* [PATCH 0/3] Avoid that scsi-mq queue processing stalls
@ 2017-03-31 23:12 Bart Van Assche
2017-03-31 23:12 ` [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues Bart Van Assche
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Bart Van Assche @ 2017-03-31 23:12 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley, Bart Van Assche
Hello Jens,
The three patches in this patch series fix the queue lockup I reported
a few days ago on the linux-block mailing list. Please consider these
patches for kernel v4.11.
Thanks,
Bart.
Bart Van Assche (3):
blk-mq: Introduce blk_mq_ops.restart_queues
scsi: Add scsi_restart_queues()
scsi: Ensure that scsi_run_queue() runs all hardware queues
block/blk-mq-sched.c | 11 +++--------
block/blk-mq-sched.h | 14 --------------
drivers/scsi/scsi_lib.c | 20 +++++++++++++++++---
include/linux/blk-mq.h | 4 ++++
include/linux/blkdev.h | 1 -
5 files changed, 24 insertions(+), 26 deletions(-)
--
2.12.0
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues
2017-03-31 23:12 [PATCH 0/3] Avoid that scsi-mq queue processing stalls Bart Van Assche
@ 2017-03-31 23:12 ` Bart Van Assche
2017-04-03 6:10 ` Hannes Reinecke
2017-03-31 23:12 ` [PATCH 2/3] scsi: Add scsi_restart_queues() Bart Van Assche
2017-03-31 23:12 ` [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues Bart Van Assche
2 siblings, 1 reply; 8+ messages in thread
From: Bart Van Assche @ 2017-03-31 23:12 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Bart Van Assche, Christoph Hellwig, Hannes Reinecke
If a tag set is shared among multiple request queues, leave
it to the block driver to restart queues. Hence remove
QUEUE_FLAG_RESTART and introduce blk_mq_ops.restart_queues.
Remove blk_mq_sched_mark_restart_queue() because this
function has no callers.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
---
block/blk-mq-sched.c | 11 +++--------
block/blk-mq-sched.h | 14 --------------
include/linux/blk-mq.h | 4 ++++
include/linux/blkdev.h | 1 -
4 files changed, 7 insertions(+), 23 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 09af8ff18719..ed9942ee0146 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -329,16 +329,11 @@ static void blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx)
void blk_mq_sched_restart_queues(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
- unsigned int i;
- if (test_bit(QUEUE_FLAG_RESTART, &q->queue_flags)) {
- if (test_and_clear_bit(QUEUE_FLAG_RESTART, &q->queue_flags)) {
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_sched_restart_hctx(hctx);
- }
- } else {
+ if (q->mq_ops->restart_queues)
+ q->mq_ops->restart_queues(q);
+ else
blk_mq_sched_restart_hctx(hctx);
- }
}
/*
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index a75b16b123f7..fe62b1eccf4c 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -131,20 +131,6 @@ static inline void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx)
set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
}
-/*
- * Mark a hardware queue and the request queue it belongs to as needing a
- * restart.
- */
-static inline void blk_mq_sched_mark_restart_queue(struct blk_mq_hw_ctx *hctx)
-{
- struct request_queue *q = hctx->queue;
-
- if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
- set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
- if (!test_bit(QUEUE_FLAG_RESTART, &q->queue_flags))
- set_bit(QUEUE_FLAG_RESTART, &q->queue_flags);
-}
-
static inline bool blk_mq_sched_needs_restart(struct blk_mq_hw_ctx *hctx)
{
return test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index ea2e9dcd3aef..75160e9470cb 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -86,6 +86,7 @@ struct blk_mq_queue_data {
};
typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *);
+typedef void (restart_fn)(struct request_queue *q);
typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
@@ -108,6 +109,9 @@ struct blk_mq_ops {
*/
queue_rq_fn *queue_rq;
+ /* Called upon request completion to rerun all queues */
+ restart_fn *restart_queues;
+
/*
* Called on request timeout
*/
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a2dc6b390d48..a80543ec8be7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -615,7 +615,6 @@ struct request_queue {
#define QUEUE_FLAG_FLUSH_NQ 25 /* flush not queueuable */
#define QUEUE_FLAG_DAX 26 /* device supports DAX */
#define QUEUE_FLAG_STATS 27 /* track rq completion times */
-#define QUEUE_FLAG_RESTART 28 /* queue needs restart at completion */
#define QUEUE_FLAG_POLL_STATS 29 /* collecting stats for hybrid polling */
#define QUEUE_FLAG_REGISTERED 30 /* queue has been registered to a disk */
--
2.12.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/3] scsi: Add scsi_restart_queues()
2017-03-31 23:12 [PATCH 0/3] Avoid that scsi-mq queue processing stalls Bart Van Assche
2017-03-31 23:12 ` [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues Bart Van Assche
@ 2017-03-31 23:12 ` Bart Van Assche
2017-04-03 6:10 ` Hannes Reinecke
2017-03-31 23:12 ` [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues Bart Van Assche
2 siblings, 1 reply; 8+ messages in thread
From: Bart Van Assche @ 2017-03-31 23:12 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Bart Van Assche, Christoph Hellwig, Hannes Reinecke
This patch avoids that if multiple SCSI devices are associated with
a SCSI host that a queue can get stuck if scsi_queue_rq() returns
"busy".
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/scsi_lib.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c1519660824b..1d804e33971a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -555,6 +555,21 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
scsi_run_queue(sdev->request_queue);
}
+static void scsi_restart_queues(struct request_queue *q)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ __shost_for_each_device(sdev, shost) {
+ q = sdev->request_queue;
+ if (q->mq_ops && !blk_queue_dying(q))
+ blk_mq_run_hw_queues(q, true);
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+}
+
static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
{
if (!blk_rq_is_passthrough(cmd->request)) {
@@ -2156,6 +2171,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
static const struct blk_mq_ops scsi_mq_ops = {
.queue_rq = scsi_queue_rq,
+ .restart_queues = scsi_restart_queues,
.complete = scsi_softirq_done,
.timeout = scsi_timeout,
.init_request = scsi_init_request,
--
2.12.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues
2017-03-31 23:12 [PATCH 0/3] Avoid that scsi-mq queue processing stalls Bart Van Assche
2017-03-31 23:12 ` [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues Bart Van Assche
2017-03-31 23:12 ` [PATCH 2/3] scsi: Add scsi_restart_queues() Bart Van Assche
@ 2017-03-31 23:12 ` Bart Van Assche
2017-04-02 7:49 ` Sagi Grimberg
2017-04-03 6:12 ` Hannes Reinecke
2 siblings, 2 replies; 8+ messages in thread
From: Bart Van Assche @ 2017-03-31 23:12 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Bart Van Assche, Christoph Hellwig, Hannes Reinecke,
Sagi Grimberg
commit 52d7f1b5c2f3 ("blk-mq: Avoid that requeueing starts stopped
queues") removed the blk_mq_stop_hw_queue() call from scsi_queue_rq()
for the BLK_MQ_RQ_QUEUE_BUSY case. blk_mq_start_stopped_hw_queues()
only runs queues that had been stopped. Hence change the
blk_mq_start_stopped_hw_queues() call in scsi_run_queue() into
blk_mq_run_hw_queues(). Remove the blk_mq_start_stopped_hw_queues()
call from scsi_end_request() because __blk_mq_finish_request()
already runs all hardware queues if needed.
Fixes: commit 52d7f1b5c2f3 ("blk-mq: Avoid that requeueing starts stopped queues")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
---
drivers/scsi/scsi_lib.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1d804e33971a..3323878423ac 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -496,7 +496,7 @@ static void scsi_run_queue(struct request_queue *q)
scsi_starved_list_run(sdev->host);
if (q->mq_ops)
- blk_mq_start_stopped_hw_queues(q, false);
+ blk_mq_run_hw_queues(q, false);
else
blk_run_queue(q);
}
@@ -681,8 +681,6 @@ static bool scsi_end_request(struct request *req, int error,
if (scsi_target(sdev)->single_lun ||
!list_empty(&sdev->host->starved_list))
kblockd_schedule_work(&sdev->requeue_work);
- else
- blk_mq_start_stopped_hw_queues(q, true);
} else {
unsigned long flags;
--
2.12.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues
2017-03-31 23:12 ` [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues Bart Van Assche
@ 2017-04-02 7:49 ` Sagi Grimberg
2017-04-03 6:12 ` Hannes Reinecke
1 sibling, 0 replies; 8+ messages in thread
From: Sagi Grimberg @ 2017-04-02 7:49 UTC (permalink / raw)
To: Bart Van Assche, Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Christoph Hellwig, Hannes Reinecke
Looks good,
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues
2017-03-31 23:12 ` [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues Bart Van Assche
@ 2017-04-03 6:10 ` Hannes Reinecke
0 siblings, 0 replies; 8+ messages in thread
From: Hannes Reinecke @ 2017-04-03 6:10 UTC (permalink / raw)
To: Bart Van Assche, Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Christoph Hellwig, Hannes Reinecke
On 04/01/2017 01:12 AM, Bart Van Assche wrote:
> If a tag set is shared among multiple request queues, leave
> it to the block driver to restart queues. Hence remove
> QUEUE_FLAG_RESTART and introduce blk_mq_ops.restart_queues.
> Remove blk_mq_sched_mark_restart_queue() because this
> function has no callers.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> ---
> block/blk-mq-sched.c | 11 +++--------
> block/blk-mq-sched.h | 14 --------------
> include/linux/blk-mq.h | 4 ++++
> include/linux/blkdev.h | 1 -
> 4 files changed, 7 insertions(+), 23 deletions(-)
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
GF: F. Imend�rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG N�rnberg)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/3] scsi: Add scsi_restart_queues()
2017-03-31 23:12 ` [PATCH 2/3] scsi: Add scsi_restart_queues() Bart Van Assche
@ 2017-04-03 6:10 ` Hannes Reinecke
0 siblings, 0 replies; 8+ messages in thread
From: Hannes Reinecke @ 2017-04-03 6:10 UTC (permalink / raw)
To: Bart Van Assche, Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Christoph Hellwig, Hannes Reinecke
On 04/01/2017 01:12 AM, Bart Van Assche wrote:
> This patch avoids that if multiple SCSI devices are associated with
> a SCSI host that a queue can get stuck if scsi_queue_rq() returns
> "busy".
>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.com>
> ---
> drivers/scsi/scsi_lib.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
GF: F. Imend�rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG N�rnberg)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues
2017-03-31 23:12 ` [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues Bart Van Assche
2017-04-02 7:49 ` Sagi Grimberg
@ 2017-04-03 6:12 ` Hannes Reinecke
1 sibling, 0 replies; 8+ messages in thread
From: Hannes Reinecke @ 2017-04-03 6:12 UTC (permalink / raw)
To: Bart Van Assche, Jens Axboe
Cc: linux-block, Martin K . Petersen, James Bottomley,
Christoph Hellwig, Sagi Grimberg
On 04/01/2017 01:12 AM, Bart Van Assche wrote:
> commit 52d7f1b5c2f3 ("blk-mq: Avoid that requeueing starts stopped
> queues") removed the blk_mq_stop_hw_queue() call from scsi_queue_rq()
> for the BLK_MQ_RQ_QUEUE_BUSY case. blk_mq_start_stopped_hw_queues()
> only runs queues that had been stopped. Hence change the
> blk_mq_start_stopped_hw_queues() call in scsi_run_queue() into
> blk_mq_run_hw_queues(). Remove the blk_mq_start_stopped_hw_queues()
> call from scsi_end_request() because __blk_mq_finish_request()
> already runs all hardware queues if needed.
>
> Fixes: commit 52d7f1b5c2f3 ("blk-mq: Avoid that requeueing starts stopped queues")
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> ---
> drivers/scsi/scsi_lib.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
GF: F. Imend�rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG N�rnberg)
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-04-03 6:12 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2017-03-31 23:12 [PATCH 0/3] Avoid that scsi-mq queue processing stalls Bart Van Assche
2017-03-31 23:12 ` [PATCH 1/3] blk-mq: Introduce blk_mq_ops.restart_queues Bart Van Assche
2017-04-03 6:10 ` Hannes Reinecke
2017-03-31 23:12 ` [PATCH 2/3] scsi: Add scsi_restart_queues() Bart Van Assche
2017-04-03 6:10 ` Hannes Reinecke
2017-03-31 23:12 ` [PATCH 3/3] scsi: Ensure that scsi_run_queue() runs all hardware queues Bart Van Assche
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