From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: mhocko@suse.com
Cc: linux-mm@kvack.org, rientjes@google.com
Subject: Re: [PATCH 1/2] mm,oom_reaper: Show trace of unable to reap victim thread.
Date: Tue, 20 Mar 2018 22:30:16 +0900 [thread overview]
Message-ID: <201803202230.HDH17140.OFtMQJVLOOFHSF@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20180320131953.GM23100@dhcp22.suse.cz>
Michal Hocko wrote:
> On Tue 20-03-18 21:52:33, Tetsuo Handa wrote:
> > Michal Hocko wrote:
> > > A single stack trace in the changelog would be sufficient IMHO.
> > > Appart from that. What do you expect users will do about this trace?
> > > Sure they will see a path which holds mmap_sem, we will see a bug report
> > > but we can hardly do anything about that. We simply cannot drop the lock
> > > from that path in 99% of situations. So _why_ do we want to add more
> > > information to the log?
> >
> > This case is blocked at i_mmap_lock_write().
>
> But why does i_mmap_lock_write matter for oom_reaping. We are not
> touching hugetlb mappings. dup_mmap holds mmap_sem for write which is
> the most probable source of the backoff.
If i_mmap_lock_write can bail out upon SIGKILL, the OOM victim will be able to
release mmap_sem held for write, which helps the OOM reaper not to back off.
next prev parent reply other threads:[~2018-03-20 13:30 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 [this message]
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
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