From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Brauner Subject: Re: [PATCH v2 2/3] clone3: allow spawning processes into cgroups Date: Fri, 17 Jan 2020 00:57:22 +0100 Message-ID: <20200116235721.tnadjblifqirg5bo@wittgenstein> References: <20191223061504.28716-1-christian.brauner@ubuntu.com> <20191223061504.28716-3-christian.brauner@ubuntu.com> <20200108160102.GA17415@blackbody.suse.cz> <20200108181049.ysmo73celrt4bvo2@wittgenstein> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <20200108181049.ysmo73celrt4bvo2@wittgenstein> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Michal =?utf-8?Q?Koutn=C3=BD?= Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , Ingo Molnar , Oleg Nesterov , Johannes Weiner , Li Zefan , Peter Zijlstra , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Wed, Jan 08, 2020 at 07:10:49PM +0100, Christian Brauner wrote: > On Wed, Jan 08, 2020 at 05:01:02PM +0100, Michal Koutný wrote: > > On Mon, Dec 23, 2019 at 07:15:03AM +0100, Christian Brauner wrote: > > > This adds support for creating a process in a different cgroup than its > > > parent. > > Binding fork and migration together looks useful. > > > > > --- a/kernel/cgroup/cgroup.c > > > +++ b/kernel/cgroup/cgroup.c > > > @@ -5882,21 +5882,176 @@ void cgroup_fork(struct task_struct *child) > > > INIT_LIST_HEAD(&child->cg_list); > > Just a nitpick, I noticed the comment for cgroup_fork should be updated > > too (generic migration happens in cgroup_post_fork). > > Thanks. > > > > > > --- a/kernel/fork.c > > > +++ b/kernel/fork.c > > > [...] > > > @@ -2279,8 +2278,7 @@ static __latent_entropy struct task_struct *copy_process( > > > write_unlock_irq(&tasklist_lock); > > > > > > proc_fork_connector(p); > > > - cgroup_post_fork(p); > > > - cgroup_threadgroup_change_end(current); > > > + cgroup_post_fork(current, p, args); > > I can see that when CLONE_INTO_CGROUP | CLONE_NEWCGROUP is passed, then > > the child's cgroup NS will be rooted at parent's css set > > (copy_namespaces precedes cgroup_post_fork). > > > > Wouldn't it make better sense if this flags combination resulted in > > child's NS rooted in its css set? > > I need to take a closer look but it sounds like we should move the > copying of the cgroup namespace to a later point; but again I need to > look into this. Ok, this is way simpler I think, we just set the root_cset of the new cgroup namespace to the child's cset in cgroup_post_fork() if CLONE_NEWCGROUP is requested. Christian