diff mbox

[4/9] blk-mq: only run hw queues for blk-mq

Message ID 20170831172728.15817-5-ming.lei@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ming Lei Aug. 31, 2017, 5:27 p.m. UTC 
This patch just makes it explicitely.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Johannes Thumshirn Sept. 1, 2017, 8:16 a.m. UTC | #1 
Hi Ming,

On Fri, Sep 01, 2017 at 01:27:23AM +0800, Ming Lei wrote:
> -		blk_mq_run_hw_queues(q, false);
> +		if (q->mq_ops)
> +			blk_mq_run_hw_queues(q, false);

What speaks against putting the if (q->mq_ops) directly into
blk_mq_run_hw_queues() so we can't accidently call it from the sq path?

Just an idea, no hard preferences here.

Byte,
	Johannes
Ming Lei Sept. 1, 2017, 12:33 p.m. UTC | #2 
On Fri, Sep 01, 2017 at 10:16:34AM +0200, Johannes Thumshirn wrote:
> Hi Ming,
> 
> On Fri, Sep 01, 2017 at 01:27:23AM +0800, Ming Lei wrote:
> > -		blk_mq_run_hw_queues(q, false);
> > +		if (q->mq_ops)
> > +			blk_mq_run_hw_queues(q, false);
> 
> What speaks against putting the if (q->mq_ops) directly into
> blk_mq_run_hw_queues() so we can't accidently call it from the sq path?
> 
> Just an idea, no hard preferences here.

Given it is the only case that blk_mq_run_hw_queues() is run on
!q->mq_ops now, I suggest to check q->mq_ops outside, otherwise
it can be a bit overkill.
Johannes Thumshirn Sept. 1, 2017, 12:44 p.m. UTC | #3 
On Fri, Sep 01, 2017 at 08:33:40PM +0800, Ming Lei wrote:
> Given it is the only case that blk_mq_run_hw_queues() is run on
> !q->mq_ops now, I suggest to check q->mq_ops outside, otherwise
> it can be a bit overkill.

Fair enough,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
diff mbox

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8cf1f7cbef2b..4c532d8612e1 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -125,7 +125,8 @@  void blk_freeze_queue_start(struct request_queue *q)
 	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
 	if (freeze_depth == 1) {
 		percpu_ref_kill(&q->q_usage_counter);
-		blk_mq_run_hw_queues(q, false);
+		if (q->mq_ops)
+			blk_mq_run_hw_queues(q, false);
 	}
 }
 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);