Re: [PATCH] cpu_hotplug: don't affect current task's affinity
From: Lai Jiangshan
Date: Wed Jul 22 2009 - 22:06:33 EST
Andrew Morton wrote:
>
> Or are you saying that the mask _should_ have been 0-1,3 but the kernel
> incorrectly set it to "0"?
>
Yes, the mask should become 0-1,3. when original is 2 after cpu2 is offlined.
When cpu2 is offined
original mask after cpu2 is offined
1 1
1-2 1
0-3 0-1,3
2 0-1,3
2(the task who do the offline) 0
I think the last line is incorrect. This patch fix it.
>
> Also, it says "The recovery of the current tasks's cpus_allowed will
> fail under some conditions". What are those conditions?
>
A condition is described in changelog(the same as above).
An example of other condition: the CPUSET of the task is changed
when this task do the offline... the last recovery may fails.
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