On 03/31/2015 11:43 AM, Jens Axboe wrote:
That'd be easy enough to do, that's how blk-mq handles offline CPUs as
well. The attached patch is completely untested, but will handle offline
or nohz CPUs in the same fashion - they will punt to hardware queue 0,
which is mapped to CPU0 (and others, depending on the queue vs CPU ratio).
I have done some sanity testing with your patch,
starting a KVM guest with vcpus and emulator threads
all pinned to nohz_full cpus.
The guest is still able to do disk IO, so things
appear to work...
Thanks for looking into this, Jens.
Tested-by: Rik van Riel <riel@xxxxxxxxxx>