From: Michal Hocko <mhocko@kernel.org>
To: Fam Zheng <zhengfeiran@bytedance.com>
Cc: "Yang Shi" <shy828301@gmail.com>,
cgroups@vger.kernel.org, "Linux MM" <linux-mm@kvack.org>,
tj@kernel.org, "Johannes Weiner" <hannes@cmpxchg.org>,
lizefan@huawei.com, "Vladimir Davydov" <vdavydov.dev@gmail.com>,
duanxiongchun@bytedance.com, 张永肃 <zhangyongsu@bytedance.com>,
liuxiaozhou@bytedance.com
Subject: Re: memory cgroup pagecache and inode problem
Date: Mon, 7 Jan 2019 09:53:16 +0100 [thread overview]
Message-ID: <20190107085316.GY31793@dhcp22.suse.cz> (raw)
In-Reply-To: <E2306860-760C-4EB2-92E3-057694971D69@bytedance.com>
On Mon 07-01-19 13:10:17, Fam Zheng wrote:
>
>
> > On Jan 5, 2019, at 03:36, Yang Shi <shy828301@gmail.com> wrote:
> >
> >
> > drop_caches would drop all page caches globally. You may not want to
> > drop the page caches used by other memcgs.
>
> We’ve tried your async force_empty patch (with a modification to default it to true to make it transparently enabled for the sake of testing), and for the past few days the stale mem cgroups still accumulate, up to 40k.
>
> We’ve double checked that the force_empty routines are invoked when a mem cgroup is offlined. But this doesn’t look very effective so far. Because, once we do `echo 1 > /proc/sys/vm/drop_caches`, all the groups immediately go away.
>
> This is a bit unexpected.
>
> Yang, could you hint what are missing in the force_empty operation, compared to a blanket drop cache?
I would suspect that not all slab pages holding dentries and inodes got
reclaimed during the slab shrinking inoked by the direct reclaimed
triggered by force emptying.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-01-07 8:53 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <15614FDC-198E-449B-BFAF-B00D6EF61155@bytedance.com>
2019-01-04 4:44 ` memory cgroup pagecache and inode problem Fam Zheng
2019-01-04 5:00 ` Yang Shi
2019-01-04 5:12 ` Fam Zheng
2019-01-04 19:36 ` Yang Shi
2019-01-07 5:10 ` Fam Zheng
2019-01-07 8:53 ` Michal Hocko [this message]
2019-01-07 9:01 ` Fam Zheng
2019-01-07 9:13 ` Michal Hocko
2019-01-09 4:33 ` Fam Zheng
2019-01-10 5:36 ` Yang Shi
2019-01-10 8:30 ` Fam Zheng
2019-01-10 8:41 ` Michal Hocko
2019-01-16 0:50 ` Yang Shi
2019-01-16 3:52 ` Fam Zheng
2019-01-16 7:06 ` Michal Hocko
2019-01-16 21:08 ` Yang Shi
2019-01-16 21:06 ` Yang Shi
2019-01-17 2:41 ` Fam Zheng
2019-01-17 5:06 ` Yang Shi
2019-01-19 3:17 ` 段熊春
2019-01-20 23:15 ` Shakeel Butt
2019-01-20 23:15 ` Shakeel Butt
2019-01-20 23:20 ` Shakeel Butt
2019-01-21 10:27 ` Michal Hocko
2019-01-04 9:04 ` Michal Hocko
2019-01-04 10:02 ` Fam Zheng
2019-01-04 10:12 ` Michal Hocko
2019-01-04 10:35 ` Fam Zheng
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