From: Shakeel Butt <shakeelb@google.com>
To: zangchunxin@bytedance.com
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Jonathan Corbet <corbet@lwn.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
kafai@fb.com, Song Liu <songliubraving@fb.com>,
yhs@fb.com, andriin@fb.com, john.fastabend@gmail.com,
kpsingh@chromium.org, Cgroups <cgroups@vger.kernel.org>,
linux-doc@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
bpf@vger.kernel.org
Subject: Re: [PATCH] mm/memcontrol: Add the drop_cache interface for cgroup v2
Date: Mon, 21 Sep 2020 08:55:15 -0700 [thread overview]
Message-ID: <CALvZod5JpEsmNvbaCMEfRMt83GbeLJk2oM0=siCj+aXEnxYh4Q@mail.gmail.com> (raw)
In-Reply-To: <20200921080255.15505-1-zangchunxin@bytedance.com>
On Mon, Sep 21, 2020 at 1:05 AM <zangchunxin@bytedance.com> wrote:
>
> From: Chunxin Zang <zangchunxin@bytedance.com>
>
> In the cgroup v1, we have 'force_mepty' interface. This is very
> useful for userspace to actively release memory. But the cgroup
> v2 does not.
>
> This patch reuse cgroup v1's function, but have a new name for
> the interface. Because I think 'drop_cache' may be is easier to
> understand :)
>
> Signed-off-by: Chunxin Zang <zangchunxin@bytedance.com>
> ---
> Documentation/admin-guide/cgroup-v2.rst | 11 +++++++++++
> mm/memcontrol.c | 5 +++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index ce3e05e41724..fbff959c8116 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1181,6 +1181,17 @@ PAGE_SIZE multiple when read back.
> high limit is used and monitored properly, this limit's
> utility is limited to providing the final safety net.
>
> + memory.drop_cache
> + A write-only single value file which exists on non-root
> + cgroups.
> +
> + Provide a mechanism for users to actively trigger memory
> + reclaim. The cgroup will be reclaimed and as many pages
> + reclaimed as possible.
> +
> + It will broke low boundary. Because it tries to reclaim the
> + memory many times, until the memory drops to a certain level.
> +
drop_cache is not really force_empty(). What is your use-case? Maybe
you can use memory.reclaim [1] for your use-case. It is already in
Andrew's tree.
[1] https://lkml.kernel.org/r/20200909215752.1725525-1-shakeelb@google.com
prev parent reply other threads:[~2020-09-21 15:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 8:02 [PATCH] mm/memcontrol: Add the drop_cache interface for cgroup v2 zangchunxin
2020-09-21 8:12 ` Michal Hocko
2020-09-21 10:42 ` Chris Down
2020-09-21 10:55 ` Yafang Shao
2020-09-21 11:05 ` Michal Hocko
2020-09-21 11:23 ` Yafang Shao
2020-09-21 11:36 ` Michal Hocko
2020-09-22 4:20 ` Yafang Shao
2020-09-22 7:27 ` Michal Hocko
2020-09-22 8:06 ` Yafang Shao
2020-09-22 10:01 ` Michal Hocko
2020-09-22 9:43 ` [External] " Chunxin Zang
2020-09-22 9:51 ` Chris Down
2020-09-22 10:24 ` Chunxin Zang
2020-09-22 10:42 ` Chris Down
2020-09-22 12:37 ` Chunxin Zang
2020-09-22 12:43 ` Chris Down
2020-09-23 2:35 ` Chunxin Zang
2020-09-22 19:57 ` Shakeel Butt
2020-09-23 2:40 ` Chunxin Zang
2020-09-21 15:55 ` Shakeel Butt [this message]
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