[PATCH 5/7] cgroup_freezer: allow moving tasks in and out of a frozen cgroup
tj at kernel.org
Mon Oct 22 21:25:05 UTC 2012
On Mon, Oct 22, 2012 at 09:25:06PM +0200, Oleg Nesterov wrote:
> > @@ -190,12 +201,12 @@ static void freezer_fork(struct task_struct *task)
> > goto out;
> > spin_lock_irq(&freezer->lock);
> > - BUG_ON(freezer->state == CGROUP_FROZEN);
> > -
> > - /* Locking avoids race with FREEZING -> THAWED transitions. */
> > - if (freezer->state == CGROUP_FREEZING)
> > + /*
> > + * @task might have been just migrated into a FROZEN cgroup.
> Confused. If it was migrated, then freezer_attach() should take care
> do freeze_task?
Hmmm... there's a window where a task is migrated but ->attach()
hasn't completed yet, so freezer_attach() might not have kicked in
yet. It might not be strictly necessary but I think it's more
consistent this way. No?
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