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? > I forgot to address your question about the advantages. They are > pretty significant. The test system I was working with was > initializing 3TB of nvdimm memory per node. If the node is aligned > it takes something like 24 seconds, whereas an unaligned core can > take 36 seconds or more. Oh yeah, sure, numa affinity matters quite a bit on memory heavy workloads. I was mistaken that you were adding adding numa affinity to per-cpu workqueues. Thanks. -- tejun _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
