From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
vdavydov-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org,
kernel-team-b10kYP2dOMg@public.gmane.org
Subject: Re: [PATCH 1/4] memcg: fix over-high reclaim amount
Date: Tue, 1 Sep 2015 14:33:07 -0400 [thread overview]
Message-ID: <20150901183307.GC18956@htj.dyndns.org> (raw)
In-Reply-To: <20150901125149.GD8810-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
Hello,
On Tue, Sep 01, 2015 at 02:51:50PM +0200, Michal Hocko wrote:
> > Is reclaim throughput as determined by CPU cycle bandwidth a
> > meaningful metric?
>
> Well, considering it has a direct effect on the latency I would consider
> it quite meaningful.
>
> > I'm having a bit of trouble imagining that this
> > actually would matter especially given that writeback is single
> > threaded per bdi_writeback.
>
> Sure, if the LRU contains a lot of dirty pages then the writeback will be
> a bottleneck. But LRUs are quite often full of the clean pagecache pages
> which can be reclaimed quickly and efficiently.
I see. Hmmm... I can imagine the scheduling latencies from
synchronization being a factor. Alright, if we decide to do this
return-path reclaiming, I'll update the patch to accumulate nr_pages.
Thanks.
--
tejun
next prev parent reply other threads:[~2015-09-01 18:33 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-28 15:25 [PATCHSET] memcg: improve high limit behavior and always enable kmemcg on dfl hier Tejun Heo
[not found] ` <1440775530-18630-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-08-28 15:25 ` [PATCH 1/4] memcg: fix over-high reclaim amount Tejun Heo
2015-08-28 17:06 ` Michal Hocko
[not found] ` <20150828170612.GA21463-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-08-28 18:32 ` Tejun Heo
[not found] ` <20150828183209.GA9423-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-08-31 7:51 ` Michal Hocko
[not found] ` <20150831075133.GA29723-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-08-31 13:38 ` Tejun Heo
2015-09-01 12:51 ` Michal Hocko
[not found] ` <20150901125149.GD8810-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-09-01 18:33 ` Tejun Heo [this message]
2015-08-28 15:25 ` [PATCH 2/4] memcg: flatten task_struct->memcg_oom Tejun Heo
[not found] ` <1440775530-18630-3-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-08-28 17:11 ` Michal Hocko
2015-08-28 15:25 ` [PATCH 3/4] memcg: punt high overage reclaim to return-to-userland path Tejun Heo
[not found] ` <1440775530-18630-4-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-08-28 16:36 ` Vladimir Davydov
2015-08-28 16:48 ` Tejun Heo
2015-08-28 20:32 ` Vladimir Davydov
2015-08-28 20:44 ` Tejun Heo
2015-08-28 22:06 ` Tejun Heo
[not found] ` <20150828220632.GF11089-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2015-08-29 7:59 ` Vladimir Davydov
2015-08-30 15:52 ` Vladimir Davydov
2015-08-28 17:13 ` Michal Hocko
[not found] ` <20150828171322.GC21463-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-08-28 17:56 ` Tejun Heo
2015-08-28 20:45 ` Vladimir Davydov
2015-08-28 20:53 ` Tejun Heo
[not found] ` <20150828205301.GB11089-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2015-08-28 21:07 ` Vladimir Davydov
2015-08-28 21:14 ` Tejun Heo
2015-08-28 15:25 ` [PATCH 4/4] memcg: always enable kmemcg on the default hierarchy Tejun Heo
[not found] ` <1440775530-18630-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-08-28 16:49 ` Vladimir Davydov
2015-08-28 16:56 ` Tejun Heo
2015-08-28 17:14 ` Michal Hocko
2015-08-28 17:41 ` Tejun Heo
2015-09-01 12:44 ` Michal Hocko
[not found] ` <20150901124459.GC8810-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-09-01 18:51 ` Tejun Heo
2015-09-04 13:30 ` Michal Hocko
[not found] ` <20150904133038.GC8220-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-09-04 15:38 ` Vladimir Davydov
2015-09-07 9:39 ` Michal Hocko
2015-09-07 10:01 ` Vladimir Davydov
2015-09-07 11:03 ` Michal Hocko
2015-09-04 16:18 ` Tejun Heo
[not found] ` <20150904161845.GB25329-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-09-07 10:54 ` Michal Hocko
2015-09-08 18:50 ` Tejun Heo
2015-11-05 17:30 ` Michal Hocko
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