From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [PATCHSET cgroup/for-3.12] cgroup: decouple cgroup_subsys_state lifetime from that of cgroup Date: Tue, 13 Aug 2013 09:19:06 +0800 Message-ID: <5209898A.6040304@huawei.com> References: <1375992831-4650-1-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1375992831-4650-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Tejun Heo Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 2013/8/9 4:13, Tejun Heo wrote: > Hello, > > Currently a css's (cgroup_subsys_state) lifetime is tied to that of > the cgroup it's attached to. css's are created when the cgroup is > created and destroyed together. The access rules depend on it too - > e.g. css's can be dereferenced while holding RCU read lock because > cgroup is protected with RCU. > > With the planned unified hierarchy, we'll be dynamically creating and > destroying css's through the lifetime of a cgroup, so we can no longer > hitch css lifetime management onto cgroup's. This patchset separates > out css lifetime management from that of cgroup. After the patchset, > each css is individually RCU protected. > > This patchset contains the following 14 patches. > > 0001-cgroup-always-use-cgroup_css.patch > 0002-cgroup-rename-cgroup_subsys_state-dput_work-and-its-.patch > 0003-cgroup-add-cgroup_subsys_state-parent.patch > 0004-cgroup-cgroup_css_from_dir-now-should-be-called-with.patch > 0005-cgroup-make-cgroup_file_open-rcu_read_lock-around-cg.patch > 0006-cgroup-add-__rcu-modifier-to-cgroup-subsys.patch > 0007-cgroup-reorganize-css-init-exit-paths.patch > 0008-cgroup-move-cgroup-subsys-assignment-to-online_css.patch > 0009-cgroup-bounce-cgroup_subsys_state-ref-kill-confirmat.patch > 0010-cgroup-replace-cgroup-css_kill_cnt-with-nr_css.patch > 0011-cgroup-decouple-cgroup_subsys_state-destruction-from.patch > 0012-cgroup-factor-out-kill_css.patch > 0013-cgroup-move-subsys-file-removal-to-kill_css.patch > 0014-cgroup-RCU-protect-each-cgroup_subsys_state-release.patch > Acked-by: Li Zefan