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From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
	John Garry <john.garry@huawei.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Keith Busch <keith.busch@intel.com>
Subject: [PATCH V4 5/5] blk-mq: handle requests dispatched from IO scheduler in case that hctx is dead
Date: Mon, 14 Oct 2019 09:50:43 +0800	[thread overview]
Message-ID: <20191014015043.25029-6-ming.lei@redhat.com> (raw)
In-Reply-To: <20191014015043.25029-1-ming.lei@redhat.com>

If hctx becomes dead, all in-queue IO requests aimed at this hctx have to
be re-submitted, so cover requests queued in scheduler queue.

Cc: John Garry <john.garry@huawei.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Keith Busch <keith.busch@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 17f0a9ef32a8..06081966549f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2305,6 +2305,7 @@ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
 	enum hctx_type type;
 	bool hctx_dead;
 	struct request *rq;
+	struct elevator_queue *e;
 
 	hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
 	ctx = __blk_mq_get_ctx(hctx->queue, cpu);
@@ -2315,12 +2316,31 @@ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
 	hctx_dead = cpumask_first_and(hctx->cpumask, cpu_online_mask) >=
 		nr_cpu_ids;
 
-	spin_lock(&ctx->lock);
-	if (!list_empty(&ctx->rq_lists[type])) {
-		list_splice_init(&ctx->rq_lists[type], &tmp);
-		blk_mq_hctx_clear_pending(hctx, ctx);
+	e = hctx->queue->elevator;
+	if (!e) {
+		spin_lock(&ctx->lock);
+		if (!list_empty(&ctx->rq_lists[type])) {
+			list_splice_init(&ctx->rq_lists[type], &tmp);
+			blk_mq_hctx_clear_pending(hctx, ctx);
+		}
+		spin_unlock(&ctx->lock);
+	} else if (hctx_dead) {
+		LIST_HEAD(sched_tmp);
+
+		while ((rq = e->type->ops.dispatch_request(hctx))) {
+			if (rq->mq_hctx != hctx)
+				list_add(&rq->queuelist, &sched_tmp);
+			else
+				list_add(&rq->queuelist, &tmp);
+		}
+
+		while (!list_empty(&sched_tmp)) {
+			rq = list_entry(sched_tmp.next, struct request,
+					queuelist);
+			list_del_init(&rq->queuelist);
+			blk_mq_sched_insert_request(rq, true, true, true);
+		}
 	}
-	spin_unlock(&ctx->lock);
 
 	if (!hctx_dead) {
 		if (list_empty(&tmp))
-- 
2.20.1


  parent reply	other threads:[~2019-10-14  1:51 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-14  1:50 [PATCH V4 0/5] blk-mq: improvement on handling IO during CPU hotplug Ming Lei
2019-10-14  1:50 ` [PATCH V4 1/5] blk-mq: add new state of BLK_MQ_S_INTERNAL_STOPPED Ming Lei
2019-10-14  1:50 ` [PATCH V4 2/5] blk-mq: prepare for draining IO when hctx's all CPUs are offline Ming Lei
2019-10-14  1:50 ` [PATCH V4 3/5] blk-mq: stop to handle IO and drain IO before hctx becomes dead Ming Lei
2019-11-28  9:29   ` John Garry
2019-10-14  1:50 ` [PATCH V4 4/5] blk-mq: re-submit IO in case that hctx is dead Ming Lei
2019-10-14  1:50 ` Ming Lei [this message]
2019-10-16  8:58 ` [PATCH V4 0/5] blk-mq: improvement on handling IO during CPU hotplug John Garry
2019-10-16 12:07   ` Ming Lei
2019-10-16 16:19     ` John Garry
     [not found]       ` <55a84ea3-647d-0a76-596c-c6c6b2fc1b75@huawei.com>
2019-10-20 10:14         ` Ming Lei
2019-10-21  9:19           ` John Garry
2019-10-21  9:34             ` Ming Lei
2019-10-21  9:47               ` John Garry
2019-10-21 10:24                 ` Ming Lei
2019-10-21 11:49                   ` John Garry
2019-10-21 12:53                     ` Ming Lei
2019-10-21 14:02                       ` John Garry
2019-10-22  0:16                         ` Ming Lei
2019-10-22 11:19                           ` John Garry
2019-10-22 13:45                             ` Ming Lei
2019-10-25 16:33             ` John Garry
2019-10-28 10:42               ` Ming Lei
2019-10-28 11:55                 ` John Garry
2019-10-29  1:50                   ` Ming Lei
2019-10-29  9:22                     ` John Garry
2019-10-29 10:05                       ` Ming Lei
2019-10-29 17:54                         ` John Garry
2019-10-31 16:28                         ` John Garry
2019-11-28  1:09 ` chenxiang (M)
2019-11-28  2:02   ` Ming Lei
2019-11-28 10:45     ` John Garry

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