Thread (9 messages) 9 messages, 3 authors, 2019-09-16
STALE2485d

[PATCH 4/4] block, bfq: push up injection only after setting service time

From: Paolo Valente <hidden>
Date: 2019-08-22 15:21:14
Also in: lkml
Subsystem: bfq i/o scheduler, block layer, the rest · Maintainers: Yu Kuai, Jens Axboe, Linus Torvalds

If equal to 0, the injection limit for a bfq_queue is pushed to 1
after a first sample of the total service time of the I/O requests of
the queue is computed (to allow injection to start). Yet, because of a
mistake in the branch that performs this action, the push may happen
also in some other case. This commit fixes this issue.

Signed-off-by: Paolo Valente <redacted>
---
 block/bfq-iosched.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index ddac93e910fa..0319d6339822 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5823,12 +5823,14 @@ static void bfq_update_inject_limit(struct bfq_data *bfqd,
 	 */
 	if ((bfqq->last_serv_time_ns == 0 && bfqd->rq_in_driver == 1) ||
 	    tot_time_ns < bfqq->last_serv_time_ns) {
+		if (bfqq->last_serv_time_ns == 0) {
+			/*
+			 * Now we certainly have a base value: make sure we
+			 * start trying injection.
+			 */
+			bfqq->inject_limit = max_t(unsigned int, 1, old_limit);
+		}
 		bfqq->last_serv_time_ns = tot_time_ns;
-		/*
-		 * Now we certainly have a base value: make sure we
-		 * start trying injection.
-		 */
-		bfqq->inject_limit = max_t(unsigned int, 1, old_limit);
 	} else if (!bfqd->rqs_injected && bfqd->rq_in_driver == 1)
 		/*
 		 * No I/O injected and no request still in service in
-- 
2.20.1
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