[PATCH 3/4] blk-throttle: cleanup tg_update_disptime()

From: Yu Kuai
Date: Mon Aug 22 2022 - 21:27:14 EST


From: Yu Kuai <yukuai3@xxxxxxxxxx>

tg_update_disptime() only need to adjust postion for 'tg' in
'parent_sq', there is no need to call throtl_enqueue/dequeue_tg(),
since they will set/clear flag THROTL_TG_PENDING and increase/decrease
nr_pending, which is useless. By the way, clear the flag/decrease
nr_pending while there are still throttled bios is not good for debugging.

There are no functional changes.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/blk-throttle.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 64002435fa43..47142a1dd102 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -520,7 +520,6 @@ static void throtl_rb_erase(struct rb_node *n,
{
rb_erase_cached(n, &parent_sq->pending_tree);
RB_CLEAR_NODE(n);
- --parent_sq->nr_pending;
}

static void update_min_dispatch_time(struct throtl_service_queue *parent_sq)
@@ -572,7 +571,11 @@ static void throtl_enqueue_tg(struct throtl_grp *tg)
static void throtl_dequeue_tg(struct throtl_grp *tg)
{
if (tg->flags & THROTL_TG_PENDING) {
- throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq);
+ struct throtl_service_queue *parent_sq =
+ tg->service_queue.parent_sq;
+
+ throtl_rb_erase(&tg->rb_node, parent_sq);
+ --parent_sq->nr_pending;
tg->flags &= ~THROTL_TG_PENDING;
}
}
@@ -990,9 +993,9 @@ static void tg_update_disptime(struct throtl_grp *tg)
disptime = jiffies + min_wait;

/* Update dispatch time */
- throtl_dequeue_tg(tg);
+ throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq);
tg->disptime = disptime;
- throtl_enqueue_tg(tg);
+ tg_service_queue_add(tg);

/* see throtl_add_bio_tg() */
tg->flags &= ~THROTL_TG_WAS_EMPTY;
--
2.31.1