Messages in this thread | | | Date | Thu, 26 Jul 2012 16:43:11 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [RFC PATCH 0/6] CPU hotplug: Reverse invocation of notifiers during CPU hotplug |
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On 07/26/2012 04:25 PM, Thomas Gleixner wrote: > On Wed, 25 Jul 2012, Srivatsa S. Bhat wrote: >> On 07/25/2012 10:00 PM, Thomas Gleixner wrote: >>> struct hotplug_event hotplug_events_bp[CPU_HOTPLUG_MAX_EVENTS]; >>> struct hotplug_event hotplug_events_ap[CPU_HOTPLUG_MAX_EVENTS]; >>> >>> The _bp one is the list of events which are executed on the active cpu >>> and the _ap ones are those executed on the hotplugged cpu. >>> >>> The core code advances the events in sync steps, so both BP and AP can >>> issue a stop on the process and cause a rollback. >> >> What exactly does "sync steps" mean in this context? Also, for the CPU > > Sync step means, that both sides need to synchronize - not at every > step, but at well defined synchronization points. You can't advance > the AP to online state unless the BP has done the preparatory stuff > already. > >> offline event, the event could start off with both the BP and the AP being >> the same CPU.. Does this design take care of that case? > > Once the AP leaves the state where tasks can be freely scheduled on > it, the take down thread migrates automagically. And that's one of the > first things I'm trying to do so the first synchronization point is > after that. >
Oh.. Ok.. Thanks for the explanation!
Regards, Srivatsa S. Bhat
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