Re: [PATCH v2] block: BFQ default for single queue devices

Linus Walleij
2018-10-19T08:42:53Z

On Wed, Oct 17, 2018 at 4:59 PM Bryan Gurney <bgurney@redhat.com> wrote:

> I feel strongly about the prevention of users running into errors
> because of an incorrect scheduler default, because I encountered that
> situation three times in my testing with zoned block devices. The
> switch to SCSI_MQ would resolve that, since mq-deadline is the
> default, but in my case, I was using Fedora 28, which disables
> CONFIG_SCSI_MQ_DEFAULT (which is enabled in the 4.18 kernel), so my
> default scheduler was cfq.

I think we should make a patch to the kernel that makes it
impossible (even from sysfs) to choose a non-zone aware
scheduler for these devices.

It's another topic than $SUBJECT patch though. I take this
into account in this version.

Yours,
Linus Walleij