On 10/1/2018 9:01 AM, Tejun Heo wrote:
Hello,
On Wed, Sep 26, 2018 at 03:19:21PM -0700, Alexander Duyck wrote:
On 9/26/2018 3:09 PM, Tejun Heo wrote:
I could just use queue_work_on probably, but is there any issue if I
am passing CPU values that are not in the wq_unbound_cpumask? That
That should be fine. If it can't find any available cpu, it'll fall
back to round-robin. We probably can improve it so that it can
consider the numa distance when falling back.
was mostly my concern. Also for an unbound queue do I need to worry
about the hotplug lock? I wasn't sure if that was the case or not as
Issuers don't need to worry about them.
I know it is called out as something to be concerned with using
queue_work_on, but in __queue_work the value is just used to
determine which node to grab a work queue from.
It might be better to leave queue_work_on() to be used for per-cpu
workqueues and introduce queue_work_near() as you suggseted. I just
don't want it to duplicate the node selection code in it. Would that
work?
So if I understand what you are saying correctly we default to
round-robin on a given node has no CPUs attached to it. I could probably
work with that if that is the default behavior instead of adding much of
the complexity I already have.
The question I have then is what should I do about workqueues that
aren't WQ_UNBOUND if they attempt to use queue_work_near? In that case I
should be looking for some way to go from a node to a CPU shouldn't I?
If so should I look at doing something like wq_select_unbound_cpu that
uses the node cpumask instead of the wq_unbound_cpumask?
- Alex
_______________________________________________
Linux-nvdimm mailing list
[email protected]
https://lists.01.org/mailman/listinfo/linux-nvdimm
