From: David Rientjes <rientjes@google.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: mhocko@suse.com, linux-mm@kvack.org
Subject: Re: [PATCH 1/2] mm,oom_reaper: Show trace of unable to reap victim thread.
Date: Tue, 20 Mar 2018 13:46:51 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1803201341210.167205@chino.kir.corp.google.com> (raw)
In-Reply-To: <201803202320.IDG60953.QOFOFVFSLOHtMJ@I-love.SAKURA.ne.jp>
On Tue, 20 Mar 2018, Tetsuo Handa wrote:
> > I am no questioning that. I am questioning the additional information
> > because we won't be able to do anything about mmap_sem holder most of
> > the time. Because they tend block on allocations...
>
> serial-20180320.txt.xz is saying that they tend to block on i_mmap_lock_write() rather
> than memory allocations. Making memory allocations killable will need a lot of work.
> But I think that making frequently hitting down_write() killable won't need so much work.
>
I have available to me more than 28,222,058 occurrences of successful oom
reaping and 13,018 occurrences of failing to grab mm->mmap_sem.
The number of failures is low on production workloads, so I don't see an
issue with emitting a stack trace in these instances if it can help
improve things. But for my 0.04% failure rate, I can't say that I would
look into them much unless it results in the system livelocking. Unless
there's a compelling reason why this is shouldn't be done (too much email
sent to linux-mm as a result? :), I say just go ahead and add the darn
stack trace.
prev parent reply other threads:[~2018-03-20 20:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 11:57 [PATCH 1/2] mm,oom_reaper: Show trace of unable to reap victim thread Tetsuo Handa
2018-03-20 11:57 ` [PATCH 2/2] mm,oom_reaper: Correct MAX_OOM_REAP_RETRIES'th attempt Tetsuo Handa
2018-03-20 12:12 ` Michal Hocko
2018-03-20 12:37 ` Tetsuo Handa
2018-03-20 12:47 ` [PATCH 2/2] mm,oom_reaper: Check for MMF_OOM_SKIP before complain Tetsuo Handa
2018-03-20 20:49 ` David Rientjes
2018-03-22 10:46 ` [PATCH] " Tetsuo Handa
2018-03-22 11:59 ` Michal Hocko
2018-03-20 13:24 ` [PATCH 2/2] mm,oom_reaper: Correct MAX_OOM_REAP_RETRIES'th attempt Michal Hocko
2018-03-20 13:37 ` Tetsuo Handa
2018-03-20 13:44 ` Michal Hocko
2018-03-20 12:28 ` [PATCH 1/2] mm,oom_reaper: Show trace of unable to reap victim thread Michal Hocko
2018-03-20 12:52 ` Tetsuo Handa
2018-03-20 13:19 ` Michal Hocko
2018-03-20 13:30 ` Tetsuo Handa
2018-03-20 13:34 ` Michal Hocko
2018-03-20 13:50 ` Tetsuo Handa
2018-03-20 14:10 ` Michal Hocko
2018-03-20 14:20 ` Tetsuo Handa
2018-03-20 20:46 ` David Rientjes [this message]
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