Commit 68497092 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: make queue stat accounting a reference 



kyber turns on IO statistics when it is loaded on a queue, which means
that even if kyber is then later unloaded, we're still stuck with stats
enabled on the queue.

Change the account enabled from a bool to an int, and pair the enable call
with the equivalent disable call. This ensures that stats gets turned off
again appropriately.

Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0ba4566c

block/blk-stat.c

+16 −5
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
struct blk_queue_stats {

	struct list_head callbacks;

	spinlock_t lock;

	bool enable_accounting;

	int accounting;

};



void blk_rq_stat_init(struct blk_rq_stat *stat)
@@ -161,7 +161,7 @@ void blk_stat_remove_callback(struct request_queue *q, 


	spin_lock_irqsave(&q->stats->lock, flags);

	list_del_rcu(&cb->list);

	if (list_empty(&q->stats->callbacks) && !q->stats->enable_accounting)

	if (list_empty(&q->stats->callbacks) && !q->stats->accounting)

		blk_queue_flag_clear(QUEUE_FLAG_STATS, q);

	spin_unlock_irqrestore(&q->stats->lock, flags);
@@ -184,12 +184,23 @@ void blk_stat_free_callback(struct blk_stat_callback *cb) 
		call_rcu(&cb->rcu, blk_stat_free_callback_rcu);

}



void blk_stat_disable_accounting(struct request_queue *q)

{

	unsigned long flags;



	spin_lock_irqsave(&q->stats->lock, flags);

	if (!--q->stats->accounting)

		blk_queue_flag_clear(QUEUE_FLAG_STATS, q);

	spin_unlock_irqrestore(&q->stats->lock, flags);

}

EXPORT_SYMBOL_GPL(blk_stat_disable_accounting);



void blk_stat_enable_accounting(struct request_queue *q)

{

	unsigned long flags;



	spin_lock_irqsave(&q->stats->lock, flags);

	q->stats->enable_accounting = true;

	if (!q->stats->accounting++)

		blk_queue_flag_set(QUEUE_FLAG_STATS, q);

	spin_unlock_irqrestore(&q->stats->lock, flags);

}
@@ -205,7 +216,7 @@ struct blk_queue_stats *blk_alloc_queue_stats(void) 


	INIT_LIST_HEAD(&stats->callbacks);

	spin_lock_init(&stats->lock);

	stats->enable_accounting = false;

	stats->accounting = 0;



	return stats;

}

block/blk-stat.h

+1 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ void blk_stat_add(struct request *rq, u64 now); 


/* record time/size info in request but not add a callback */

void blk_stat_enable_accounting(struct request_queue *q);

void blk_stat_disable_accounting(struct request_queue *q);



/**

 * blk_stat_alloc_callback() - Allocate a block statistics callback.

block/kyber-iosched.c

+1 −0
Original line number Diff line number Diff line
@@ -433,6 +433,7 @@ static void kyber_exit_sched(struct elevator_queue *e) 
	int i;



	del_timer_sync(&kqd->timer);

	blk_stat_disable_accounting(kqd->q);



	for (i = 0; i < KYBER_NUM_DOMAINS; i++)

		sbitmap_queue_free(&kqd->domain_tokens[i]);