Re: [PATCH v5 07/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context

2013-02-10 Thread Srivatsa S. Bhat
Hi Namhyung, On 01/29/2013 03:51 PM, Namhyung Kim wrote: > Hi Srivatsa, > > On Tue, 22 Jan 2013 13:04:54 +0530, Srivatsa S. Bhat wrote: >> @@ -246,15 +291,21 @@ struct take_cpu_down_param { >> static int __ref take_cpu_down(void *_param) >> { >> struct take_cpu_down_param *param = _param;

Re: [PATCH v5 07/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context

2013-02-08 Thread Paul E. McKenney
On Tue, Jan 22, 2013 at 01:04:54PM +0530, Srivatsa S. Bhat wrote: > There are places where preempt_disable() or local_irq_disable() are used > to prevent any CPU from going offline during the critical section. Let us > call them as "atomic hotplug readers" ("atomic" because they run in atomic, > no

Re: [PATCH v5 07/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context

2013-01-29 Thread Namhyung Kim
Hi Srivatsa, On Tue, 22 Jan 2013 13:04:54 +0530, Srivatsa S. Bhat wrote: > @@ -246,15 +291,21 @@ struct take_cpu_down_param { > static int __ref take_cpu_down(void *_param) > { > struct take_cpu_down_param *param = _param; > - int err; > + unsigned long flags; > + int err = 0;

[PATCH v5 07/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context

2013-01-21 Thread Srivatsa S. Bhat
There are places where preempt_disable() or local_irq_disable() are used to prevent any CPU from going offline during the critical section. Let us call them as "atomic hotplug readers" ("atomic" because they run in atomic, non-preemptible contexts). Today, preempt_disable() or its equivalent works