Re: [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node

[Alexander Duyck]

On 9/26/2018 2:53 PM, Tejun Heo wrote:
> Hello,
>
> On Wed, Sep 26, 2018 at 02:51:38PM -0700, Alexander Duyck wrote:
> > This patch provides a new function queue_work_near which is meant to
> > schedule work on the nearest unbound CPU to the requested NUMA node. The
> > main motivation for this is to help assist asynchronous init to better
> > improve boot times for devices that are local to a specific node.
> >
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
>
> Why not just use unbound workqueues, which are NUMA-affine by default?
> Are there big enough advantages?
>
> Thanks.

I am using unbound workqueues. However there isn't an interface that 
exposes the NUMA bits of them directly. All I am doing with this patch 
is adding "queue_work_near" which takes a NUMA node as an argument and 
then copies the logic of "queue_work_on" with the exception that I am 
doing a check to verify that there is an intersection between 
wq_unbound_cpumask and the cpumask of the node, and then passing a CPU 
from that intersection into "__queue_work".

Thanks.

- Alex