From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Chaitanya Kulkarni <chaitanyak@nvidia.com> Cc: Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>, Bart Van Assche <bvanassche@acm.org>, Ming Lei <ming.lei@redhat.com> Subject: [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Date: Sat, 9 Oct 2021 11:47:13 +0800 [thread overview] Message-ID: <20211009034713.1489183-7-ming.lei@redhat.com> (raw) In-Reply-To: <20211009034713.1489183-1-ming.lei@redhat.com> blk_mq_quiesce_queue() has been used a bit wide now, so far we don't support concurrent/nested quiesce. One biggest issue is that unquiesce can happen unexpectedly in case that quiesce/unquiesce are run concurrently from more than one context. This patch introduces q->mq_quiesce_depth to deal concurrent quiesce, and we only unquiesce queue when it is the last/outer-most one of all contexts. Several kernel panic issue has been reported[1][2][3] when running stress quiesce test. And this patch has been verified in these reports. [1] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m1fc52431fad7f33b1ffc3f12c4450e4238540787 [2] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m10ad90afeb9c8cc318334190a7c24c8b5c5e0722 [3] https://listman.redhat.com/archives/dm-devel/2021-September/msg00189.html Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq.c | 21 ++++++++++++++++++--- include/linux/blkdev.h | 2 ++ 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 21bf4c3f0825..cb58f21c5be9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -209,7 +209,12 @@ EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); */ void blk_mq_quiesce_queue_nowait(struct request_queue *q) { - blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); + unsigned long flags; + + spin_lock_irqsave(&q->queue_lock, flags); + if (!q->quiesce_depth++) + blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); + spin_unlock_irqrestore(&q->queue_lock, flags); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); @@ -250,10 +255,20 @@ EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); */ void blk_mq_unquiesce_queue(struct request_queue *q) { - blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); + unsigned long flags; + bool run_queue = false; + + spin_lock_irqsave(&q->queue_lock, flags); + WARN_ON_ONCE(q->quiesce_depth <= 0); + if (q->quiesce_depth > 0 && !--q->quiesce_depth) { + blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); + run_queue = true; + } + spin_unlock_irqrestore(&q->queue_lock, flags); /* dispatch requests which are inserted during quiescing */ - blk_mq_run_hw_queues(q, true); + if (run_queue) + blk_mq_run_hw_queues(q, true); } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0e960d74615e..74c60e2d61f9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -315,6 +315,8 @@ struct request_queue { */ struct mutex mq_freeze_lock; + int quiesce_depth; + struct blk_mq_tag_set *tag_set; struct list_head tag_set_list; struct bio_set bio_split; -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Chaitanya Kulkarni <chaitanyak@nvidia.com> Cc: Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>, Bart Van Assche <bvanassche@acm.org>, Ming Lei <ming.lei@redhat.com> Subject: [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Date: Sat, 9 Oct 2021 11:47:13 +0800 [thread overview] Message-ID: <20211009034713.1489183-7-ming.lei@redhat.com> (raw) In-Reply-To: <20211009034713.1489183-1-ming.lei@redhat.com> blk_mq_quiesce_queue() has been used a bit wide now, so far we don't support concurrent/nested quiesce. One biggest issue is that unquiesce can happen unexpectedly in case that quiesce/unquiesce are run concurrently from more than one context. This patch introduces q->mq_quiesce_depth to deal concurrent quiesce, and we only unquiesce queue when it is the last/outer-most one of all contexts. Several kernel panic issue has been reported[1][2][3] when running stress quiesce test. And this patch has been verified in these reports. [1] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m1fc52431fad7f33b1ffc3f12c4450e4238540787 [2] https://lore.kernel.org/linux-block/9b21c797-e505-3821-4f5b-df7bf9380328@huawei.com/T/#m10ad90afeb9c8cc318334190a7c24c8b5c5e0722 [3] https://listman.redhat.com/archives/dm-devel/2021-September/msg00189.html Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq.c | 21 ++++++++++++++++++--- include/linux/blkdev.h | 2 ++ 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 21bf4c3f0825..cb58f21c5be9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -209,7 +209,12 @@ EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); */ void blk_mq_quiesce_queue_nowait(struct request_queue *q) { - blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); + unsigned long flags; + + spin_lock_irqsave(&q->queue_lock, flags); + if (!q->quiesce_depth++) + blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); + spin_unlock_irqrestore(&q->queue_lock, flags); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); @@ -250,10 +255,20 @@ EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); */ void blk_mq_unquiesce_queue(struct request_queue *q) { - blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); + unsigned long flags; + bool run_queue = false; + + spin_lock_irqsave(&q->queue_lock, flags); + WARN_ON_ONCE(q->quiesce_depth <= 0); + if (q->quiesce_depth > 0 && !--q->quiesce_depth) { + blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); + run_queue = true; + } + spin_unlock_irqrestore(&q->queue_lock, flags); /* dispatch requests which are inserted during quiescing */ - blk_mq_run_hw_queues(q, true); + if (run_queue) + blk_mq_run_hw_queues(q, true); } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0e960d74615e..74c60e2d61f9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -315,6 +315,8 @@ struct request_queue { */ struct mutex mq_freeze_lock; + int quiesce_depth; + struct blk_mq_tag_set *tag_set; struct list_head tag_set_list; struct bio_set bio_split; -- 2.31.1 _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2021-10-09 3:48 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-09 3:47 [PATCH V3 0/6] blk-mq: support concurrent queue quiescing Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-09 3:47 ` [PATCH V3 1/6] nvme: add APIs for stopping/starting admin queue Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-09 3:47 ` [PATCH V3 2/6] nvme: apply nvme API to quiesce/unquiesce " Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-09 3:47 ` [PATCH V3 3/6] nvme: prepare for pairing quiescing and unquiescing Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-09 3:47 ` [PATCH V3 4/6] nvme: paring quiesce/unquiesce Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-12 10:36 ` Christoph Hellwig 2021-10-12 10:36 ` Christoph Hellwig 2021-10-12 15:01 ` Ming Lei 2021-10-12 15:01 ` Ming Lei 2021-10-12 15:07 ` Christoph Hellwig 2021-10-12 15:07 ` Christoph Hellwig 2021-10-12 15:17 ` Ming Lei 2021-10-12 15:17 ` Ming Lei 2021-10-13 12:23 ` Sagi Grimberg 2021-10-13 12:23 ` Sagi Grimberg 2021-10-09 3:47 ` [PATCH V3 5/6] nvme: loop: clear NVME_CTRL_ADMIN_Q_STOPPED after admin queue is reallocated Ming Lei 2021-10-09 3:47 ` Ming Lei 2021-10-09 3:47 ` Ming Lei [this message] 2021-10-09 3:47 ` [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Ming Lei 2021-10-12 10:30 ` Christoph Hellwig 2021-10-12 10:30 ` Christoph Hellwig 2021-10-12 15:06 ` Ming Lei 2021-10-12 15:06 ` Ming Lei 2021-10-12 15:08 ` Christoph Hellwig 2021-10-12 15:08 ` Christoph Hellwig 2021-10-12 15:13 ` Ming Lei 2021-10-12 15:13 ` Ming Lei
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