diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2025-07-29 10:32:29 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-07-29 06:26:34 -0600 |
| commit | 5421681bc3ef13476bd9443379cd69381e8760fa (patch) | |
| tree | c93edc86cba65073358ef647a77b8066cb820786 /block/bfq-iosched.c | |
| parent | 1da67b5b1754713b8ea0c3dd847e04790cffd91f (diff) | |
blk-ioc: don't hold queue_lock for ioc_lookup_icq()
Currently issue io can grab queue_lock three times from bfq_bio_merge(),
bfq_limit_depth() and bfq_prepare_request(), the queue_lock is not
necessary if icq is already created because both queue and ioc can't be
freed before io issuing is done, hence remove the unnecessary queue_lock
and use rcu to protect radix tree lookup.
Noted this is also a prep patch to support request batch dispatching[1].
[1] https://lore.kernel.org/all/20250722072431.610354-1-yukuai1@huaweicloud.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20250729023229.2944898-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 0cb1e9873aab..f71ec0887733 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -454,17 +454,10 @@ static struct bfq_io_cq *icq_to_bic(struct io_cq *icq) */ static struct bfq_io_cq *bfq_bic_lookup(struct request_queue *q) { - struct bfq_io_cq *icq; - unsigned long flags; - if (!current->io_context) return NULL; - spin_lock_irqsave(&q->queue_lock, flags); - icq = icq_to_bic(ioc_lookup_icq(q)); - spin_unlock_irqrestore(&q->queue_lock, flags); - - return icq; + return icq_to_bic(ioc_lookup_icq(q)); } /* @@ -2457,15 +2450,8 @@ static bool bfq_bio_merge(struct request_queue *q, struct bio *bio, unsigned int nr_segs) { struct bfq_data *bfqd = q->elevator->elevator_data; - struct request *free = NULL; - /* - * bfq_bic_lookup grabs the queue_lock: invoke it now and - * store its return value for later use, to avoid nesting - * queue_lock inside the bfqd->lock. We assume that the bic - * returned by bfq_bic_lookup does not go away before - * bfqd->lock is taken. - */ struct bfq_io_cq *bic = bfq_bic_lookup(q); + struct request *free = NULL; bool ret; spin_lock_irq(&bfqd->lock); |