Re: get/put_online_cpus documentation wrong?

[Gilad Ben-Yossef]

On Tue, May 1, 2012 at 3:12 AM, Paul Mackerras <paulus@xxxxxxxxx> wrote:
>
> In Documentation/cpu-hotplug.txt it says:
>
> "       #include <linux/cpu.h>
>        get_online_cpus() and put_online_cpus():
>
> The above calls are used to inhibit cpu hotplug operations. While the
> cpu_hotplug.refcount is non zero, the cpu_online_mask will not change.
> If you merely need to avoid cpus going away, you could also use
> preempt_disable() and preempt_enable() for those sections.
> Just remember the critical section cannot call any
> function that can sleep or schedule this process away."


I *think* the critical section remark here is referring to using
preempt_disable/enable(),
rather  then the use of get/put_online_cpus().

Gilad


--
Gilad Ben-Yossef
Chief Coffee Drinker
gilad@xxxxxxxxxxxxx
Israel Cell: +972-52-8260388
US Cell: +1-973-8260388
http://benyossef.com

"If you take a class in large-scale robotics, can you end up in a
situation where the homework eats your dog?"
 -- Jean-Baptiste Queru
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/