| Message ID | 1628519378-211232-4-git-send-email-john.garry@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-mq: Reduce static requests memory footprint for shared sbitmap | expand |
On Mon, Aug 09, 2021 at 10:29:30PM +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> Reviewed-by: Ming Lei <ming.lei@redhat.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c index ae28f470893c..0e4825ca9869 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 +3641,13 @@ 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); + } } blk_mq_unquiesce_queue(q);
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 | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)