[PATCH 05/20] block, bfq: recover the "service hole" if enough budget is left

[Kemeng Shi]

If budget left is less than budget need by next request, the activated bfqq
will be expired if it preempts the in-service queue. Avoid to cause useless
overhead to check budget left is enough for next request.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxx>
---
 block/bfq-iosched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index be69b0e061f7..f4b4ba05f804 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1623,7 +1623,7 @@ static bool bfq_bfqq_update_budg_for_activation(struct bfq_data *bfqd,
 	 * service. This would only cause useless overhead.
 	 */
 	if (bfq_bfqq_non_blocking_wait_rq(bfqq) && arrived_in_time &&
-	    bfq_bfqq_budget_left(bfqq) > 0) {
+	    bfq_bfqq_budget_left(bfqq) >= bfq_serv_to_charge(bfqq->next_rq, bfqq)) {
 		/*
 		 * We do not clear the flag non_blocking_wait_rq here, as
 		 * the latter is used in bfq_activate_bfqq to signal
-- 
2.30.0