Re: [PATCH 3/3] pids: Make it possible to clone tasks with givenpids

[Tejun Heo]

On Fri, Nov 11, 2011 at 08:18:19PM +0400, Pavel Emelyanov wrote:
> > To add a bit, it's also one of the more *serialized* path. Doing it in
> > parallel might actually hurt, 
> 
> Can you elaborate on this, please?

It goes through a lot of locks - tasklist_lock, mmlist_lock, other
subsys locks depending on CLONE_* options.  If you try to do that on
multiple CPUs in parallel, depending on the level of concurrency,
contention and extra cacheline bounces may dominate the overhead.

Thanks.

-- 
tejun
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