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From: Ming Lei <ming.lei@redhat.com>
To: John Garry <john.garry@huawei.com>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
kashyap.desai@broadcom.com, hare@suse.de
Subject: Re: [PATCH 3/9] blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests()
Date: Tue, 20 Jul 2021 15:50:28 +0800 [thread overview]
Message-ID: <YPaARLPPZxcbat8H@T590> (raw)
In-Reply-To: <1626275195-215652-4-git-send-email-john.garry@huawei.com>
On Wed, Jul 14, 2021 at 11:06:29PM +0800, John Garry wrote:
> For shared sbitmap, if the call to blk_mq_tag_update_depth() was
> successful for any hctx when hctx->sched_tags is not set, then it would be
> successful for all (due to nature in which blk_mq_tag_update_depth()
> fails).
>
> As such, there is no need to call blk_mq_tag_resize_shared_sbitmap() for
> each hctx. So relocate the call until after the hctx iteration under the
> !q->elevator check, which is equivalent (to !hctx->sched_tags).
>
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
> block/blk-mq.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index ae28f470893c..56e3c6fdba60 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -3624,8 +3624,6 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
> if (!hctx->sched_tags) {
> ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
> false);
> - if (!ret && blk_mq_is_sbitmap_shared(set->flags))
> - blk_mq_tag_resize_shared_sbitmap(set, nr);
> } else {
> ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
> nr, true);
> @@ -3643,9 +3641,14 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
> }
> if (!ret) {
> q->nr_requests = nr;
> - if (q->elevator && blk_mq_is_sbitmap_shared(set->flags))
> - sbitmap_queue_resize(&q->sched_bitmap_tags,
> - nr - set->reserved_tags);
> + if (blk_mq_is_sbitmap_shared(set->flags)) {
> + if (q->elevator) {
> + sbitmap_queue_resize(&q->sched_bitmap_tags,
> + nr - set->reserved_tags);
> + } else {
> + blk_mq_tag_resize_shared_sbitmap(set, nr);
> + }
The above two {} can be removed.
--
Ming
next prev parent reply other threads:[~2021-07-20 7:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 15:06 [PATCH 0/9] blk-mq: Reduce static requests memory footprint for shared sbitmap John Garry
2021-07-14 15:06 ` [PATCH 1/9] blk-mq: Change rqs check in blk_mq_free_rqs() John Garry
2021-07-20 7:35 ` Ming Lei
2021-07-14 15:06 ` [PATCH 2/9] block: Rename BLKDEV_MAX_RQ -> BLKDEV_DEFAULT_RQ John Garry
2021-07-20 7:44 ` Ming Lei
2021-07-14 15:06 ` [PATCH 3/9] blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests() John Garry
2021-07-20 7:50 ` Ming Lei [this message]
2021-07-20 8:06 ` John Garry
2021-07-14 15:06 ` [PATCH 4/9] blk-mq: Add blk_mq_tag_resize_sched_shared_sbitmap() John Garry
2021-07-20 7:57 ` Ming Lei
2021-07-20 8:08 ` John Garry
2021-07-14 15:06 ` [PATCH 5/9] blk-mq: Invert check in blk_mq_update_nr_requests() John Garry
2021-07-14 15:06 ` [PATCH RFC 6/9] blk-mq: Refactor blk_mq_{alloc,free}_rqs John Garry
2021-07-14 15:06 ` [PATCH RFC 7/9] blk-mq: Allocate per tag set static rqs for shared sbitmap John Garry
2021-07-14 15:06 ` [PATCH 8/9] blk-mq: Allocate per request queue " John Garry
2021-07-14 15:06 ` [PATCH 9/9] blk-mq: Clear mappings for shared sbitmap sched static rqs John Garry
2021-07-20 15:22 ` [PATCH 0/9] blk-mq: Reduce static requests memory footprint for shared sbitmap Ming Lei
2021-07-20 17:05 ` John Garry
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