Re: [PATCH 0/4] CPU hotplug, cpusets: Fix CPU online handling relatedto cpusets

[Srivatsa S. Bhat]

On 02/11/2012 07:37 AM, Peter Zijlstra wrote:

> On Fri, 2012-02-10 at 23:39 +0100, Rafael J. Wysocki wrote:
>>
>>> I don't see why not.  Presumably no CPUs will be added or removed while 
>>> the system is asleep.
>>
>> ACPI explicitly forbids that level of hardware reconfiguration in a sleep
>> state (even in S4), AFAICS.  Still, people may try to do that ... 
> 
> I'm ok with breaking that :-) If its really really important to someone
> we (him most likely) could fix it by detecting the topology changed over
> the suspend and do a fixup. Assuming it actually gets that far.
> 
> Srivatsa, wanna give this (the proposal to not modify cpusets on
> CPU_TASKS_FROZEN) a try?
> 


Sure! After you pointed out that CPU Hotplug is destructive in general and
hence it is not a good idea to put back online CPUs to cpusets, the next
thing I thought of trying was a special case handling for suspend/resume
alone, IOW, not calling the cpuset update upon CPU_TASKS_FROZEN.

So, yes, I'll write up a patch for that and post it soon :-)

Regards,
Srivatsa S. Bhat

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