[PATCH 13/14] blk-mq: add tagset quiesce interface

Christoph Hellwig
2022-11-01T15:02:17Z

From: Chao Leng <lengchao@huawei.com>

Drivers that have shared tagsets may need to quiesce potentially a lot
of request queues that all share a single tagset (e.g. nvme). Add an
interface to quiesce all the queues on a given tagset. This interface is
useful because it can speedup the quiesce by doing it in parallel.

Because some queues should not need to be quiesced (e.g. the nvme
connect_q) when quiescing the tagset, introduce a
QUEUE_FLAG_SKIP_TAGSET_QUIESCE flag to allow this new interface to
ski quiescing a particular queue.

Signed-off-by: Chao Leng <lengchao@huawei.com>
[hch: simplify for the per-tag_set srcu_struct]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
block/blk-mq.c | 27 +++++++++++++++++++++++++++
include/linux/blk-mq.h | 2 ++
include/linux/blkdev.h | 3 +++
3 files changed, 32 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index b358328a1dce3..f0dd07bbf4c16 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -315,6 +315,33 @@ void blk_mq_unquiesce_queue(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);

+void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
+{
+ struct request_queue *q;
+
+ mutex_lock(&set->tag_list_lock);
+ list_for_each_entry(q, &set->tag_list, tag_set_list) {
+ if (!blk_queue_skip_tagset_quiesce(q))
+ blk_mq_quiesce_queue_nowait(q);
+ }
+ blk_mq_wait_quiesce_done(set);
+ mutex_unlock(&set->tag_list_lock);
+}
+EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
+
+void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
+{
+ struct request_queue *q;
+
+ mutex_lock(&set->tag_list_lock);
+ list_for_each_entry(q, &set->tag_list, tag_set_list) {
+ if (!blk_queue_skip_tagset_quiesce(q))
+ blk_mq_unquiesce_queue(q);
+ }
+ mutex_unlock(&set->tag_list_lock);
+}
+EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
+
void blk_mq_wake_waiters(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 061ea6e7af017..109a0e30c4704 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -881,6 +881,8 @@ void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
void blk_mq_quiesce_queue(struct request_queue *q);
void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set);
+void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set);
+void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set);
void blk_mq_unquiesce_queue(struct request_queue *q);
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6a6fa167fc828..9188aa3f62595 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -571,6 +571,7 @@ struct request_queue {
#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
#define QUEUE_FLAG_NOWAIT 29 /* device supports NOWAIT */
#define QUEUE_FLAG_SQ_SCHED 30 /* single queue style io dispatch */
+#define QUEUE_FLAG_SKIP_TAGSET_QUIESCE 31 /* quiesce_tagset skip the queue*/

#define QUEUE_FLAG_MQ_DEFAULT ((1UL << QUEUE_FLAG_IO_STAT) | \
(1UL << QUEUE_FLAG_SAME_COMP) | \
@@ -610,6 +611,8 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
#define blk_queue_pm_only(q) atomic_read(&(q)->pm_only)
#define blk_queue_registered(q) test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
#define blk_queue_sq_sched(q) test_bit(QUEUE_FLAG_SQ_SCHED, &(q)->queue_flags)
+#define blk_queue_skip_tagset_quiesce(q) \
+ test_bit(QUEUE_FLAG_SKIP_TAGSET_QUIESCE, &(q)->queue_flags)

extern void blk_set_pm_only(struct request_queue *q);
extern void blk_clear_pm_only(struct request_queue *q);
--
2.30.2