Re: [patch,v2] bdi: add a user-tunable cpu_list for the bdi flusher threads

Tejun Heo [off-list ref] writes:

Hello, Jens.

On Thu, Dec 06, 2012 at 07:19:34PM +0100, Jens Axboe wrote:

quoted

We need to expose it. Once the binding is set from the kernel side on a
kernel thread, it can't be modified.

That's only if kthread_bind() is used.  Caling set_cpus_allowed_ptr()
doesn't set PF_THREAD_BOUND and userland can adjust affinity like any
other tasks.

quoted

Binding either for performance reasons or for ensuring that we
explicitly don't run in some places is a very useful feature.

Sure, but I think this is too specific.  Something more generic would
be much better.  It can be as simple as generating a uevent.

I'm in favor of a more general approach.  For now, I'm still going to
push a patch that at least binds to the proper numa node.  I'll post
that after I've tested it.

Cheers,
Jeff

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