From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH 6/8] cgroup: remove cgroup->name Date: Wed, 29 Jan 2014 13:09:07 +0100 Message-ID: <20140129120907.GA22183@dhcp22.suse.cz> References: <1390953585-16554-1-git-send-email-tj@kernel.org> <1390953585-16554-7-git-send-email-tj@kernel.org> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1390953585-16554-7-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tejun Heo Cc: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Peter Zijlstra , Ingo Molnar , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki On Tue 28-01-14 18:59:43, Tejun Heo wrote: > cgroup->name handling became quite complicated over time involving > dedicated struct cgroup_name for RCU protection. Now that cgroup is > on kernfs, we can drop all of it and simply use kernfs_name/path() and > friends. Replace cgroup->name and all related code with kernfs > name/path constructs. > > * Reimplement cgroup_name() and cgroup_path() as thin wrappers on top > of kernfs counterparts, which involves semantic changes. > pr_cont_cgroup_name() and pr_cont_cgroup_path() added. > > * cgroup->name handling dropped from cgroup_rename(). > > * All users of cgroup_name/path() updated to the new semantics. Users > which were formatting the string just to printk them are converted > to use pr_cont_cgroup_name/path() instead, which simplifies things > quite a bit. As cgroup_name() no longer requires RCU read lock > around it, RCU lockings which were protecting only cgroup_name() are > removed. > > Signed-off-by: Tejun Heo > Cc: Li Zefan > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Balbir Singh > Cc: KAMEZAWA Hiroyuki Nice. I hated the way how we retrieved the name previously. Acked-by: Michal Hocko Btw. after this change we should drop part of the comment above oom_info_lock: diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 19d5d4274e22..d998baec5deb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1684,8 +1684,7 @@ static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) { /* - * protects memcg_name and makes sure that parallel ooms do not - * interleave + * Makes sure that parallel ooms do not interleave */ static DEFINE_SPINLOCK(oom_info_lock); struct cgroup *task_cgrp; -- Michal Hocko SUSE Labs