Re: [PATCH] block-mq: set both block queue and hardware queue restart bit for restart

[Bart Van Assche]

On Thu, 2017-04-06 at 04:21 +0000, KY Srinivasan wrote:
> > -----Original Message-----
> > From: Bart Van Assche [mailto:Bart.VanAssche@xxxxxxxxxxx]
> > Sent: Wednesday, April 5, 2017 8:46 PM
> > To: linux-kernel@xxxxxxxxxxxxxxx; linux-block@xxxxxxxxxxxxxxx; Long Li
> > <longli@xxxxxxxxxxxxx>; axboe@xxxxxxxxx
> > Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; KY Srinivasan
> > <kys@xxxxxxxxxxxxx>
> > Subject: Re: [PATCH] block-mq: set both block queue and hardware queue
> > restart bit for restart
> > 
> > On Thu, 2017-04-06 at 03:38 +0000, Long Li wrote:
> > > > -----Original Message-----
> > > > From: Bart Van Assche [mailto:Bart.VanAssche@xxxxxxxxxxx]
> > > > 
> > > > Please drop this patch. I'm working on a better solution.
> > > 
> > > Thank you. Looking forward to your patch.
> > 
> > Hello Long,
> > 
> > It would help if you could share the name of the block or SCSI driver with
> > which you ran into that lockup and also if you could share the name of the
> > I/O scheduler used in your test.
> 
> The tests that indicated the issue were run Hyper-V. The driver is storvsc_drv.c
> The I/O scheduler was I think noop.

Hello Long and K.Y.,

Thank you for the feedback. Can you repeat your test with kernel v4.11-rc6? The
patches that went into the block layer for v4.11-rc6 should be sufficient to fix
this:

$ PAGER= git log --format=short v4.11-rc5..v4.11-rc6 block include/linux/blk*  
commit 6d8c6c0f97ad8a3517c42b179c1dc8e77397d0e2
Author: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

    blk-mq: Restart a single queue if tag sets are shared

commit 7587a5ae7eef0439f7be31f1b5959af062bbc5ec
Author: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

    blk-mq: Introduce blk_mq_delay_run_hw_queue()

commit ebe8bddb6e30d7a02775b9972099271fc5910f37
Author: Omar Sandoval <osandov@xxxxxx>

    blk-mq: remap queues when adding/removing hardware queues

commit 54d5329d425650fafaf90660a139c771d2d49cae
Author: Omar Sandoval <osandov@xxxxxx>

    blk-mq-sched: fix crash in switch error path

commit 93252632e828da3e90241a1c0e766556abf71598
Author: Omar Sandoval <osandov@xxxxxx>

    blk-mq-sched: set up scheduler tags when bringing up new queues

commit 6917ff0b5bd4139e08a3f3146529dcb3b95ba7a6
Author: Omar Sandoval <osandov@xxxxxx>

    blk-mq-sched: refactor scheduler initialization

commit 81380ca10778b99dce98940cfc993214712df335
Author: Omar Sandoval <osandov@xxxxxx>

    blk-mq: use the right hctx when getting a driver tag fails

commit ac77a0c463c1d7d659861f7b6d1261970dd3282a
Author: Minchan Kim <minchan@xxxxxxxxxx>

    block: do not put mq context in blk_mq_alloc_request_hctx

Bart.