On Wed, Sep 27, 2017 at 2:02 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > On 27/09/17 02:42, Linus Walleij wrote: >> On Fri, Sep 22, 2017 at 2:36 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: >> >>> Until mmc has blk-mq support fully implemented and tested, add a >>> parameter use_blk_mq, default to false unless config option MMC_MQ_DEFAULT >>> is selected. >>> >>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> >> >>> +config MMC_MQ_DEFAULT >>> + bool "MMC: use blk-mq I/O path by default" >>> + depends on MMC && BLOCK >> >> I would say: >> default y >> >> Why not. SCSI is starting to enable this by default so IMO we should > > SCSI didn't manage it yet. > >> not take the >> intermediate step of having this as optional. Otherwise it never gets tested. > > The argument that we don't have to take any responsibility for getting > things tested is a poor one. > > Anyway, you can always send a patch later to change the default, so why the > hurry to do it now? I think it should be the default so we smoke out bugs by throwing it at users during the -rc phase and the non-mq path should be the fallback. The -rc phase is for finding problems like this IMO. It is partly a personality trait I guess, I'm not very cautious in general, for good and for bad. >>> +module_param_named(use_blk_mq, mmc_use_blk_mq, bool, S_IWUSR | S_IRUGO); >> >> Are people really modprobing this so it needs to be a module parameter? > > Irrespective of modprobe, the parameter can be changed without re-compiling. > >> >> Maybe I'm the only developer stupid enough to just recompile and reboot > > Just change the parameter and unbind and rebind the host controller. Ah clever. I don't do such things, I guess I should try it out. Yours, Linus Walleij
