On Sun, Sep 24, 2017 at 07:33:00PM +0200, Martin Steigerwald wrote:

Ming Lei - 21.09.17, 06:17:

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On Wed, Sep 20, 2017 at 07:25:02PM +0200, Martin Steigerwald wrote:

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Ming Lei - 28.08.17, 21:32:

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On Mon, Aug 28, 2017 at 03:10:35PM +0200, Martin Steigerwald wrote:

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Ming Lei - 28.08.17, 20:58:

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On Sun, Aug 27, 2017 at 09:43:52AM +0200, Oleksandr Natalenko wrote:

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Hi.

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Here is disk setup for QEMU VM:

[…]

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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