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From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
	Alan Stern <stern@rowland.harvard.edu>,
	paulmck@linux.vnet.ibm.com, Ingo Molnar <mingo@elte.hu>,
	paul@paulmenage.org, tj@kernel.org, frank.rowand@am.sony.com,
	pjt@google.com, tglx@linutronix.de, lizf@cn.fujitsu.com,
	prashanth@linux.vnet.ibm.com, vatsa@linux.vnet.ibm.com,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/4] CPU hotplug, cpusets: Fix CPU online handling related to cpusets
Date: Sat, 11 Feb 2012 09:56:57 +0530	[thread overview]
Message-ID: <4F35EE11.5010202@linux.vnet.ibm.com> (raw)
In-Reply-To: <1328926042.2476.3.camel@laptop>

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


  reply	other threads:[~2012-02-11  4:27 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-07 18:55 [PATCH 0/4] CPU hotplug, cpusets: Fix CPU online handling related to cpusets Srivatsa S. Bhat
2012-02-07 18:56 ` [PATCH 1/4] CPU hotplug, cpuset: Maintain a copy of the cpus_allowed mask before CPU hotplug Srivatsa S. Bhat
2012-02-07 18:56 ` [PATCH 2/4] cpuset: Split up update_cpumask() so that its functionality can be reused Srivatsa S. Bhat
2012-02-07 18:57 ` [PATCH 3/4] cpuset: Add function to introduce CPUs to cpusets during CPU online Srivatsa S. Bhat
2012-02-07 18:57 ` [PATCH 4/4] CPU hotplug, cpusets: Differentiate the CPU online and CPU offline callbacks Srivatsa S. Bhat
2012-02-08  3:22 ` [PATCH 0/4] CPU hotplug, cpusets: Fix CPU online handling related to cpusets Peter Zijlstra
2012-02-08  6:33   ` Srivatsa S. Bhat
2012-02-09  7:57     ` Ingo Molnar
2012-02-09  8:42       ` Srivatsa S. Bhat
2012-02-09 15:11         ` Ingo Molnar
2012-02-10 15:52           ` Peter Zijlstra
2012-02-10 16:53             ` Paul E. McKenney
2012-02-10 17:34               ` Peter Zijlstra
2012-02-10 21:51                 ` Alan Stern
2012-02-10 22:39                   ` Rafael J. Wysocki
2012-02-11  2:07                     ` Peter Zijlstra
2012-02-11  4:26                       ` Srivatsa S. Bhat [this message]
2012-02-13 17:47                         ` Srivatsa S. Bhat
2012-02-17 12:15                           ` Srivatsa S. Bhat
2012-02-20 12:49                             ` Peter Zijlstra
2012-02-20 12:59                               ` Srivatsa S. Bhat
2012-02-23  9:57                                 ` Srivatsa S. Bhat
2012-02-24 23:24                                   ` Rafael J. Wysocki
2012-02-27 10:18                                   ` Peter Zijlstra
2012-02-27 12:09                                   ` [tip:sched/urgent] CPU hotplug, cpusets, suspend: Don' t touch cpusets during suspend/resume tip-bot for Srivatsa S. Bhat
2012-02-11 16:00                 ` [PATCH 0/4] CPU hotplug, cpusets: Fix CPU online handling related to cpusets Paul E. McKenney
2012-02-13 17:47               ` Srivatsa S. Bhat
2012-02-13 20:39                 ` Paul E. McKenney
2012-02-13 20:49                   ` Srivatsa S. Bhat
2012-02-11 13:39             ` Ingo Molnar
2012-02-10 15:53         ` Peter Zijlstra
2012-02-09 16:43     ` Peter Zijlstra

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