Unverified Commit 5b6a8b03 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!3720 blk-mq: make fair tag sharing configurable 

Merge Pull Request from: @ci-robot 
 
PR sync from: Yu Kuai <yukuai3@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/WCDPGUN72BZSQPWC5LW2UNMUKBZPPZ5O/ 
Changes in v3:
 - add lockdep_assert_held() in queue_update_fair_tag_sharing()
 - use tag_set->flags instead of new field;

Changes in v2:
 - use a local variable for 'q->tag_set->disable_fair_tag_sharing' before
 iteration in queue_update_fair_tag_sharing();
 - only update fair tag sharing if blk_mq_realloc_tag_set_tags() succeed
 in __blk_mq_update_nr_hw_queues();

Yu Kuai (3):
  blk-mq: add apis to disable fair tag sharing
  scsi: core: make fair tag sharing configurable via sysfs
  scsi_lib: disable fair tag sharing by default if total tags is less
    than 128


-- 
2.39.2
 
https://gitee.com/openeuler/kernel/issues/I8RGGC 
 
Link:https://gitee.com/openeuler/kernel/pulls/3720

 

Reviewed-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parents 983e04be 02872718

block/blk-mq-debugfs.c

+1 −0
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ static const char *const hctx_flag_name[] = { 
	HCTX_FLAG_NAME(NO_SCHED),

	HCTX_FLAG_NAME(STACKING),

	HCTX_FLAG_NAME(TAG_HCTX_SHARED),

	HCTX_FLAG_NAME(DISABLE_FAIR_TAG_SHARING),

};

#undef HCTX_FLAG_NAME

block/blk-mq.c

+37 −1
Original line number Diff line number Diff line
@@ -3706,7 +3706,8 @@ blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, 
	spin_lock_init(&hctx->lock);

	INIT_LIST_HEAD(&hctx->dispatch);

	hctx->queue = q;

	hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;

	hctx->flags = set->flags & ~(BLK_MQ_F_TAG_QUEUE_SHARED |

				     BLK_MQ_F_DISABLE_FAIR_TAG_SHARING);



	INIT_LIST_HEAD(&hctx->hctx_list);
@@ -3935,6 +3936,37 @@ static void blk_mq_map_swqueue(struct request_queue *q) 
	}

}



static void queue_update_fair_tag_sharing(struct request_queue *q)

{

	struct blk_mq_hw_ctx *hctx;

	unsigned long i;

	bool disabled = q->tag_set->flags & BLK_MQ_F_DISABLE_FAIR_TAG_SHARING;



	lockdep_assert_held(&q->tag_set->tag_list_lock);



	queue_for_each_hw_ctx(q, hctx, i) {

		if (disabled)

			hctx->flags |= BLK_MQ_F_DISABLE_FAIR_TAG_SHARING;

		else

			hctx->flags &= ~BLK_MQ_F_DISABLE_FAIR_TAG_SHARING;

	}



}



void blk_mq_update_fair_tag_sharing(struct blk_mq_tag_set *set)

{

	struct request_queue *q;



	lockdep_assert_held(&set->tag_list_lock);



	list_for_each_entry(q, &set->tag_list, tag_set_list) {

		blk_mq_freeze_queue(q);

		queue_update_fair_tag_sharing(q);

		blk_mq_unfreeze_queue(q);

	}

}

EXPORT_SYMBOL_GPL(blk_mq_update_fair_tag_sharing);



/*

 * Caller needs to ensure that we're either frozen/quiesced, or that

 * the queue isn't live yet.
@@ -3989,6 +4021,7 @@ static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, 
{

	mutex_lock(&set->tag_list_lock);



	queue_update_fair_tag_sharing(q);

	/*

	 * Check to see if we're transitioning to shared (from 1 to 2 queues).

	 */
@@ -4767,6 +4800,9 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, 
		blk_mq_map_swqueue(q);

	}



	list_for_each_entry(q, &set->tag_list, tag_set_list)

		queue_update_fair_tag_sharing(q);



reregister:

	list_for_each_entry(q, &set->tag_list, tag_set_list) {

		blk_mq_sysfs_register_hctxs(q);

block/blk-mq.h

+2 −1
Original line number Diff line number Diff line
@@ -393,7 +393,8 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, 
{

	unsigned int depth, users;



	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))

	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||

	    (hctx->flags & BLK_MQ_F_DISABLE_FAIR_TAG_SHARING))

		return true;



	/*

drivers/scsi/scsi_lib.c

+3 −0
Original line number Diff line number Diff line
@@ -1958,6 +1958,7 @@ static const struct blk_mq_ops scsi_mq_ops = { 
	.get_rq_budget_token = scsi_mq_get_rq_budget_token,

};



#define FAIR_TAG_SHARING_THRESHOLD 128

int scsi_mq_setup_tags(struct Scsi_Host *shost)

{

	unsigned int cmd_size, sgl_size;
@@ -1983,6 +1984,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) 
	tag_set->flags = BLK_MQ_F_SHOULD_MERGE;

	tag_set->flags |=

		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);

	if (tag_set->queue_depth <= FAIR_TAG_SHARING_THRESHOLD)

		tag_set->flags |= BLK_MQ_F_DISABLE_FAIR_TAG_SHARING;

	if (shost->queuecommand_may_block)

		tag_set->flags |= BLK_MQ_F_BLOCKING;

	tag_set->driver_data = shost;

drivers/scsi/scsi_sysfs.c

+39 −0
Original line number Diff line number Diff line
@@ -403,6 +403,44 @@ show_nr_hw_queues(struct device *dev, struct device_attribute *attr, char *buf) 
}

static DEVICE_ATTR(nr_hw_queues, S_IRUGO, show_nr_hw_queues, NULL);



static ssize_t

fair_sharing_show(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct Scsi_Host *shost = class_to_shost(dev);

	struct blk_mq_tag_set *tag_set = &shost->tag_set;



	return sprintf(buf, "%d\n",

		       !(tag_set->flags & BLK_MQ_F_DISABLE_FAIR_TAG_SHARING));

}



static ssize_t

fair_sharing_store(struct device *dev, struct device_attribute *attr,

		   const char *buf, size_t count)

{

	struct Scsi_Host *shost = class_to_shost(dev);

	struct blk_mq_tag_set *tag_set = &shost->tag_set;

	bool enable;

	int res = kstrtobool(buf, &enable);



	if (res < 0)

		return res;



	if (!(tag_set->flags & BLK_MQ_F_DISABLE_FAIR_TAG_SHARING) == enable)

		return count;



	mutex_lock(&tag_set->tag_list_lock);

	if (!(tag_set->flags & BLK_MQ_F_DISABLE_FAIR_TAG_SHARING) == enable)

		goto out_unlock;



	tag_set->flags ^= BLK_MQ_F_DISABLE_FAIR_TAG_SHARING;

	blk_mq_update_fair_tag_sharing(tag_set);



out_unlock:

	mutex_unlock(&tag_set->tag_list_lock);

	return count;

}

static DEVICE_ATTR_RW(fair_sharing);



static struct attribute *scsi_sysfs_shost_attrs[] = {

	&dev_attr_use_blk_mq.attr,

	&dev_attr_unique_id.attr,
@@ -421,6 +459,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = { 
	&dev_attr_host_reset.attr,

	&dev_attr_eh_deadline.attr,

	&dev_attr_nr_hw_queues.attr,

	&dev_attr_fair_sharing.attr,

	NULL

};