From: Mike Snitzer <snitzer@redhat.com> To: Bart Van Assche <Bart.VanAssche@wdc.com> Cc: "axboe@kernel.dk" <axboe@kernel.dk>, "dm-devel@redhat.com" <dm-devel@redhat.com>, "hch@infradead.org" <hch@infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "osandov@fb.com" <osandov@fb.com>, "ming.lei@redhat.com" <ming.lei@redhat.com> Subject: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Date: Thu, 18 Jan 2018 16:23:27 -0500 [thread overview] Message-ID: <20180118212327.GB31679@redhat.com> (raw) In-Reply-To: <1516309128.2676.38.camel@wdc.com> On Thu, Jan 18 2018 at 3:58P -0500, Bart Van Assche <Bart.VanAssche@wdc.com> 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
WARNING: multiple messages have this Message-ID (diff)
From: Mike Snitzer <snitzer@redhat.com> To: Bart Van Assche <Bart.VanAssche@wdc.com> Cc: "axboe@kernel.dk" <axboe@kernel.dk>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "ming.lei@redhat.com" <ming.lei@redhat.com>, "hch@infradead.org" <hch@infradead.org>, "dm-devel@redhat.com" <dm-devel@redhat.com>, "osandov@fb.com" <osandov@fb.com> Subject: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Date: Thu, 18 Jan 2018 16:23:27 -0500 [thread overview] Message-ID: <20180118212327.GB31679@redhat.com> (raw) In-Reply-To: <1516309128.2676.38.camel@wdc.com> On Thu, Jan 18 2018 at 3:58P -0500, Bart Van Assche <Bart.VanAssche@wdc.com> 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
next prev parent reply other threads:[~2018-01-18 21:23 UTC|newest] Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-01-18 2:41 [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Ming Lei 2018-01-18 16:50 ` Bart Van Assche 2018-01-18 17:03 ` Mike Snitzer 2018-01-18 17:03 ` Mike Snitzer 2018-01-18 17:20 ` Bart Van Assche 2018-01-18 17:20 ` Bart Van Assche 2018-01-18 18:30 ` Mike Snitzer 2018-01-18 18:47 ` Bart Van Assche 2018-01-18 18:47 ` Bart Van Assche 2018-01-18 20:11 ` Jens Axboe 2018-01-18 20:11 ` Jens Axboe 2018-01-18 20:48 ` Mike Snitzer 2018-01-18 20:58 ` Bart Van Assche 2018-01-18 20:58 ` Bart Van Assche 2018-01-18 21:23 ` Mike Snitzer [this message] 2018-01-18 21:23 ` Mike Snitzer 2018-01-18 21:37 ` Laurence Oberman 2018-01-18 21:39 ` [dm-devel] " Bart Van Assche 2018-01-18 21:39 ` Bart Van Assche 2018-01-18 21:45 ` Laurence Oberman 2018-01-18 21:45 ` Laurence Oberman 2018-01-18 22:01 ` Mike Snitzer 2018-01-18 22:18 ` Laurence Oberman 2018-01-18 22:20 ` Laurence Oberman 2018-01-18 22:20 ` Laurence Oberman 2018-01-18 22:24 ` Bart Van Assche 2018-01-18 22:24 ` Bart Van Assche 2018-01-18 22:35 ` Laurence Oberman 2018-01-18 22:39 ` Jens Axboe 2018-01-18 22:55 ` Bart Van Assche 2018-01-18 22:55 ` Bart Van Assche 2018-01-18 22:20 ` Bart Van Assche 2018-01-18 22:20 ` Bart Van Assche 2018-01-23 9:22 ` [PATCH] block: neutralize blk_insert_cloned_request IO stall regression (was: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle) Mike Snitzer 2018-01-23 10:53 ` Ming Lei 2018-01-23 12:15 ` Mike Snitzer 2018-01-23 12:17 ` Ming Lei 2018-01-23 12:43 ` Mike Snitzer 2018-01-23 16:43 ` [PATCH] " Bart Van Assche 2018-01-23 16:43 ` Bart Van Assche 2018-01-19 2:32 ` [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Ming Lei 2018-01-19 4:02 ` Jens Axboe 2018-01-19 7:26 ` Ming Lei 2018-01-19 15:20 ` Bart Van Assche 2018-01-19 15:20 ` Bart Van Assche 2018-01-19 15:25 ` Jens Axboe 2018-01-19 15:33 ` Ming Lei 2018-01-19 16:06 ` Bart Van Assche 2018-01-19 16:06 ` Bart Van Assche 2018-01-19 15:24 ` Jens Axboe 2018-01-19 15:40 ` Ming Lei 2018-01-19 15:40 ` Ming Lei 2018-01-19 15:48 ` Jens Axboe 2018-01-19 16:05 ` Ming Lei 2018-01-19 16:19 ` Jens Axboe 2018-01-19 16:26 ` Ming Lei 2018-01-19 16:27 ` Jens Axboe 2018-01-19 16:37 ` Ming Lei 2018-01-19 16:41 ` Jens Axboe 2018-01-19 16:41 ` Jens Axboe 2018-01-19 16:47 ` Mike Snitzer 2018-01-19 16:52 ` Jens Axboe 2018-01-19 17:05 ` Ming Lei 2018-01-19 17:09 ` Jens Axboe 2018-01-19 17:20 ` Ming Lei 2018-01-19 17:38 ` Jens Axboe 2018-01-19 18:24 ` Ming Lei 2018-01-19 18:24 ` Ming Lei 2018-01-19 18:33 ` Mike Snitzer 2018-01-19 23:52 ` Ming Lei 2018-01-20 4:27 ` Jens Axboe 2018-01-19 16:13 ` Mike Snitzer 2018-01-19 16:23 ` Jens Axboe 2018-01-19 23:57 ` Ming Lei 2018-01-29 22:37 ` Bart Van Assche 2018-01-19 5:09 ` Bart Van Assche 2018-01-19 5:09 ` Bart Van Assche 2018-01-19 7:34 ` Ming Lei 2018-01-19 19:47 ` Bart Van Assche 2018-01-19 19:47 ` Bart Van Assche
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