[RFC PATCH] ARM: smp: Fix the CPU hotplug race with scheduler.

[sboyd@codeaurora.org (Stephen Boyd)]

On 06/21/2011 04:10 PM, Russell King - ARM Linux wrote:
> On Tue, Jun 21, 2011 at 01:16:47PM -0700, Stephen Boyd wrote:
>> On 06/21/2011 03:26 AM, Russell King - ARM Linux wrote:
>>> On Tue, Jun 21, 2011 at 03:51:00PM +0530, Santosh Shilimkar wrote:
>>>> On 6/21/2011 3:49 PM, Russell King - ARM Linux wrote:
>>>>> I won't be committing the init/calibrate.c change to a git tree - it
>>>>> isn't ARM stuff so it goes in patch form.
>>>> Patches with change log would be fine as well.
>>> The answer is not at the moment, but maybe soon.
>> Should we send those two patches to the stable trees as well? They seem
>> to fix issues with cpu onlining that have existed for a long time.
> Looks to me like the problem was introduced for 2.6.39-rc1, so we
> should probably get the fix into the 2.6.39-stable tree too.

Are we talking about the loops_per_jiffy problem or the cpu_active
problem? I would think the cpu_active problem has been there since SMP
support was added to ARM and the loops_per_jiffy problem has been there
(depending on the compiler) since 8a9e1b0 ([PATCH] Platform SMIs and
their interferance with tsc based delay calibration, 2005-06-23).

So pretty much every stable tree would want both of these patches.

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