* [PATCH] blk-mq: don't commit_rqs() if none were queued
@ 2020-04-06 18:13 Keith Busch
2020-04-06 19:44 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Keith Busch @ 2020-04-06 18:13 UTC (permalink / raw)
To: linux-block, axboe; +Cc: Keith Busch
Unburden the drivers from checking if a call to commit_rqs() is valid by
not calling it when there are no requests to commit.
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
block/blk-mq.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6291ceedee4..8e56884fd2e9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1289,7 +1289,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
* the driver there was more coming, but that turned out to
* be a lie.
*/
- if (q->mq_ops->commit_rqs)
+ if (q->mq_ops->commit_rqs && queued)
q->mq_ops->commit_rqs(hctx);
spin_lock(&hctx->lock);
@@ -1911,6 +1911,8 @@ blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
struct list_head *list)
{
+ int queued = 0;
+
while (!list_empty(list)) {
blk_status_t ret;
struct request *rq = list_first_entry(list, struct request,
@@ -1926,7 +1928,8 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
break;
}
blk_mq_end_request(rq, ret);
- }
+ } else
+ queued++;
}
/*
@@ -1934,7 +1937,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
* the driver there was more coming, but that turned out to
* be a lie.
*/
- if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs)
+ if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs && queued)
hctx->queue->mq_ops->commit_rqs(hctx);
}
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] blk-mq: don't commit_rqs() if none were queued
2020-04-06 18:13 [PATCH] blk-mq: don't commit_rqs() if none were queued Keith Busch
@ 2020-04-06 19:44 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2020-04-06 19:44 UTC (permalink / raw)
To: Keith Busch, linux-block
On 4/6/20 11:13 AM, Keith Busch wrote:
> Unburden the drivers from checking if a call to commit_rqs() is valid by
> not calling it when there are no requests to commit.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
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