[PATCH 0/4] workqueue: fix bug when numa mapping is changed v2.

Kamezawa Hiroyuki
2014-12-13T16:34:28Z

Yasuaki Ishimatsu hit a allocation failure bug when the numa mapping
between CPU and node is changed. This was the last scene:
SLUB: Unable to allocate memory on node 2 (gfp=0x80d0)
cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0
node 0: slabs: 6172, objs: 259224, free: 245741
node 1: slabs: 3261, objs: 136962, free: 127656

I and Yasuaki have a host which has a feature of node hotplug, this is a fix by me.
Tested several patterns of hotplug and I found no issue, now.
Of course I read Lai's patch and Tejun's comment. I hope I could reflect them.

1/4 ... add node-hotplug event callback.
2/4 ... add a sanity check (for debug)
3/4 ... remove per-node unbound workqueue if node goes offline.
4/4 ... update per-cpu pool's information and cpumasks, node information
based on the latest (cpu, node) information.

Thanks,
-Kame