Messages in this thread | | | Date | Thu, 10 Oct 2013 10:13:53 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 0/6] Optimize the cpu hotplug locking -v2 |
| |
On Thu, Oct 10, 2013 at 06:50:46PM +0200, Ingo Molnar wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > > > On Thu, Oct 10, 2013 at 04:57:38PM +0200, Ingo Molnar wrote: > > > > > So ... why not make it _really_ cheap, i.e. the read lock costing > > > nothing, and tie CPU hotplug to freezing all tasks in the system? > > > > Such that we freeze regular tasks in userspace and kernel tasks in their > > special freezer callback so as to guarantee minimal state? > > Yes, absolutely.
That does add quite a bit of latency to the hotplug operations, which IIRC slows down things like boot, suspend, and resume.
Thanx, Paul
| |