Hi Dan, On Tue, Jan 23, 2024 at 1:53 PM Dan Moulding <dan@xxxxxxxx> wrote: > > > I think we still want d6e035aad6c0 in 6.7.2. We may need to revert > > 0de40f76d567 on top of that. Could you please test it out? (6.7.1 + > > d6e035aad6c0 + revert 0de40f76d567. > > I was operating under the assumption that the two commits were > intended to exist as a pair (the one reverts the old fix, because the > next commit has what is supposed to be a better fix). But since the > regression still exists, even with both patches applied, the old fix > must be reapplied to resolve the current regression. > > But, as you've requested, I have tested 6.7.1 + d6e035aad6c0 + revert > 0de40f76d567 and it seems fine. So I have no issue if you think it > makes sense to accept d6e035aad6c0 on its own, even though it would > break up the pair of commits. Thanks for running the test! > > > OTOH, I am not able to reproduce the issue. Could you please help > > get more information: > > cat /proc/mdstat > > Here is /proc/mdstat from one of the systems where I can reproduce it: > > $ cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] > md0 : active raid5 dm-0[4](J) sdc[3] sda[0] sdb[1] > 3906764800 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU] > > unused devices: <none> > > dm-0 is an LVM logical volume which is backed by an NVMe SSD. The > others are run-of-the-mill SATA SSDs. > > > profile (perf, etc.) of the md thread > > I might need a little more pointing in the direction of what exactly > to look for and under what conditions (i.e. should I run perf while > the thread is stuck in the 100% CPU loop? what kind of report should I > ask perf for?). Also, are there any debug options I could enable in > the kernel configuration that might help gather more information? > Maybe something in debugfs? I currently get absolutely no warnings or > errors in dmesg when the problem occurs. This appears the md thread hit some infinite loop, so I would like to know what it is doing. We can probably get the information with the perf tool, something like: perf record -a perf report Thanks, Song
