Messages in this thread |  | | Date | Tue, 11 Feb 2014 12:31:02 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [PATCH 26/51] x86, oprofile, nmi: Fix CPU hotplug callback registration |
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On 02/11/2014 12:57 AM, Gautham R Shenoy wrote: > On Tue, Feb 11, 2014 at 12:37:37AM +0530, Gautham R Shenoy wrote: >> Hi, >> >> On Thu, Feb 06, 2014 at 03:39:22AM +0530, Srivatsa S. Bhat wrote: >>> Fix the oprofile code in x86 by using this latter form of callback >>> registration. But retain the calls to get/put_online_cpus(), since they >>> also protect the variables 'nmi_enabled' and 'ctr_running'. >> >> get/put_online_cpus() protect us against cpu_hotplug_begin/end(). The >> latter is always nested inside cpu_maps_update_begin/end(), which we >> are already using here. >> >> So what additional protection are we getting by retaining >> get/put_online_cpus() ? > > Probably you mean to say that there are other places which access > 'nmi_enabled' and 'ctr_running' with the cpu-hotplug protection > provided only by get/put_online_cpus() and you are retaining the calls > in this patch to be consistent with those other places.
Yep, exactly!
> If so, could > you reword the changelog to reflect this instead of saying "they also > protect the variables ..." ? >
Ok, will do! Thanks a lot!
Regards, Srivatsa S. Bhat
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