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authorPaolo Valente <paolo.valente@linaro.org>2019-01-29 12:06:36 +0100
committerJens Axboe <axboe@kernel.dk>2019-01-31 12:50:24 -0700
commitb3c3498112ffafa5f613bb482f9723996bfd5e4f (patch)
treec86fd92e803cb558902ae247027934cb2015fa62 /block
parenta3c92560324bd616deaecb6842b2a0337a80ad8b (diff)
block, bfq: port commit "cfq-iosched: improve hw_tag detection"
The original commit is commit 1a1238a7dd48 ("cfq-iosched: improve hw_tag detection") and has the following commit message: If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bfq-iosched.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 48b579032d14..2ab53d93ba12 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4786,6 +4786,8 @@ static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx,
static void bfq_update_hw_tag(struct bfq_data *bfqd)
{
+ struct bfq_queue *bfqq = bfqd->in_service_queue;
+
bfqd->max_rq_in_driver = max_t(int, bfqd->max_rq_in_driver,
bfqd->rq_in_driver);
@@ -4801,6 +4803,17 @@ static void bfq_update_hw_tag(struct bfq_data *bfqd)
if (bfqd->rq_in_driver + bfqd->queued <= BFQ_HW_QUEUE_THRESHOLD)
return;
+ /*
+ * If active queue hasn't enough requests and can idle, bfq might not
+ * dispatch sufficient requests to hardware. Don't zero hw_tag in this
+ * case
+ */
+ if (bfqq && bfq_bfqq_has_short_ttime(bfqq) &&
+ bfqq->dispatched + bfqq->queued[0] + bfqq->queued[1] <
+ BFQ_HW_QUEUE_THRESHOLD &&
+ bfqd->rq_in_driver < BFQ_HW_QUEUE_THRESHOLD)
+ return;
+
if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES)
return;