[PATCH] blk-iocos: fix inuse clamp when iocg deactivate or free

[Chengming Zhou]

For an active leaf node, its inuse shouldn't be zero or exceed
its active, but it's not true when deactivate idle iocg or delete
iocg in ioc_pd_free().

Although inuse of 1 is very small, it could cause noticeable hwi
decrease in the long running server. So we'd better fix it.

And check iocg->child_active_sum is enough for inner iocg, remove
the needless list_empty check by the way.

Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
 block/blk-iocost.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 2570732b92d1..84374ebcc402 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1073,11 +1073,11 @@ static void __propagate_weights(struct ioc_gq *iocg, u32 active, u32 inuse,
 	 * @active. An active internal node's inuse is solely determined by the
 	 * inuse to active ratio of its children regardless of @inuse.
 	 */
-	if (list_empty(&iocg->active_list) && iocg->child_active_sum) {
+	if (iocg->child_active_sum) {
 		inuse = DIV64_U64_ROUND_UP(active * iocg->child_inuse_sum,
 					   iocg->child_active_sum);
 	} else {
-		inuse = clamp_t(u32, inuse, 1, active);
+		inuse = clamp_t(u32, inuse, 0, active);
 	}
 
 	iocg->last_inuse = iocg->inuse;
-- 
2.36.1