From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Minwoo Im <minwoo.im.dev@gmail.com>,
Ming Lei <ming.lei@redhat.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 V2 2/5] blk-mq: add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ
Date: Mon, 12 Aug 2019 21:43:09 +0800 [thread overview]
Message-ID: <20190812134312.16732-3-ming.lei@redhat.com> (raw)
In-Reply-To: <20190812134312.16732-1-ming.lei@redhat.com>
We will stop hw queue and wait for completion of in-flight requests
when one hctx is becoming dead in the following patch. This way may
cause dead-lock for some stacking blk-mq drivers, such as dm-rq and
loop.
Add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ and mark it for dm-rq and
loop, so we needn't to wait for completion of in-flight requests of
dm-rq & loop, then the potential dead-lock can be avoided.
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>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-mq-debugfs.c | 1 +
drivers/block/loop.c | 2 +-
drivers/md/dm-rq.c | 2 +-
include/linux/blk-mq.h | 1 +
4 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index af40a02c46ee..24fff8c90942 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -240,6 +240,7 @@ static const char *const hctx_flag_name[] = {
HCTX_FLAG_NAME(TAG_SHARED),
HCTX_FLAG_NAME(BLOCKING),
HCTX_FLAG_NAME(NO_SCHED),
+ HCTX_FLAG_NAME(NO_MANAGED_IRQ),
};
#undef HCTX_FLAG_NAME
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a7461f482467..50328b572853 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1989,7 +1989,7 @@ static int loop_add(struct loop_device **l, int i)
lo->tag_set.queue_depth = 128;
lo->tag_set.numa_node = NUMA_NO_NODE;
lo->tag_set.cmd_size = sizeof(struct loop_cmd);
- lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+ lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_NO_MANAGED_IRQ;
lo->tag_set.driver_data = lo;
err = blk_mq_alloc_tag_set(&lo->tag_set);
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 21d5c1784d0c..684f92988d40 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -547,7 +547,7 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
md->tag_set->ops = &dm_mq_ops;
md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
md->tag_set->numa_node = md->numa_node_id;
- md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
+ md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_NO_MANAGED_IRQ;
md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
md->tag_set->driver_data = md;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 5b2d263e0646..838a22888413 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -226,6 +226,7 @@ struct blk_mq_ops {
enum {
BLK_MQ_F_SHOULD_MERGE = 1 << 0,
BLK_MQ_F_TAG_SHARED = 1 << 1,
+ BLK_MQ_F_NO_MANAGED_IRQ = 1 << 2,
BLK_MQ_F_BLOCKING = 1 << 5,
BLK_MQ_F_NO_SCHED = 1 << 6,
BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
--
2.20.1
next prev parent reply other threads:[~2019-08-12 13:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 13:43 [PATCH V2 0/5] blk-mq: improvement on handling IO during CPU hotplug Ming Lei
2019-08-12 13:43 ` [PATCH V2 1/5] blk-mq: add new state of BLK_MQ_S_INTERNAL_STOPPED Ming Lei
2019-08-12 13:43 ` Ming Lei [this message]
2019-08-12 13:43 ` [PATCH V2 3/5] blk-mq: stop to handle IO before hctx's all CPUs become offline Ming Lei
2019-08-12 14:24 ` Hannes Reinecke
2019-08-12 22:24 ` Ming Lei
2019-08-12 13:43 ` [PATCH V2 4/5] blk-mq: re-submit IO in case that hctx is dead Ming Lei
2019-08-12 14:26 ` Hannes Reinecke
2019-08-12 22:30 ` Ming Lei
2019-08-12 13:43 ` [PATCH V2 5/5] blk-mq: handle requests dispatched from IO scheduler " Ming Lei
2019-08-12 13:46 ` [PATCH V2 0/5] blk-mq: improvement on handling IO during CPU hotplug Ming Lei
2019-08-12 16:21 ` John Garry
2019-08-12 22:45 ` Ming Lei
2019-08-22 17:39 ` John Garry
2019-10-02 9:56 ` John Garry
2019-10-02 14:36 ` Jens Axboe
2019-10-06 2:47 ` Ming Lei
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