From: Yafang Shao <laoar.shao@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>, Linux MM <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/4] memcg, inode: protect page cache from freeing inode
Date: Tue, 17 Dec 2019 20:19:08 +0800 [thread overview]
Message-ID: <CALOAHbBQ+XkQk6HN53O4e1=qfFiow2kvQO3ajDj=fwQEhcZ3uw@mail.gmail.com> (raw)
In-Reply-To: <20191217115603.GA10016@dhcp22.suse.cz>
On Tue, Dec 17, 2019 at 7:56 PM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Tue 17-12-19 06:29:15, Yafang Shao wrote:
> > On my server there're some running MEMCGs protected by memory.{min, low},
> > but I found the usage of these MEMCGs abruptly became very small, which
> > were far less than the protect limit. It confused me and finally I
> > found that was because of inode stealing.
>
> What do you mean by this exactly. Are those inodes reclaimed by the
> regular memory reclaim or by other means? Because shrink_node does
> exclude shrinking slab for protected memcgs.
By the regular memory reclaim, kswapd, direct reclaimer or memcg reclaimer.
IOW, the current->reclaim_state it set.
Take an example for you.
kswapd
balance_pgdat
shrink_node_memcgs
switch (mem_cgroup_protected) <<<< memory.current= 1024M
memory.min = 512M a file has 800M page caches
case MEMCG_PROT_NONE: <<<< hard limit is not reached.
beak;
shrink_lruvec
shrink_slab <<< it may free the inode and the free all its
page caches (800M)
Hope it could clarify.
Thanks
Yafang
next prev parent reply other threads:[~2019-12-17 12:19 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 11:29 [PATCH 0/4] memcg, inode: protect page cache from freeing inode Yafang Shao
2019-12-17 11:29 ` [PATCH 1/4] mm, memcg: reduce size of struct mem_cgroup by using bit field Yafang Shao
2019-12-17 11:29 ` [PATCH 2/4] mm, memcg: introduce MEMCG_PROT_SKIP for memcg zero usage case Yafang Shao
2019-12-17 11:29 ` [PATCH 3/4] mm, memcg: reset memcg's memory.{min, low} for reclaiming itself Yafang Shao
2019-12-17 14:20 ` Chris Down
2019-12-18 1:13 ` Yafang Shao
2019-12-17 11:29 ` [PATCH 4/4] memcg, inode: protect page cache from freeing inode Yafang Shao
2019-12-18 2:21 ` Dave Chinner
2019-12-18 2:33 ` Yafang Shao
2019-12-18 17:53 ` Roman Gushchin
2019-12-19 1:45 ` Yafang Shao
2019-12-17 11:56 ` [PATCH 0/4] " Michal Hocko
2019-12-17 12:19 ` Yafang Shao [this message]
2019-12-17 16:54 ` Johannes Weiner
2019-12-18 1:17 ` Yafang Shao
2019-12-18 1:37 ` Andrew Morton
2019-12-18 1:51 ` Dave Chinner
2019-12-18 4:37 ` Johannes Weiner
2019-12-18 10:16 ` Dave Chinner
2019-12-18 21:38 ` Johannes Weiner
2019-12-19 2:04 ` Yafang Shao
2020-01-10 2:08 ` Dave Chinner
2019-12-18 17:27 ` Roman Gushchin
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