On Wed, Aug 7, 2019 at 2:35 PM Jinpu Wang <jinpu.wang@xxxxxxxxxxxxxxx> wrote: > > On Wed, Aug 7, 2019 at 8:36 AM Jinpu Wang <jinpu.wang@xxxxxxxxxxxxxxx> wrote: > > > > On Wed, Aug 7, 2019 at 1:40 AM NeilBrown <neilb@xxxxxxxx> wrote: > > > > > > On Tue, Aug 06 2019, Jinpu Wang wrote: > > > > > > > On Tue, Aug 6, 2019 at 9:54 AM Jinpu Wang <jinpu.wang@xxxxxxxxxxxxxxx> wrote: > > > >> > > > >> On Tue, Aug 6, 2019 at 1:46 AM NeilBrown <neilb@xxxxxxxx> wrote: > > > >> > > > > >> > On Mon, Aug 05 2019, Jinpu Wang wrote: > > > >> > > > > >> > > Hi Neil, > > > >> > > > > > >> > > For the md higher write IO latency problem, I bisected it to these commits: > > > >> > > > > > >> > > 4ad23a97 MD: use per-cpu counter for writes_pending > > > >> > > 210f7cd percpu-refcount: support synchronous switch to atomic mode. > > > >> > > > > > >> > > Do you maybe have an idea? How can we fix it? > > > >> > > > > >> > Hmmm.... not sure. > > > >> Hi Neil, > > > >> > > > >> Thanks for reply, detailed result in line. > > > > > > Thanks for the extra testing. > > > ... > > > > [ 105.133299] md md0 in_sync is 0, sb_flags 2, recovery 3, external > > > > 0, safemode 0, recovery_cp 524288 > > > ... > > > > > > ahh - the resync was still happening. That explains why set_in_sync() > > > is being called so often. If you wait for sync to complete (or create > > > the array with --assume-clean) you should see more normal behaviour. > > I've updated my tests accordingly, thanks for the hint. > > > > > > This patch should fix it. I think we can do better but it would be more > > > complex so no suitable for backports to -stable. > > > > > > Once you confirm it works, I'll send it upstream with a > > > Reported-and-Tested-by from you. > > > > > > Thanks, > > > NeilBrown > > > > Thanks a lot, Neil, my quick test show, yes, it fixed the problem for me. > > > > I will run more tests to be sure, will report back the test result. > Hi Neil, > > I've run our regression tests with your patch, everything works fine > as expected. > > So Reported-and-Tested-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx> > > Thank you for your quick fix. > > The patch should go to stable 4.12+ Hi Neil, I hope you're doing well, just a soft ping? do you need further testing from my side? Please let me know how can we move the fix forward. Thanks, Jack Wang
