On Mon, Jul 2, 2018 at 9:03 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Mon, Jul 02, 2018 at 02:56:52PM +0200, Johannes Thumshirn wrote: >> On Mon, Jul 02, 2018 at 05:54:22AM -0700, Christoph Hellwig wrote: >> > On Mon, Jul 02, 2018 at 01:06:42PM +0800, Ming Lei wrote: >> > > With the introduced module parameter of 'use_blk_mq', it is easy >> > > to switch between 'blk_mq' and 'non_blk_mq' by reloading scsi_debug >> > > module, so that we can test scsi_mq/blk_mq related regressions easily. >> > >> > No. We should not make a per driver choice. >> >> Btw, wouldn't it be time for: >> >> diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig >> index 35c909bbf8ba..bd115bab162e 100644 >> --- a/drivers/scsi/Kconfig >> +++ b/drivers/scsi/Kconfig >> @@ -49,6 +49,7 @@ config SCSI_NETLINK >> >> config SCSI_MQ_DEFAULT >> bool "SCSI: use blk-mq I/O path by default" >> + default y >> depends on SCSI >> ---help--- >> This option enables the new blk-mq based I/O path for SCSI >> >> again and see how we've improved in the last year and a half? > > Yes, totally. We'll just need to sort out the error handling with > scsi and mq first (for 4.18 in fact). IMO, this two aren't contradictory, or not related, because this patch's motivation is for doing scsi_mq/blk_mq regression test. thanks, Ming Lei