From: Chunguang Xu <brookxu@xxxxxxxxxxx>
CLASS_RT is more sensitive to latency, and IO injection
will increase the CLASS_RT latency. For this reason,
consider prohibiting the injection of async queue for
CLASS_RT, and only the waker queue and other active
queues belonging to CLASS_RT are allowed to inject. In
this way, for CLASS_RT, both the advantages of inject
and IO latency can be maintained.
Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx>
---
block/bfq-iosched.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 8af73473c45c..a5f13589df79 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1965,6 +1965,9 @@ static void bfq_check_waker(struct bfq_data *bfqd, struct bfq_queue *bfqq,
bfqd->last_completed_rq_bfqq == bfqq->waker_bfqq)
return;
+ if (bfq_class_rt(bfqq) && !bfq_class_rt(bfqd->last_completed_rq_bfqq))
+ return;
+
if (bfqd->last_completed_rq_bfqq !=
bfqq->tentative_waker_bfqq) {
/*
@@ -4391,6 +4394,9 @@ bfq_choose_bfqq_for_injection(struct bfq_data *bfqd)
else
limit = in_serv_bfqq->inject_limit;
+ if (bfq_class_rt(in_serv_bfqq) && !bfq_class_rt(bfqq))
+ continue;
+
if (bfqd->rq_in_driver < limit) {
bfqd->rqs_injected = true;
return bfqq;
@@ -4565,7 +4571,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd)
* may not be minimized, because the waker queue may
* happen to be served only after other queues.
*/
- if (async_bfqq &&
+ if (async_bfqq && !bfq_class_rt(bfqq) &&
icq_to_bic(async_bfqq->next_rq->elv.icq) == bfqq->bic &&
bfq_serv_to_charge(async_bfqq->next_rq, async_bfqq) <=
bfq_bfqq_budget_left(async_bfqq))
--
2.30.0
