On 1/21/20 12:25 PM, muraliraja.muniraju wrote:

Current loop device implementation has a single kthread worker and
drains one request at a time to completion. If the underneath device is
slow then this reduces the concurrency significantly. To help in these
cases, adding multiple loop workers increases the concurrency. Also to
retain the old behaviour the default number of loop workers is 1 and can
be tuned via the ioctl.

Have you considered using blk-mq for this? Right now loop just does
some basic checks and then queues for a thread. If you bump nr_hw_queues
up (provide a parameter for that) and set BLK_MQ_F_BLOCKING in the
tag flags, then that might be a more viable approach for handling this.

-- 
Jens Axboe