Messages in this thread | | | Date | Tue, 9 Aug 2011 20:19:47 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 7/8] cgroups: Add a task counter subsystem |
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On 08/09, Frederic Weisbecker wrote: > > On Tue, Aug 09, 2011 at 07:57:08PM +0200, Oleg Nesterov wrote: > > > > cgroup_attach_proc() is different, it calls cgroup_task_migrate() > > > > after ->attach_task(). Cough. > > > > > > That's bad. I need to fix that. > > > > > > So if it returns -ESRCH, I shall not call attach_task() on it > > > but cancel_attach_task(). > > > > Afaics this can't help, or I misunderstood. probably attach_task() > > can check PF_EXITING... > > But cgroup_task_migrate() checks that already before migrating > cgroups (checks PF_EXITING under task_lock() so that it's > synchronized against cgroup_exit())
Yes, but how this can help?
->attach_task() is called before cgroup_task_migrate(). Suppose that it exits before ->attach_task(). In this case we shouldn't uncharge the old cgroup, it was already uncharged by cgroup_exit.
Oleg.
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