Messages in this thread | | | Date | Tue, 4 Aug 2009 14:01:39 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 6/6] Makes procs file writable to move all threads by tgid at once |
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Quoting Paul Menage (menage@google.com): > On Mon, Aug 3, 2009 at 12:45 PM, Serge E. Hallyn<serue@us.ibm.com> wrote: > > > > This is probably a stupid idea, but... what about having zero > > overhead at clone(), and instead, at cgroup_task_migrate(), > > dequeue_task()ing all of the affected threads for the duration of > > the migrate? > > > > Or a simpler alternative - rather than taking the thread group > leader's rwsem in cgroup_fork(), always take current's rwsem. Then > you're always locking a (probably?) local rwsem and minimizing the > overhead. So not quite zero overhead in the fork path, but I'd be > surprised if it was measurable. In cgroup_attach_proc() you then have > to take the rwsem of every thread in the process. Kind of the > equivalent of a per-threadgroup big-reader lock. > > Paul
Yup I think that would addres my concern (cache-line bouncing in hot clone(CLONE_THREAD) case).
thanks, -serge -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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