diff options
| -rw-r--r-- | block/blk-mq-tag.c | 12 | ||||
| -rw-r--r-- | include/linux/sbitmap.h | 7 | ||||
| -rw-r--r-- | lib/sbitmap.c | 29 |
3 files changed, 34 insertions, 14 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 336dde07b230..a4e58fc28a06 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -134,6 +134,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) ws = bt_wait_ptr(bt, data->hctx); drop_ctx = data->ctx == NULL; do { + struct sbitmap_queue *bt_prev; + /* * We're out of tags on this hardware queue, kick any * pending IO submits before going to sleep waiting for @@ -159,6 +161,7 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) if (data->ctx) blk_mq_put_ctx(data->ctx); + bt_prev = bt; io_schedule(); data->ctx = blk_mq_get_ctx(data->q); @@ -170,6 +173,15 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) bt = &tags->bitmap_tags; finish_wait(&ws->wait, &wait); + + /* + * If destination hw queue is changed, fake wake up on + * previous queue for compensating the wake up miss, so + * other allocations on previous queue won't be starved. + */ + if (bt != bt_prev) + sbitmap_queue_wake_up(bt_prev); + ws = bt_wait_ptr(bt, data->hctx); } while (1); diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index 0c4a9c242dd7..e6539536dea9 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -513,6 +513,13 @@ static inline struct sbq_wait_state *sbq_wait_ptr(struct sbitmap_queue *sbq, void sbitmap_queue_wake_all(struct sbitmap_queue *sbq); /** + * sbitmap_queue_wake_up() - Wake up some of waiters in one waitqueue + * on a &struct sbitmap_queue. + * @sbq: Bitmap queue to wake up. + */ +void sbitmap_queue_wake_up(struct sbitmap_queue *sbq); + +/** * sbitmap_queue_show() - Dump &struct sbitmap_queue information to a &struct * seq_file. * @sbq: Bitmap queue to show. diff --git a/lib/sbitmap.c b/lib/sbitmap.c index e6d7d610778d..6fdc6267f4a8 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -352,8 +352,9 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, if (sbq->wake_batch != wake_batch) { WRITE_ONCE(sbq->wake_batch, wake_batch); /* - * Pairs with the memory barrier in sbq_wake_up() to ensure that - * the batch size is updated before the wait counts. + * Pairs with the memory barrier in sbitmap_queue_wake_up() + * to ensure that the batch size is updated before the wait + * counts. */ smp_mb__before_atomic(); for (i = 0; i < SBQ_WAIT_QUEUES; i++) @@ -463,15 +464,6 @@ static bool __sbq_wake_up(struct sbitmap_queue *sbq) unsigned int wake_batch; int wait_cnt; - /* - * Pairs with the memory barrier in set_current_state() to ensure the - * proper ordering of clear_bit()/waitqueue_active() in the waker and - * test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the - * waiter. See the comment on waitqueue_active(). This is __after_atomic - * because we just did clear_bit_unlock() in the caller. - */ - smp_mb__after_atomic(); - ws = sbq_wake_ptr(sbq); if (!ws) return false; @@ -507,17 +499,26 @@ static bool __sbq_wake_up(struct sbitmap_queue *sbq) return false; } -static void sbq_wake_up(struct sbitmap_queue *sbq) +void sbitmap_queue_wake_up(struct sbitmap_queue *sbq) { while (__sbq_wake_up(sbq)) ; } +EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up); void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, unsigned int cpu) { sbitmap_clear_bit_unlock(&sbq->sb, nr); - sbq_wake_up(sbq); + /* + * Pairs with the memory barrier in set_current_state() to ensure the + * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker + * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the + * waiter. See the comment on waitqueue_active(). + */ + smp_mb__after_atomic(); + sbitmap_queue_wake_up(sbq); + if (likely(!sbq->round_robin && nr < sbq->sb.depth)) *per_cpu_ptr(sbq->alloc_hint, cpu) = nr; } @@ -529,7 +530,7 @@ void sbitmap_queue_wake_all(struct sbitmap_queue *sbq) /* * Pairs with the memory barrier in set_current_state() like in - * sbq_wake_up(). + * sbitmap_queue_wake_up(). */ smp_mb(); wake_index = atomic_read(&sbq->wake_index); |