On Thu, 2018-01-18 at 16:23 -0500, Mike Snitzer wrote: > On Thu, Jan 18 2018 at 3:58P -0500, > Bart Van Assche <Bart.VanAssche@xxxxxxx> wrote: > > > On Thu, 2018-01-18 at 15:48 -0500, Mike Snitzer wrote: > > > For Bart's test the underlying scsi-mq driver is what is > > > regularly > > > hitting this case in __blk_mq_try_issue_directly(): > > > > > > if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) > > > > Hello Mike, > > > > That code path is not the code path that triggered the lockups that > > I reported > > during the past days. > > If you're hitting blk_mq_sched_insert_request() then you most > certainly > are hitting that code path. > > If you aren't then what was your earlier email going on about? > https://www.redhat.com/archives/dm-devel/2018-January/msg00372.html > > If you were just focusing on that as one possible reason, that isn't > very helpful. By this point you really should _know_ what is > triggering > the stall based on the code paths taken. Please use ftrace's > function_graph tracer if need be. > > > These lockups were all triggered by incorrect handling of > > .queue_rq() returning BLK_STS_RESOURCE. > > Please be precise, dm_mq_queue_rq()'s return of BLK_STS_RESOURCE? > "Incorrect" because it no longer runs blk_mq_delay_run_hw_queue()? > > Please try to do more work analyzing the test case that only you can > easily run (due to srp_test being a PITA). And less time lobbying > for > a change that you don't understand to _really_ be correct. > > We have time to get this right, please stop hyperventilating about > "regressions". > > Thanks, > Mike Hello Bart I have run a good few loops of 02-mq and its stable for me on your tree. I am not running the entire disconnect re-connect loops and un-mounts etc. for good reason. I have 35 LUNS so its very impact-full to lose them and have them come back all the time. Anyway I am very happy to try reproduce this in-house so Mike and Ming can focus on it but I need to know if all I need to do is loop over 02-mq over and over. Also please let me know whats debugfs and sysfs to capture and I am happy to try help move this along. Regards Laurence
