Re: [PATCH] workqueue: update numa affinity when node hotplug

Tejun Heo
2015-03-03T13:18:58Z

Hello, Kame.

On Tue, Mar 03, 2015 at 03:53:46PM +0900, Kamezawa Hiroyuki wrote:
> relationship between proximity domain and lapic id doesn't change.
> relationship between lapic-id and cpu-id changes.
>
> pxm <-> memory address : no change
> pxm <-> lapicid : no change
> pxm <-> node id : no change
> lapicid <-> cpu id : change.

So, we're changing the cpu ID to NUMA node mapping because current
NUMA code is ignoring PXM for memoryless nodes? That's it?

> >>I personally thinks proper fix is building persistent cpu-id <-> lapicid relationship as
> >>pxm does rather than creating band-aid.
> >
> >Oh if this is possible, I agree that's the right direction too.
> >
>
> Implementation is a bit complicated now :(.

Ah well, even then, the obviously right thing to do is updating NUMA
code to always keep track of PXM information. We don't really want to
pile NUMA hacks in random users of NUMA code.

Thanks.

--
tejun