Re: [PATCH v4 1/2] workqueue: add new schedule_on_cpu_mask() API

From: Tejun Heo
Date: Fri Aug 09 2013 - 11:03:08 EST


Hello, Chris.

On Wed, Aug 07, 2013 at 04:49:44PM -0400, Chris Metcalf wrote:
> This primitive allows scheduling work to run on a particular set of
> cpus described by a "struct cpumask". This can be useful, for example,
> if you have a per-cpu variable that requires code execution only if the
> per-cpu variable has a certain value (for example, is a non-empty list).

So, this allows scheduling work items on !online CPUs. Workqueue does
allow scheduling per-cpu work items on offline CPUs if the CPU has
ever been online, but the behavior when scheduling work items on cpu
which has never been online is undefined. I think the interface at
least needs to verify that the the target cpus have been online,
trigger warning and mask off invalid CPUs otherwise.

Thanks.

--
tejun
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