Re: [PATCH v4 0/6] Avoid that scsi-mq and dm-mq queue processing stalls sporadically

[Bart Van Assche <Bart.VanAssche@sandisk.com>]

On Fri, 2017-04-07 at 11:33 -0700, Bart Van Assche wrote:
> On Fri, 2017-04-07 at 12:23 -0600, Jens Axboe wrote:
> > On 04/07/2017 12:16 PM, Bart Van Assche wrote:
> > > Hello Jens,
> > >=20
> > > The six patches in this patch series fix the queue lockup I reported
> > > recently on the linux-block mailing list. Please consider these patch=
es
> > > for inclusion in the upstream kernel.
> >=20
> > Some of this we need in 4.11, but not all of it. I can't be applying pa=
tches
> > that "improve scalability" at this point.
> >=20
> > 4-6 looks like what we want for 4.11, I'll see if those apply directly.=
 Then
> > we can put 1-3 on top in 4.12, with the others pulled in first.
>=20
> Hello Jens,
>=20
> Please note that patch 2/6 is a bug fix. The current implementation of
> blk_mq_sched_restart_queues() only considers hardware queues associated w=
ith
> the same request queue as the hardware queue that has been passed as an
> argument. If a tag set is shared across request queues - as is the case f=
or
> SCSI - then all request queues that share a tag set with the hctx argumen=
t
> must be considered.

(replying to my own e-mail)

Hello Jens,

If you want I can split that patch into two patches - one that runs all har=
dware
queues with which the tag set is shared and one that switches from rerunnin=
g
all hardware queues to one hardware queue.

Bart.=