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From: Christoph Lameter <cl@linux.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, mhocko@kernel.org,
	rientjes@google.com, oleg@redhat.com, kwalker@redhat.com,
	akpm@linux-foundation.org, hannes@cmpxchg.org,
	vdavydov@parallels.com, skozina@redhat.com, mgorman@suse.de,
	riel@redhat.com
Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks
Date: Wed, 21 Oct 2015 09:22:40 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.20.1510210920200.5611@east.gentwo.org> (raw)
In-Reply-To: <201510212126.JIF90648.HOOFJVFQLMStOF@I-love.SAKURA.ne.jp>

On Wed, 21 Oct 2015, Tetsuo Handa wrote:

> However, if a workqueue which is processed before vmstat_update
> workqueue is processed got stuck inside memory allocation request,
> values in vm_stat_diff[] cannot be merged into vm_stat[]. As a result,
> zone_reclaimable() continues using outdated vm_stat[] values and the
> task which is doing direct reclaim path thinks that there are reclaimable
> pages and therefore continues looping. The consequence is a silent
> livelock (hang up without any kernel messages) because the OOM killer
> will not be invoked.

The diffs will be merged if they reach a certain threshold regardless. You
can decrease that threshhold. See calculate_pressure_threshhold().

Why is the merging not occurring if a process gets stuck? Workrequests are
not blocked by a process being stuck doing memory allocation or reclaim.

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  parent reply	other threads:[~2015-10-21 14:22 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-21 12:26 Tetsuo Handa
2015-10-21 13:03 ` Michal Hocko
2015-10-21 14:22 ` Christoph Lameter [this message]
2015-10-21 14:33   ` Michal Hocko
2015-10-21 14:49     ` Christoph Lameter
2015-10-21 14:55       ` Michal Hocko
2015-10-21 15:39         ` Tetsuo Handa
2015-10-21 17:16         ` Christoph Lameter
2015-10-22 11:37           ` Tetsuo Handa
2015-10-22 13:39             ` Christoph Lameter
2015-10-22 14:09               ` Tejun Heo
2015-10-22 14:21                 ` Tejun Heo
2015-10-22 14:23                   ` Christoph Lameter
2015-10-22 14:24                     ` Tejun Heo
2015-10-22 14:25                       ` Christoph Lameter
2015-10-22 14:33                         ` Tejun Heo
2015-10-22 14:41                           ` Christoph Lameter
2015-10-22 15:14                             ` Tejun Heo
2015-10-23  4:26                               ` Tejun Heo
2015-11-02 15:01                                 ` Michal Hocko
2015-11-02 19:20                                   ` Tejun Heo
2015-11-03  2:32                                     ` Tetsuo Handa
2015-11-03 19:43                                       ` Tejun Heo
2015-11-05 14:59                                   ` Tetsuo Handa
2015-11-05 17:45                                     ` Christoph Lameter
2015-11-06  0:16                                       ` Tejun Heo
2015-11-11 15:44                                         ` Michal Hocko
2015-11-11 16:03                                           ` Michal Hocko
2015-10-22 14:22                 ` Christoph Lameter
2015-10-22 15:06                 ` Michal Hocko
2015-10-22 15:15                   ` Tejun Heo
2015-10-22 15:33                     ` Christoph Lameter
2015-10-23  8:37                       ` Michal Hocko
2015-10-23 11:43                         ` Make vmstat deferrable again (was Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks) Christoph Lameter
2015-10-23 12:07                           ` Sergey Senozhatsky
2015-10-23 14:12                             ` Christoph Lameter
2015-10-23 14:49                               ` Sergey Senozhatsky
2015-10-23 16:10                                 ` Christoph Lameter
2015-10-22 15:35                     ` [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks Michal Hocko
2015-10-22 15:37                       ` Tejun Heo
2015-10-22 15:49                         ` Michal Hocko
2015-10-22 18:42                           ` Tejun Heo
2015-10-22 21:42                             ` [PATCH] mm,vmscan: Use accurate values for zone_reclaimable()checks Tetsuo Handa
2015-10-22 22:47                               ` Tejun Heo
2015-10-23  8:36                               ` Michal Hocko
2015-10-23 10:37                                 ` Tejun Heo
2015-10-23  8:33                             ` [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks Michal Hocko
2015-10-23 10:36                               ` Tejun Heo
2015-10-23 11:11                                 ` Michal Hocko
2015-10-23 12:25                                   ` Tetsuo Handa
2015-10-23 18:23                                     ` Tejun Heo
2015-10-25 10:52                                       ` Tetsuo Handa
2015-10-25 22:47                                         ` Tejun Heo
2015-10-27  9:22                                         ` Michal Hocko
2015-10-27 10:55                                           ` Tejun Heo
2015-10-27 12:07                                             ` Michal Hocko
2015-10-23 18:21                                   ` Tejun Heo
2015-10-27  9:16                                     ` Michal Hocko
2015-10-27 10:52                                       ` Tejun Heo
2015-10-27 11:07                                       ` [PATCH] mm,vmscan: Use accurate values for zone_reclaimable()checks Tetsuo Handa
2015-10-27 11:30                                         ` Tejun Heo

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