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From: Michal Hocko <mhocko@suse.cz>
To: Vinayak Menon <vinmenon@codeaurora.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	akpm@linux-foundation.org, hannes@cmpxchg.org,
	vdavydov@parallels.com, mgorman@suse.de, minchan@kernel.org
Subject: Re: [PATCH v2] mm: vmscan: fix the page state calculation in too_many_isolated
Date: Wed, 14 Jan 2015 17:50:36 +0100	[thread overview]
Message-ID: <20150114165036.GI4706@dhcp22.suse.cz> (raw)
In-Reply-To: <1421235419-30736-1-git-send-email-vinmenon@codeaurora.org>

On Wed 14-01-15 17:06:59, Vinayak Menon wrote:
[...]
> In one such instance, zone_page_state(zone, NR_ISOLATED_FILE)
> had returned 14, zone_page_state(zone, NR_INACTIVE_FILE)
> returned 92, and GFP_IOFS was set, and this resulted
> in too_many_isolated returning true. But one of the CPU's
> pageset vm_stat_diff had NR_ISOLATED_FILE as "-14". So the
> actual isolated count was zero. As there weren't any more
> updates to NR_ISOLATED_FILE and vmstat_update deffered work
> had not been scheduled yet, 7 tasks were spinning in the
> congestion wait loop for around 4 seconds, in the direct
> reclaim path.

Not syncing for such a long time doesn't sound right. I am not familiar
with the vmstat syncing but sysctl_stat_interval is HZ so it should
happen much more often that every 4 seconds.

-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2015-01-14 16:50 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-14 11:36 Vinayak Menon
2015-01-14 16:50 ` Michal Hocko [this message]
2015-01-15 17:24   ` Vinayak Menon
2015-01-16 15:49     ` Michal Hocko
2015-01-16 17:57       ` Michal Hocko
2015-01-16 19:17         ` Christoph Lameter
2015-01-17 15:18       ` Vinayak Menon
2015-01-17 19:48         ` Christoph Lameter
2015-01-19  4:27           ` Vinayak Menon
2015-01-21 14:39             ` Michal Hocko
2015-01-22 15:16               ` Vlastimil Babka
2015-01-22 16:11               ` Christoph Lameter
2015-01-26 17:46                 ` Michal Hocko
2015-01-26 18:35                   ` Christoph Lameter
2015-01-27 10:52                     ` Michal Hocko
2015-01-27 16:59                       ` Christoph Lameter
2015-01-30 15:28                         ` Michal Hocko
2015-01-26 17:28           ` Michal Hocko
2015-01-26 18:35             ` Christoph Lameter
2015-01-26 22:11             ` Andrew Morton
2015-01-27 10:41               ` Michal Hocko
2015-01-27 10:33             ` Vinayak Menon
2015-01-27 10:45               ` Michal Hocko
2015-01-29 17:32       ` Christoph Lameter
2015-01-30 15:27         ` Michal Hocko
2015-01-16  1:17 ` Andrew Morton
2015-01-16  5:10   ` Vinayak Menon
2015-01-17 16:29   ` Vinayak Menon
2015-02-11 22:14     ` Andrew Morton
2015-02-12 16:19       ` Vlastimil Babka

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