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
WARNING: multiple messages have this Message-ID (diff)
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
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next prev parent reply other threads:[~2015-01-14 16:50 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-14 11:36 [PATCH v2] mm: vmscan: fix the page state calculation in too_many_isolated Vinayak Menon
2015-01-14 11:36 ` Vinayak Menon
2015-01-14 16:50 ` Michal Hocko [this message]
2015-01-14 16:50 ` Michal Hocko
2015-01-15 17:24 ` Vinayak Menon
2015-01-15 17:24 ` Vinayak Menon
2015-01-16 15:49 ` Michal Hocko
2015-01-16 15:49 ` Michal Hocko
2015-01-16 17:57 ` Michal Hocko
2015-01-16 17:57 ` Michal Hocko
2015-01-16 19:17 ` Christoph Lameter
2015-01-16 19:17 ` Christoph Lameter
2015-01-17 15:18 ` Vinayak Menon
2015-01-17 15:18 ` Vinayak Menon
2015-01-17 19:48 ` Christoph Lameter
2015-01-17 19:48 ` Christoph Lameter
2015-01-19 4:27 ` Vinayak Menon
2015-01-19 4:27 ` Vinayak Menon
2015-01-21 14:39 ` Michal Hocko
2015-01-21 14:39 ` Michal Hocko
2015-01-22 15:16 ` Vlastimil Babka
2015-01-22 15:16 ` Vlastimil Babka
2015-01-22 16:11 ` Christoph Lameter
2015-01-22 16:11 ` Christoph Lameter
2015-01-26 17:46 ` Michal Hocko
2015-01-26 17:46 ` Michal Hocko
2015-01-26 18:35 ` Christoph Lameter
2015-01-26 18:35 ` Christoph Lameter
2015-01-27 10:52 ` Michal Hocko
2015-01-27 10:52 ` Michal Hocko
2015-01-27 16:59 ` Christoph Lameter
2015-01-27 16:59 ` Christoph Lameter
2015-01-30 15:28 ` Michal Hocko
2015-01-30 15:28 ` Michal Hocko
2015-01-26 17:28 ` Michal Hocko
2015-01-26 17:28 ` Michal Hocko
2015-01-26 18:35 ` Christoph Lameter
2015-01-26 18:35 ` Christoph Lameter
2015-01-26 22:11 ` Andrew Morton
2015-01-26 22:11 ` Andrew Morton
2015-01-27 10:41 ` Michal Hocko
2015-01-27 10:41 ` Michal Hocko
2015-01-27 10:33 ` Vinayak Menon
2015-01-27 10:33 ` Vinayak Menon
2015-01-27 10:45 ` Michal Hocko
2015-01-27 10:45 ` Michal Hocko
2015-01-29 17:32 ` Christoph Lameter
2015-01-29 17:32 ` Christoph Lameter
2015-01-30 15:27 ` Michal Hocko
2015-01-30 15:27 ` Michal Hocko
2015-01-16 1:17 ` Andrew Morton
2015-01-16 1:17 ` Andrew Morton
2015-01-16 5:10 ` Vinayak Menon
2015-01-16 5:10 ` Vinayak Menon
2015-01-17 16:29 ` Vinayak Menon
2015-01-17 16:29 ` Vinayak Menon
2015-02-11 22:14 ` Andrew Morton
2015-02-11 22:14 ` Andrew Morton
2015-02-12 16:19 ` Vlastimil Babka
2015-02-12 16:19 ` Vlastimil Babka
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