diff mbox series

[1/2] blk-mq: adjust debugfs and sysfs register when updating nr_hw_queues

Message ID 1538044984-2147-2-git-send-email-jianchao.w.wang@oracle.com (mailing list archive)
State New, archived
Headers show
Series blk-mq: two fixes about updating hw queues | expand

Commit Message

jianchao.wang Sept. 27, 2018, 10:43 a.m. UTC 
blk-mq debugfs and sysfs entries need to be removed before updating
queue map, otherwise, we get get wrong result there. This patch fixes
it and remove the redundant debugfs and sysfs register/unregister
operations during __blk_mq_update_nr_hw_queues.

Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
 block/blk-mq.c | 39 ++++++++++++---------------------------
 1 file changed, 12 insertions(+), 27 deletions(-)

Comments

Ming Lei Sept. 29, 2018, 2:49 a.m. UTC | #1 
On Thu, Sep 27, 2018 at 06:43:03PM +0800, Jianchao Wang wrote:
> blk-mq debugfs and sysfs entries need to be removed before updating
> queue map, otherwise, we get get wrong result there. This patch fixes
> it and remove the redundant debugfs and sysfs register/unregister
> operations during __blk_mq_update_nr_hw_queues.
> 
> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
> ---
>  block/blk-mq.c | 39 ++++++++++++---------------------------
>  1 file changed, 12 insertions(+), 27 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 85a1c1a..6356455 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2137,8 +2137,6 @@ static void blk_mq_exit_hctx(struct request_queue *q,
>  		struct blk_mq_tag_set *set,
>  		struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
>  {
> -	blk_mq_debugfs_unregister_hctx(hctx);
> -
>  	if (blk_mq_hw_queue_mapped(hctx))
>  		blk_mq_tag_idle(hctx);
>  
> @@ -2165,6 +2163,7 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
>  	queue_for_each_hw_ctx(q, hctx, i) {
>  		if (i == nr_queue)
>  			break;
> +		blk_mq_debugfs_unregister_hctx(hctx);
>  		blk_mq_exit_hctx(q, set, hctx, i);
>  	}
>  }
> @@ -2222,8 +2221,6 @@ static int blk_mq_init_hctx(struct request_queue *q,
>  	if (hctx->flags & BLK_MQ_F_BLOCKING)
>  		init_srcu_struct(hctx->srcu);
>  
> -	blk_mq_debugfs_register_hctx(q, hctx);
> -
>  	return 0;
>  
>   free_fq:
> @@ -2512,8 +2509,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
>  	int i, j;
>  	struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
>  
> -	blk_mq_sysfs_unregister(q);
> -
>  	/* protect against switching io scheduler  */
>  	mutex_lock(&q->sysfs_lock);
>  	for (i = 0; i < set->nr_hw_queues; i++) {
> @@ -2561,7 +2556,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
>  	}
>  	q->nr_hw_queues = i;
>  	mutex_unlock(&q->sysfs_lock);
> -	blk_mq_sysfs_register(q);
>  }
>  
>  struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
> @@ -2659,25 +2653,6 @@ void blk_mq_free_queue(struct request_queue *q)
>  	blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
>  }

Looks both blk_mq_sysfs_register() and blk_mq_debugfs_register_hctx()
are removed from the path of blk_mq_init_allocated_queue(), so where are
the two registered for a freshly new queue?

Thanks,
Ming
jianchao.wang Sept. 29, 2018, 3:02 a.m. UTC | #2 
Hi Ming

On 09/29/2018 10:49 AM, Ming Lei wrote:
> Looks both blk_mq_sysfs_register() and blk_mq_debugfs_register_hctx()
> are removed from the path of blk_mq_init_allocated_queue(), so where are
> the two registered for a freshly new queue?

Initially, both of them are registered by following path.
__device_add_disk
  -> blk_register_queue

	if (q->mq_ops) {
		__blk_mq_register_dev(dev, q);
		blk_mq_debugfs_register(q);
	}

blk_mq_init_allocated_queue won't do any thing.

Thanks
Jianchao
Ming Lei Oct. 9, 2018, 2:49 a.m. UTC | #3 
On Thu, Sep 27, 2018 at 06:43:03PM +0800, Jianchao Wang wrote:
> blk-mq debugfs and sysfs entries need to be removed before updating
> queue map, otherwise, we get get wrong result there. This patch fixes
> it and remove the redundant debugfs and sysfs register/unregister
> operations during __blk_mq_update_nr_hw_queues.
> 
> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
> ---
>  block/blk-mq.c | 39 ++++++++++++---------------------------
>  1 file changed, 12 insertions(+), 27 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 85a1c1a..6356455 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2137,8 +2137,6 @@ static void blk_mq_exit_hctx(struct request_queue *q,
>  		struct blk_mq_tag_set *set,
>  		struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
>  {
> -	blk_mq_debugfs_unregister_hctx(hctx);
> -
>  	if (blk_mq_hw_queue_mapped(hctx))
>  		blk_mq_tag_idle(hctx);
>  
> @@ -2165,6 +2163,7 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
>  	queue_for_each_hw_ctx(q, hctx, i) {
>  		if (i == nr_queue)
>  			break;
> +		blk_mq_debugfs_unregister_hctx(hctx);
>  		blk_mq_exit_hctx(q, set, hctx, i);
>  	}
>  }
> @@ -2222,8 +2221,6 @@ static int blk_mq_init_hctx(struct request_queue *q,
>  	if (hctx->flags & BLK_MQ_F_BLOCKING)
>  		init_srcu_struct(hctx->srcu);
>  
> -	blk_mq_debugfs_register_hctx(q, hctx);
> -
>  	return 0;
>  
>   free_fq:
> @@ -2512,8 +2509,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
>  	int i, j;
>  	struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
>  
> -	blk_mq_sysfs_unregister(q);
> -
>  	/* protect against switching io scheduler  */
>  	mutex_lock(&q->sysfs_lock);
>  	for (i = 0; i < set->nr_hw_queues; i++) {
> @@ -2561,7 +2556,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
>  	}
>  	q->nr_hw_queues = i;
>  	mutex_unlock(&q->sysfs_lock);
> -	blk_mq_sysfs_register(q);
>  }
>  
>  struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
> @@ -2659,25 +2653,6 @@ void blk_mq_free_queue(struct request_queue *q)
>  	blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
>  }
>  
> -/* Basically redo blk_mq_init_queue with queue frozen */
> -static void blk_mq_queue_reinit(struct request_queue *q)
> -{
> -	WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
> -
> -	blk_mq_debugfs_unregister_hctxs(q);
> -	blk_mq_sysfs_unregister(q);
> -
> -	/*
> -	 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
> -	 * we should change hctx numa_node according to the new topology (this
> -	 * involves freeing and re-allocating memory, worth doing?)
> -	 */
> -	blk_mq_map_swqueue(q);
> -
> -	blk_mq_sysfs_register(q);
> -	blk_mq_debugfs_register_hctxs(q);
> -}
> -
>  static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
>  {
>  	int i;
> @@ -2987,11 +2962,21 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
>  		if (!blk_mq_elv_switch_none(&head, q))
>  			goto switch_back;
>  
> +	list_for_each_entry(q, &set->tag_list, tag_set_list) {
> +		blk_mq_debugfs_unregister_hctxs(q);
> +		blk_mq_sysfs_unregister(q);
> +	}
> +
>  	set->nr_hw_queues = nr_hw_queues;
>  	blk_mq_update_queue_map(set);
>  	list_for_each_entry(q, &set->tag_list, tag_set_list) {
>  		blk_mq_realloc_hw_ctxs(set, q);
> -		blk_mq_queue_reinit(q);
> +		blk_mq_map_swqueue(q);
> +	}
> +
> +	list_for_each_entry(q, &set->tag_list, tag_set_list) {
> +		blk_mq_sysfs_register(q);
> +		blk_mq_debugfs_register_hctxs(q);
>  	}
>  
>  switch_back:
> -- 
> 2.7.4
> 

Reviewed-by: Ming Lei <ming.lei@redhat.com>

Thanks,
Ming
diff mbox series

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 85a1c1a..6356455 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2137,8 +2137,6 @@  static void blk_mq_exit_hctx(struct request_queue *q,
 		struct blk_mq_tag_set *set,
 		struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
 {
-	blk_mq_debugfs_unregister_hctx(hctx);
-
 	if (blk_mq_hw_queue_mapped(hctx))
 		blk_mq_tag_idle(hctx);
 
@@ -2165,6 +2163,7 @@  static void blk_mq_exit_hw_queues(struct request_queue *q,
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (i == nr_queue)
 			break;
+		blk_mq_debugfs_unregister_hctx(hctx);
 		blk_mq_exit_hctx(q, set, hctx, i);
 	}
 }
@@ -2222,8 +2221,6 @@  static int blk_mq_init_hctx(struct request_queue *q,
 	if (hctx->flags & BLK_MQ_F_BLOCKING)
 		init_srcu_struct(hctx->srcu);
 
-	blk_mq_debugfs_register_hctx(q, hctx);
-
 	return 0;
 
  free_fq:
@@ -2512,8 +2509,6 @@  static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
 	int i, j;
 	struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
 
-	blk_mq_sysfs_unregister(q);
-
 	/* protect against switching io scheduler  */
 	mutex_lock(&q->sysfs_lock);
 	for (i = 0; i < set->nr_hw_queues; i++) {
@@ -2561,7 +2556,6 @@  static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
 	}
 	q->nr_hw_queues = i;
 	mutex_unlock(&q->sysfs_lock);
-	blk_mq_sysfs_register(q);
 }
 
 struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
@@ -2659,25 +2653,6 @@  void blk_mq_free_queue(struct request_queue *q)
 	blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
 }
 
-/* Basically redo blk_mq_init_queue with queue frozen */
-static void blk_mq_queue_reinit(struct request_queue *q)
-{
-	WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
-
-	blk_mq_debugfs_unregister_hctxs(q);
-	blk_mq_sysfs_unregister(q);
-
-	/*
-	 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
-	 * we should change hctx numa_node according to the new topology (this
-	 * involves freeing and re-allocating memory, worth doing?)
-	 */
-	blk_mq_map_swqueue(q);
-
-	blk_mq_sysfs_register(q);
-	blk_mq_debugfs_register_hctxs(q);
-}
-
 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
 {
 	int i;
@@ -2987,11 +2962,21 @@  static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
 		if (!blk_mq_elv_switch_none(&head, q))
 			goto switch_back;
 
+	list_for_each_entry(q, &set->tag_list, tag_set_list) {
+		blk_mq_debugfs_unregister_hctxs(q);
+		blk_mq_sysfs_unregister(q);
+	}
+
 	set->nr_hw_queues = nr_hw_queues;
 	blk_mq_update_queue_map(set);
 	list_for_each_entry(q, &set->tag_list, tag_set_list) {
 		blk_mq_realloc_hw_ctxs(set, q);
-		blk_mq_queue_reinit(q);
+		blk_mq_map_swqueue(q);
+	}
+
+	list_for_each_entry(q, &set->tag_list, tag_set_list) {
+		blk_mq_sysfs_register(q);
+		blk_mq_debugfs_register_hctxs(q);
 	}
 
 switch_back: