Messages in this thread |  | | | Date | Tue, 4 Aug 2009 11:48:57 -0700 | | Subject | Re: [PATCH 6/6] Makes procs file writable to move all threads by tgid at once | | From | Paul Menage <> |
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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.
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