From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <htejun@gmail.com>
Cc: rjw@sisk.pl, paul@paulmenage.org, lizf@cn.fujitsu.com,
linux-pm@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, fweisbec@gmail.com,
matthltc@us.ibm.com, akpm@linux-foundation.org,
Tejun Heo <tj@kernel.org>, Paul Menage <menage@google.com>
Subject: Re: [PATCH 4/4] cgroup: always lock threadgroup during migration
Date: Sun, 18 Sep 2011 19:41:17 +0200 [thread overview]
Message-ID: <20110918174117.GB2384@redhat.com> (raw)
In-Reply-To: <1315159280-25032-5-git-send-email-htejun@gmail.com>
On 09/05, Tejun Heo wrote:
>
> * Remove -ESRCH failure path from cgroup_task_migrate(). With the
> above changes, it's guaranteed to be called only for live tasks.
I think you can remove another similar check,
> @@ -2044,6 +2044,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> tsk = leader;
> i = 0;
> do {
> + /* @tsk either already exited or can't exit until the end */
> + if (tsk->flags & PF_EXITING)
> + continue;
> +
> /* as per above, nr_threads may decrease, but not increase. */
> BUG_ON(i >= group_size);
> get_task_struct(tsk);
And then cgroup_attach_proc() does
for (i = 0; i < group_size; i++) {
...
task_lock(tsk);
if (tsk->flags & PF_EXITING) {
task_unlock(tsk);
continue;
Afaics, this is no longer needed.
Oleg.
next prev parent reply other threads:[~2011-09-18 17:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-04 18:01 [PATCHSET cgroup] extend threadgroup locking Tejun Heo
2011-09-04 18:01 ` [PATCH 1/4] cgroup: change locking order in attach_task_by_pid() Tejun Heo
2011-09-18 18:56 ` Oleg Nesterov
2011-10-10 17:34 ` Tejun Heo
2011-10-10 17:43 ` Tejun Heo
2011-09-04 18:01 ` [PATCH 2/4] threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem Tejun Heo
2011-09-04 18:01 ` [PATCH 3/4] threadgroup: extend threadgroup_lock() to cover exit and exec Tejun Heo
2011-09-12 4:04 ` Paul Menage
2011-09-13 7:54 ` Tejun Heo
2011-09-18 17:37 ` Oleg Nesterov
2011-09-18 18:46 ` Oleg Nesterov
2011-10-08 18:37 ` Ben Blum
2011-10-10 17:11 ` Tejun Heo
2011-10-12 17:51 ` Oleg Nesterov
2011-10-12 18:05 ` Ben Blum
2011-10-12 18:29 ` Oleg Nesterov
2011-10-12 18:44 ` Ben Blum
2011-10-12 19:07 ` Oleg Nesterov
2011-09-04 18:01 ` [PATCH 4/4] cgroup: always lock threadgroup during migration Tejun Heo
2011-09-18 17:41 ` Oleg Nesterov [this message]
2011-10-10 17:31 ` Tejun Heo
2011-09-05 4:05 ` [PATCHSET cgroup] extend threadgroup locking Rafael J. Wysocki
2011-09-05 8:43 ` Tejun Heo
2011-09-06 9:00 ` Li Zefan
2011-09-11 3:35 ` Tejun Heo
2011-09-14 18:33 ` Oleg Nesterov
2011-09-14 23:33 ` Tejun Heo
2011-09-12 4:11 ` Paul Menage
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