Ming Lei - 25.09.17, 10:59: > 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? Yes. But *additionally*, as I explained, the hangs only occured with CONFIG_HZ=1000, Low latency + CPU optimized kernel, not with CONFIG_HZ=250, voluntary preemption + generic x86 kernel. This hints a timing issue for me. So blk-mq + BFQ + CONFIG_HZ=1000 + Low Latency + CPU optimization = hang. I did not investigate whether blk-mq without scheduler would work. And I did not investigate which of the three changes to the kernel configurations triggers the issue. I suspect its either CONFIG_HZ or the preemption option or both of them. My original mail had both working and non working kernel configurations attached. Thanks, -- Martin -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
