On Mon, 25 Jul 2016 20:11:51 -0400 Tejun Heo [off-list ref] wrote:

Hello, Andrew.

On Mon, Jul 25, 2016 at 04:20:22PM -0700, Andrew Morton wrote:

quoted

quoted

When a pool workqueue is initialized, if its cpumask belongs to a node, its
pool->node will be mapped to that node. And memory used by this workqueue will
also be allocated on that node.

Plan B is to hunt down and fix up all the workqueue structures at
hotplug-time.  Has that option been evaluated?

Your fix is x86-only and this bug presumably affects other
architectures, yes?  I think a "Plan B" would fix all architectures?

Yeah, that was one of the early approaches.  The issue isn't limited
to wq.  Any memory allocation can have similar issues of underlying
node association changing and we don't have any synchronization
mechanism around it.  It doesn't make any sense to make NUMA
association dynamic when the consumer surface is vastly larger and
there's nothing inherently dynamic about the association itself.

And other architectures?

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