25 10:19 ` Michal Hocko
2016-12-20 13:49 ` [PATCH 3/3] mm: help __GFP_NOFAIL allocations which do not trigger OOM killer Michal Hocko
2017-01-02 15:49 ` [PATCH 0/3 -v3] GFP_NOFAIL cleanups Michal Hocko
2017-01-03 1:36 ` Tetsuo Handa
2017-01-03 8:42 ` Michal Hocko
2017-01-03 14:38 ` Tetsuo Handa
2017-01-03 16:25 ` Vlastimil Babka
2017-01-03 20:40 ` Michal Hocko
2017-01-04 14:22 ` Tetsuo Handa
2017-01-04 15:20 ` Michal Hocko
2017-01-05 10:50 ` Tetsuo Handa
2017-01-05 11:54 ` Michal Hocko
2017-01-18 18:42 ` Michal Hocko
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