On 9/8/25 11:45 AM, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> No functional changes are intended, make code cleaner and prepare to fix
> the grow case in following patches.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> ---
> block/blk-mq.c | 28 ++++++++++++++++------------
> 1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 1ff6370f7314..82fa81036115 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -4931,21 +4931,25 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
> blk_mq_tag_update_sched_shared_tags(q);
> else
> blk_mq_tag_resize_shared_tags(set, nr);
> - } else {
> + } else if (!q->elevator) {
> queue_for_each_hw_ctx(q, hctx, i) {
> if (!hctx->tags)
> continue;
> - /*
> - * If we're using an MQ scheduler, just update the
> - * scheduler queue depth. This is similar to what the
> - * old code would do.
> - */
> - if (hctx->sched_tags)
> - ret = blk_mq_tag_update_depth(hctx,
> - &hctx->sched_tags, nr);
> - else
> - ret = blk_mq_tag_update_depth(hctx,
> - &hctx->tags, nr);
> + sbitmap_queue_resize(&hctx->tags->bitmap_tags,
> + nr - hctx->tags->nr_reserved_tags);
> + }
> + } else if (nr <= q->elevator->et->nr_requests) {
> + queue_for_each_hw_ctx(q, hctx, i) {
> + if (!hctx->sched_tags)
> + continue;
> + sbitmap_queue_resize(&hctx->sched_tags->bitmap_tags,
> + nr - hctx->sched_tags->nr_reserved_tags);
> + }
> + } else {
> + queue_for_each_hw_ctx(q, hctx, i) {
> + if (!hctx->sched_tags)
> + continue;
> + blk_mq_tag_update_depth(hctx, &hctx->sched_tags, nr);
> if (ret)
> goto out;
> }
The above code is good however can this be bit simplified?
It's a bit difficult to follow through all nesting and so
could it be simplified as below:
if (shared-tags) {
if (elevator)
// resize sched-shared-tags bitmap
else
// resize shared-tags bitmap
} else {
// non-shared tags
if (elevator) {
if (new-depth-is-less-than-the-current-depth)
// resize sched-tags bitmap
else
// handle sched tags grow
} else
// resize tags bitmap
}
Thanks,
--Nilay
