From mboxrd@z Thu Jan 1 00:00:00 1970 From: jacob pan Subject: Re: [PATCH, v3 2/2] cgroups: introduce timer slack subsystem Date: Wed, 2 Feb 2011 14:56:05 -0800 Message-ID: <20110202145605.6c9006fa__13915.6889440075$1296688400$gmane$org@putvin> References: <1296679656-31163-1-git-send-email-kirill@shutemov.name> <1296679656-31163-3-git-send-email-kirill@shutemov.name> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1296679656-31163-3-git-send-email-kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org> 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: "Kirill A. Shutsemov" Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Paul Menage , Arjan van de Ven List-Id: containers.vger.kernel.org On Wed, 2 Feb 2011 22:47:36 +0200 "Kirill A. Shutsemov" wrote: > From: Kirill A. Shutemov > > Provides a way of tasks grouping by timer slack value. Introduces per > cgroup max and min timer slack value. When a task attaches to a > cgroup, its timer slack value adjusts (if needed) to fit min-max > range. > > It also provides a way to set timer slack value for all tasks in the > cgroup at once. > > This functionality is useful in mobile devices where certain > background apps are attached to a cgroup and minimum wakeups are > desired. > > Signed-off-by: Kirill A. Shutemov > Idea-by: Jacob Pan > --- > include/linux/cgroup_subsys.h | 6 + > include/linux/init_task.h | 4 +- > init/Kconfig | 10 ++ > kernel/Makefile | 1 + > kernel/cgroup_timer_slack.c | 242 > +++++++++++++++++++++++++++++++++++++++++ > + > +static int cgroup_timer_slack_check(struct task_struct *task, > + unsigned long slack_ns) > +{ > + struct cgroup_subsys_state *css; > + struct timer_slack_cgroup *tslack_cgroup; > + use rcu_read_lock()/unlock? lockdep complains unprotected rcu dereference check. > + css = task_subsys_state(task, timer_slack_subsys.subsys_id); > + tslack_cgroup = container_of(css, struct timer_slack_cgroup, > css); + > + if (slack_ns < tslack_cgroup->min_slack_ns) > + return -EPERM; > + if (slack_ns > tslack_cgroup->max_slack_ns) > + return -EPERM; > + return 0; > +} > + > + > +static struct cftype files[] = { > + { > + .name = "set_slack_ns", > + .write_u64 = tslack_write_set_slack_ns, > + }, should we also allow reading of the current slack_ns? > + { > + .name = "min_slack_ns", > + .private = TIMER_SLACK_MIN, > + .read_u64 = tslack_read_range, > + .write_u64 = tslack_write_range, > + }, > + { > + .name = "max_slack_ns", > + .private = TIMER_SLACK_MAX, > + .read_u64 = tslack_read_range, > + .write_u64 = tslack_write_range, > + }, > +}; > +