From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH 15/23] cgroup: make hierarchy iterators deal with cgroup_subsys_state instead of cgroup Date: Mon, 5 Aug 2013 10:25:57 -0400 Message-ID: <20130805142557.GA6440@redhat.com> References: <1375393801-4817-1-git-send-email-tj@kernel.org> <1375393801-4817-16-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1375393801-4817-16-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: Jens Axboe , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko , Johannes Weiner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Thu, Aug 01, 2013 at 05:49:53PM -0400, Tejun Heo wrote: > cgroup is currently in the process of transitioning to using css > (cgroup_subsys_state) as the primary handle instead of cgroup in > subsystem API. For hierarchy iterators, this is beneficial because > > * In most cases, css is the only thing subsystems care about anyway. > > * On the planned unified hierarchy, iterations for different > subsystems will need to skip over different subtrees of the > hierarchy depending on which subsystems are enabled on each cgroup. > Passing around css makes it unnecessary to explicitly specify the > subsystem in question as css is intersection between cgroup and > subsystem > > * For the planned unified hierarchy, css's would need to be created > and destroyed dynamically independent from cgroup hierarchy. Having > cgroup core manage css iteration makes enforcing deref rules a lot > easier. > > Most subsystem conversions are straight-forward. Noteworthy changes > are > > * blkio: cgroup_to_blkcg() is no longer used. Removed. > > * freezer: cgroup_freezer() is no longer used. Removed. > > * devices: cgroup_to_devcgroup() is no longer used. Removed. > > Signed-off-by: Tejun Heo > Cc: Li Zefan > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Balbir Singh > Cc: Aristeu Rozanski > Cc: Matt Helsley > Cc: Vivek Goyal > Cc: Jens Axboe > --- > block/blk-cgroup.c | 8 +-- > block/blk-cgroup.h | 25 ++++----- > block/blk-throttle.c | 8 +-- Block bits look good to me. Acked-by: Vivek Goyal Vivek