On Mon, Jan 29, 2018 at 03:40:31PM -0500, Mike Snitzer wrote: > On Mon, Jan 29 2018 at 10:46am -0500, > Ming Lei <ming.lei@xxxxxxxxxx> wrote: > > > 2. When to enable SCSI_MQ at default again? > > > > SCSI_MQ is enabled on V3.17 firstly, but disabled at default. In V4.13-rc1, > > it is enabled at default, but later the patch is reverted in V4.13-rc7, and > > becomes disabled at default too. > > > > Now both the original reported PM issue(actually SCSI quiesce) and the > > sequential IO performance issue have been addressed. And MQ IO schedulers > > are ready too for traditional disks. Are there other issues to be addressed > > for enabling SCSI_MQ at default? When can we do that again? > > > > Last time, the two issues were reported during V4.13 dev cycle just when it is > > enabled at default, that seems if SCSI_MQ isn't enabled at default, it wouldn't > > be exposed to run/tested completely & fully. > > > > So if we continue to disable it at default, maybe it can never be exposed to > > full test/production environment. > > I was going to propose revisiting this as well. > > I'd really like to see all the old .request_fn block core code removed. Yeah, that should be a final goal, but may take a bit long. > > But maybe we take a first step of enabling: > CONFIG_SCSI_MQ_DEFAULT=Y > CONFIG_DM_MQ_DEFAULT=Y Maybe you can remove legacy path from DM_RQ first, and take your original approach to allow DM/MQ over legacy underlying driver, seems we discussed this topic before, :-) Thanks, Ming
