From: Tejun Heo <tj@kernel.org>
To: gregkh@linuxfoundation.org, lizefan@huawei.com, hannes@cmpxchg.org
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCHSET] kernfs, cgroup: reimplement "cgroup.procs" reading for v2
Date: Tue, 27 Dec 2016 14:53:54 -0500 [thread overview]
Message-ID: <20161227195354.GC31771@htj.duckdns.org> (raw)
In-Reply-To: <20161220161222.15234-1-tj@kernel.org>
On Tue, Dec 20, 2016 at 11:12:17AM -0500, Tejun Heo wrote:
> On cgroup v1, the pid listings in "cgroup.procs" and "tasks" are
> sorted which adds a lot of complications and overhead. v2 doesn't
> have such requirement and has been intentionally using a modified
> sorting order so that the output doesn't look sorted to users.
>
> This patchset re-implements "cgroup.procs" reading for v2 which simply
> keeps a css_task_iter open while the file is being read. Keeping the
> iterator open makes it unnecessary to skip to the right position on
> each read segment and associated errors - e.g. incorrectly skipping
> over pids because earlier pids disappeared between the reads.
>
> Using persistent iterator across multiple read calls requires
> ->release() callback to clean it up. kernfs operations
> ->open/release() are added and piped through cftype.
Applied to cgroup/for-4.11.
--
tejun
next prev parent reply other threads:[~2016-12-27 20:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-20 16:12 [PATCHSET] kernfs, cgroup: reimplement "cgroup.procs" reading for v2 Tejun Heo
2016-12-20 16:12 ` [PATCH 1/5] kernfs: make kernfs_open_file->mmapped a bitfield Tejun Heo
2016-12-20 16:12 ` [PATCH 2/5] kernfs: add kernfs_ops->open/release() callbacks Tejun Heo
2016-12-20 16:12 ` [PATCH 3/5] cgroup add cftype->open/release() callbacks Tejun Heo
2016-12-20 16:12 ` [PATCH 4/5] cgroup: reimplement reading "cgroup.procs" on cgroup v2 Tejun Heo
2016-12-20 16:12 ` [PATCH 5/5] cgroup: remove cgroup_pid_fry() and friends Tejun Heo
2016-12-21 9:59 ` [PATCHSET] kernfs, cgroup: reimplement "cgroup.procs" reading for v2 Greg KH
2016-12-26 6:22 ` Zefan Li
2016-12-27 19:53 ` Tejun Heo [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-12-20 16:10 Tejun Heo
2016-12-20 16:17 ` Tejun Heo
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