Messages in this thread | | | Date | Thu, 10 Oct 2013 09:43:55 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 0/6] Optimize the cpu hotplug locking -v2 |
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On Thu, 10 Oct 2013 12:36:31 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 10 Oct 2013 09:00:44 -0700 > Andrew Morton <akpm@linux-foundation.org> wrote: > > > It's been ages since I looked at this stuff :( Although it isn't used > > much, memory hotplug manages to use stop_machine() on the add/remove > > (ie, "writer") side and nothing at all on the "reader" side. Is there > > anything which fundamentally prevents cpu hotplug from doing the same? > > > I would think that memory hotplug may require stop machine as all CPUs > may touch that memory.
Sure.
> But we would like to remove stomp machine from > CPU hotplug.
We do? That's news. It wasn't mentioned in the changelog and should have been. Why?
> Why prevent all CPUs from running when we want to remove > one?
So get_online_cpus() goes away. Nothing is more scalable than nothing!
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