On Wed, Jan 17 2018 at 2:45pm -0500, Bart Van Assche <Bart.VanAssche@xxxxxxx> wrote: > On Wed, 2018-01-17 at 14:36 -0500, Mike Snitzer wrote: > > That tree doesn't have the revert you think it does (because it doesn't have _any_ of the dm-4.16 changes). > > > > So there is some other reason for your hang. > > Hello Mike, > > Please have another look, namely at the following commit: > https://github.com/bvanassche/linux/commit/cd0b6b9f8779a0b692b1ef1d1f5ba6cb2fd981c5 > > That contents of that commit is as follows: > > Subject: [PATCH] Revert "dm rq: Avoid that request processing stalls sporadically" > > This reverts commit 6077c2d706097c00d8f2fed57d3f3c45cd228ee8. > --- > drivers/md/dm-rq.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c > index 85d80b8ccc33..a9e0f6ec62b6 100644 > --- a/drivers/md/dm-rq.c > +++ b/drivers/md/dm-rq.c > @@ -773,7 +773,6 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, > /* Undo dm_start_request() before requeuing */ > rq_end_stats(md, rq); > rq_completed(md, rq_data_dir(rq), false); > - blk_mq_delay_run_hw_queue(hctx, 100/*ms*/); > return BLK_STS_RESOURCE; > } > Fine, the chrome browser on my phone displayed "master" rather than your other branch. BUT my broader point stands: you aren't testing the dm-4.16 changes. By just reverting that commit you're creating a self-fulfilling prophecy (that you'll see hangs without it). Fact is you should pull all of dm-4.16 in, see: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-4.16 But these dm-4.16 changes are particularly important: 050af08ffb1b dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure 459b54019cfe dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIRED ec3eaf9a6731 dm mpath: don't call blk_mq_delay_run_hw_queue() in case of BLK_STS_RESOURCE 4dd6edd23e7e dm mpath: delay the retry of a request if the target responded as busy This last one is the commit that _should_ serve as a proper replacement for the change you manually reverted in your branch. Please re-test after pulling in dm-4.16 and let us know how things fair. Thanks! Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
