[PATCH 3/4] workqueue: introduce helper workqueue_unbound_affinity_scope()

[Hannes Reinecke]

On 7/3/24 19:31, Tejun Heo wrote:
> Hello, Hannes.
> 
> On Wed, Jul 03, 2024 at 03:50:20PM +0200, Hannes Reinecke wrote:
>> For drivers creating their own workqueue it might be useful to
>> switch to the 'cpu' unbound affinity scope to keep the locality
>> and reduce contention. As it's cumbersome to instruct the user
>> how to switch to affinity scope from userland introduce a helper
>> workqueue_unbound_affinity_scope() to let the driver set the
>> affinity scope directly.
> 
> So, there's already apply_workqueue_attrs() to change the unbound workqueue
> attributes including affinity scope. It's cumbersome to use because the
> attribute structure has to be allocated and then freed. The alloc/free is
> for the cpumasks, so if the API is too cumbersome, maybe we can just make
> the cpumask part optional? ie. Allow using workqueue_attrs without going
> through alloc if cpumasks don't need to be modified. There probably should
> be a function to read attrs from a workqueue too.
> 
Sure; it would be ideal if one could allocate the attributes on stack, 
and then just call 'apply_workqueue_attrs()'.
And if the attrs don't include a cpumask then just leave it unchanged.
Let me see...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
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