On Tue, Jul 04, 2017 at 10:56:23AM +0300, Sagi Grimberg wrote: > > > There are at least one case in which we have to use stop queues: > > > > - when QUEUE_BUSY(now it becomes BLK_STS_RESOURCE) happens, some drivers > > need to stop queues for avoiding to hurt CPU, such as virtio-blk, ... > > Why isn't virtio_blk using blk_mq_delay_run_hw_queue like scsi does? IMO it shouldn't be easy to figure out one perfect delay time, and it should have been self-adaptive. Also I think it might be possible to move this kind of stop action into blk-mq core code, and not let drivers touch stop state. Finally we may kill all stopping in drivers. Thanks, Ming
