Re: I/O hangs after resuming from suspend-to-ram

Ming Lei
2017-09-25T02:59:40Z

On Sun, Sep 24, 2017 at 07:33:00PM +0200, Martin Steigerwald wrote:
> Ming Lei - 21.09.17, 06:17:
> > On Wed, Sep 20, 2017 at 07:25:02PM +0200, Martin Steigerwald wrote:
> > > Ming Lei - 28.08.17, 21:32:
> > > > On Mon, Aug 28, 2017 at 03:10:35PM +0200, Martin Steigerwald wrote:
> > > > > Ming Lei - 28.08.17, 20:58:
> > > > > > On Sun, Aug 27, 2017 at 09:43:52AM +0200, Oleksandr Natalenko wrote:
> > > > > > > Hi.
> > >
> > > > > > > Here is disk setup for QEMU VM:
> > > […]
> > >
> > > > > > > In words: 2 virtual disks, RAID10 setup with far-2 layout, LUKS on
> > > > > > > it,
> > > > > > > then
> > > > > > > LVM, then ext4 for boot, swap and btrfs for /.
> > > > > > >
> > > > > > > I couldn't reproduce the issue with single disk without RAID.
> > > > > >
> > > > > > Could you verify if the following patch fixes your issue?
> > > > >
> > > > > Could this also apply to non MD RAID systems? I am using BTRFS RAID
> > > > > 1 with two SSDs. So far with CFQ it runs stable.
> > > >
> > > > It is for fixing Oleksandr's issue wrt. blk-mq, and looks not for you.
> > >
> > > My findings are different:
> > >
> > > On 4.12.10 with CONFIG_HZ=1000, CONFIG_PREEMPT=y and optimizations for
> > > Intel Core/newer Xeon I see this:
> > >
> > > 1) Running with CFQ: No hang after resume
> > >
> > > 2) Running with scsi_mod.use_blk_mq=1 + BFQ: Hang after resume within
> > > first 1-2 days.
> >
> > Hi Martin,
> >
> > Thanks for your report!
> >
> > Could you test the following patchset to see if it fixes your issue?
> >
> > https://marc.info/?l=linux-block&m=150579298505484&w=2
>
> Testing with https://github.com/ming1/linux.git, my_v4.13-safe-scsi-
> quiesce_V5_for_test branch as of 53954fd58fb9fe6894b1635dad1acec96ca51a2f I
> now have a bit more than three days and 8 hours of uptime without a hang on
> resume from memory or disk, despite using blk-mq + BFQ.
>
> So it looks like this patch set fixes the issue for me. To say for sure I´d say
> some more days of testing are needed. But it looks like the hang on resume is
> fixed by this patch set.

Martin, thanks for your test, it is great to see your issue is fixed
by this patchset.

Also I remember that your issue wasn't related with MD, and actually
you were using BTRFS(RAID), just want to double check with you,
is that true?

--
Ming