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From: Michal Hocko <mhocko@kernel.org>
To: Bruce Merry <bmerry@ska.ac.za>
Cc: Shakeel Butt <shakeelb@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux MM <linux-mm@kvack.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: Showing /sys/fs/cgroup/memory/memory.stat very slow on some machines
Date: Wed, 25 Jul 2018 14:32:37 +0200	[thread overview]
Message-ID: <20180725123237.GI28386@dhcp22.suse.cz> (raw)
In-Reply-To: <CAOm-9aqYLExQZUvfk9ucCoSPoaA67D6ncEDR2+UZBMLhv4-r_A@mail.gmail.com>

On Tue 24-07-18 12:05:35, Bruce Merry wrote:
[...]
> I've also added some code to memcg_stat_show to report the number of
> cgroups in the hierarchy (iterations in for_each_mem_cgroup_tree).
> Running the script increases it from ~700 to ~41000. The script
> iterates 250,000 times, so only some fraction of the cgroups become
> zombies.

So this is definitely "too many zombies" to delay the collecting of
cumulative stats. Maybe we need to limit the number of zombies and
reclaim them more actively. I have seen Shakeel has posted something but
it looked more on the accounting side from a quick glance.

I can see you are using cgroup v1 so your workaround would be to
memory.force_empty before you remove the group.

-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2018-07-25 12:32 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAOm-9arwY3VLUx5189JAR9J7B=Miad9nQjjet_VNdT3i+J+5FA@mail.gmail.com>
2018-07-18  4:23 ` Andrew Morton
2018-07-18 10:42   ` Michal Hocko
2018-07-18 14:29     ` Bruce Merry
2018-07-18 14:47       ` Michal Hocko
2018-07-18 15:27         ` Bruce Merry
2018-07-18 15:33           ` Shakeel Butt
2018-07-18 15:26       ` Shakeel Butt
2018-07-18 15:37         ` Bruce Merry
2018-07-18 15:49           ` Shakeel Butt
2018-07-18 17:40             ` Bruce Merry
2018-07-18 17:48               ` Shakeel Butt
2018-07-18 17:58                 ` Bruce Merry
2018-07-18 18:13                   ` Shakeel Butt
2018-07-18 18:43                     ` Bruce Merry
2018-07-24 10:05               ` Bruce Merry
2018-07-24 10:50                 ` Marinko Catovic
2018-07-25 12:29                   ` Michal Hocko
2018-07-25 12:32                 ` Michal Hocko [this message]
2018-07-26 12:35                 ` Bruce Merry
2018-07-26 12:48                   ` Michal Hocko
2018-07-26  0:55               ` Singh, Balbir
2018-07-26  6:41                 ` Bruce Merry
2018-07-26  8:19                   ` Michal Hocko

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