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From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>, Tejun Heo <tj@kernel.org>,
	Roman Gushchin <guro@fb.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry().
Date: Wed, 5 Sep 2018 16:04:51 +0200	[thread overview]
Message-ID: <20180905140451.GG14951@dhcp22.suse.cz> (raw)
In-Reply-To: <81cc1f29-e42e-7813-dc70-5d6d9e999dd1@i-love.sakura.ne.jp>

On Wed 05-09-18 22:53:33, Tetsuo Handa wrote:
> On 2018/09/05 22:40, Michal Hocko wrote:
> > Changelog said 
> > 
> > "Although this is possible in principle let's wait for it to actually
> > happen in real life before we make the locking more complex again."
> > 
> > So what is the real life workload that hits it? The log you have pasted
> > below doesn't tell much.
> 
> Nothing special. I just ran a multi-threaded memory eater on a CONFIG_PREEMPT=y kernel.

I strongly suspec that your test doesn't really represent or simulate
any real and useful workload. Sure it triggers a rare race and we kill
another oom victim. Does this warrant to make the code more complex?
Well, I am not convinced, as I've said countless times.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-09-05 14:04 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-26 11:06 Tetsuo Handa
2018-07-26 11:39 ` Michal Hocko
2018-07-27 15:47   ` Tetsuo Handa
2018-07-30  9:32     ` Michal Hocko
2018-07-30 14:34       ` Tetsuo Handa
2018-07-30 14:46         ` Michal Hocko
2018-07-30 14:54           ` Tejun Heo
2018-07-30 15:25             ` Tetsuo Handa
2018-07-30 15:44               ` Tejun Heo
2018-07-30 18:51                 ` Michal Hocko
2018-07-30 19:10                   ` Michal Hocko
2018-07-30 21:01                     ` Tetsuo Handa
2018-07-31  5:09                       ` Michal Hocko
2018-07-31 10:47                         ` Tetsuo Handa
2018-07-31 11:15                           ` Michal Hocko
2018-07-31 11:30                             ` Tetsuo Handa
2018-07-31 11:55                               ` Michal Hocko
2018-08-02 22:05                         ` Tetsuo Handa
2018-08-03  6:16                           ` Michal Hocko
2018-08-21 21:07                             ` Tetsuo Handa
2018-08-22  7:32                               ` Michal Hocko
2018-08-23 20:06                               ` David Rientjes
2018-08-23 21:00                                 ` Tetsuo Handa
2018-08-23 22:45                                   ` David Rientjes
2018-08-24  0:31                                     ` Tetsuo Handa
2018-09-05 13:20                                       ` Tetsuo Handa
2018-09-05 13:40                                         ` Michal Hocko
2018-09-05 13:53                                           ` Tetsuo Handa
2018-09-05 14:04                                             ` Michal Hocko [this message]
2018-09-06  1:00                                               ` Tetsuo Handa
2018-09-06  5:57                                                 ` Michal Hocko
2018-09-06  6:22                                                   ` Tetsuo Handa
2018-09-06  7:03                                                   ` Tetsuo Handa
2018-07-30 19:14                   ` Tejun Heo
2018-08-27 13:51 Michal Hocko

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