On 03/10/2017 07:21 AM, Adrian Hunter wrote: >> Essentially I take out that thread and replace it with this one worker >> introduced in this very patch. I agree the driver can block in many ways >> and that is why I need to have it running in process context, and this >> is what the worker introduced here provides. > > The last time I looked at the blk-mq I/O scheduler code, it pulled up to > qdepth requests from the I/O scheduler and left them on a local list while > running ->queue_rq(). That means blocking in ->queue_rq() leaves some > number of requests in limbo (not issued but also not in the I/O scheduler) > for that time. Look again, if we're not handling the requeued dispatches, we pull one at the time from the scheduler. -- Jens Axboe
