From 68497092bde9f53e35cafeb52fa9a267ebe0d9b1 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 14 Dec 2021 17:23:05 -0700 Subject: [PATCH] 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: Omar Sandoval Signed-off-by: Jens Axboe --- block/blk-stat.c | 21 ++++++++++++++++----- block/blk-stat.h | 1 + block/kyber-iosched.c | 1 + 3 files changed, 18 insertions(+), 5 deletions(-) diff --git a/block/blk-stat.c b/block/blk-stat.c index efb2a80db906..2ea01b5c1aca 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -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); @@ -184,13 +184,24 @@ 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; - blk_queue_flag_set(QUEUE_FLAG_STATS, q); + if (!q->stats->accounting++) + blk_queue_flag_set(QUEUE_FLAG_STATS, q); spin_unlock_irqrestore(&q->stats->lock, flags); } EXPORT_SYMBOL_GPL(blk_stat_enable_accounting); @@ -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; } diff --git a/block/blk-stat.h b/block/blk-stat.h index 58f029af49e5..17e1eb4ec7e2 100644 --- a/block/blk-stat.h +++ b/block/blk-stat.h @@ -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. diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c index fdd74a4df56f..70ff2a599ef6 100644 --- a/block/kyber-iosched.c +++ b/block/kyber-iosched.c @@ -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]);