Re: [PATCH 01/51] CPU hotplug: Provide lockless versions of callback registration functions

[Gautham R Shenoy]

On Mon, Feb 10, 2014 at 06:26:20PM -0700, Toshi Kani wrote:
> 
> get/put_online_cpus() is a reader-lock and concurrent executions are
> allowed among the readers.  They won't be serialized until a cpu
> online/offline operation begins.  By replacing this lock with
> cpu_maps_update_begin/done(), we now serialize all readers.

We're not serializing all the readers, just the ones which want to
register/unregister their cpu-hotplug notifiers. This is a one-off
event which typically happens during a module_init() or a
module_exit() time. So this patchset does not replace
get/put_online_cpus() if that is the concern!

--
Thanks and Regards
gautham.
 


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