diff mbox series

[V2,5/6] blk-mq: pass obtained budget count to blk_mq_dispatch_rq_list

Message ID 20200525093807.805155-6-ming.lei@redhat.com (mailing list archive)
State New, archived
Headers show
Series blk-mq: support batching dispatch from scheduler | expand

Commit Message

Ming Lei May 25, 2020, 9:38 a.m. UTC 
Pass obtained budget count to blk_mq_dispatch_rq_list(), and prepare
for supporting fully batching submission.

With the obtained budget count, it is easier to put extra budgets
in case of .queue_rq failure.

Meantime remove the old 'got_budget' parameter.

Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq-sched.c |  8 ++++----
 block/blk-mq.c       | 13 +++++++++----
 block/blk-mq.h       |  3 ++-
 3 files changed, 15 insertions(+), 9 deletions(-)

Comments

Johannes Thumshirn May 25, 2020, 11:01 a.m. UTC | #1 
On 25/05/2020 11:39, Ming Lei wrote:
>  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
> -			     bool got_budget)
> +			     unsigned int nr_budgets)

I would probably just call it budget instead of nr_budgets.
Ming Lei May 25, 2020, 1:48 p.m. UTC | #2 
On Mon, May 25, 2020 at 11:01:29AM +0000, Johannes Thumshirn wrote:
> On 25/05/2020 11:39, Ming Lei wrote:
> >  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
> > -			     bool got_budget)
> > +			     unsigned int nr_budgets)
> 
> I would probably just call it budget instead of nr_budgets.
> 

It was named as 'budget' or 'budgets', but Christoph suggested to rename
it as 'nr_budgets'.

Thanks, 
Ming
Johannes Thumshirn May 25, 2020, 3:51 p.m. UTC | #3 
On 25/05/2020 15:48, Ming Lei wrote:
> On Mon, May 25, 2020 at 11:01:29AM +0000, Johannes Thumshirn wrote:
>> On 25/05/2020 11:39, Ming Lei wrote:
>>>  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
>>> -			     bool got_budget)
>>> +			     unsigned int nr_budgets)
>>
>> I would probably just call it budget instead of nr_budgets.
>>
> 
> It was named as 'budget' or 'budgets', but Christoph suggested to rename
> it as 'nr_budgets'.

Hm ok then I guess
diff mbox series

Patch

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 632c6f8b63f7..4c72073830f3 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -130,7 +130,7 @@  static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 		 * in blk_mq_dispatch_rq_list().
 		 */
 		list_add(&rq->queuelist, &rq_list);
-	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
+	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, 1));
 
 	return ret;
 }
@@ -198,7 +198,7 @@  static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 		/* round robin for fair dispatch */
 		ctx = blk_mq_next_ctx(hctx, rq->mq_ctx);
 
-	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
+	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, 1));
 
 	WRITE_ONCE(hctx->dispatch_from, ctx);
 	return ret;
@@ -238,7 +238,7 @@  static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 	 */
 	if (!list_empty(&rq_list)) {
 		blk_mq_sched_mark_restart_hctx(hctx);
-		if (blk_mq_dispatch_rq_list(hctx, &rq_list, false)) {
+		if (blk_mq_dispatch_rq_list(hctx, &rq_list, 0)) {
 			if (has_sched_dispatch)
 				ret = blk_mq_do_dispatch_sched(hctx);
 			else
@@ -251,7 +251,7 @@  static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 		ret = blk_mq_do_dispatch_ctx(hctx);
 	} else {
 		blk_mq_flush_busy_ctxs(hctx, &rq_list);
-		blk_mq_dispatch_rq_list(hctx, &rq_list, false);
+		blk_mq_dispatch_rq_list(hctx, &rq_list, 0);
 	}
 
 	return ret;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a368eeb9d378..3f672b2662a9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1256,7 +1256,8 @@  static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
 		 */
 		if (!blk_mq_mark_tag_wait(hctx, rq)) {
 			/* budget is always obtained before getting tag */
-			blk_mq_put_dispatch_budget(rq->q);
+			if (ask_budget)
+				blk_mq_put_dispatch_budget(rq->q);
 			return PREP_DISPATCH_NO_TAG;
 		}
 	}
@@ -1268,7 +1269,7 @@  static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
  * Returns true if we did some work AND can potentially do more.
  */
 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
-			     bool got_budget)
+			     unsigned int nr_budgets)
 {
 	enum prep_dispatch prep;
 	struct request_queue *q = hctx->queue;
@@ -1280,7 +1281,7 @@  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
 	if (list_empty(list))
 		return false;
 
-	WARN_ON(!list_is_singular(list) && got_budget);
+	WARN_ON(!list_is_singular(list) && nr_budgets);
 
 	/*
 	 * Now process all the entries, sending them to the driver.
@@ -1292,7 +1293,7 @@  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
 		rq = list_first_entry(list, struct request, queuelist);
 
 		WARN_ON_ONCE(hctx != rq->mq_hctx);
-		prep = blk_mq_prep_dispatch_rq(rq, !got_budget);
+		prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
 		if (prep != PREP_DISPATCH_OK)
 			break;
 
@@ -1349,7 +1350,11 @@  bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
 		bool needs_restart;
 		bool no_tag = false;
 		bool no_budget_avail = false;
+		unsigned i = 0;
 
+		/* release got budgets */
+		while (i++ < nr_budgets)
+			blk_mq_put_dispatch_budget(hctx->queue);
 		/*
 		 * For non-shared tags, the RESTART check
 		 * will suffice.
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 9c0e93d4fe38..97d39a63353a 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -40,7 +40,8 @@  struct blk_mq_ctx {
 void blk_mq_exit_queue(struct request_queue *q);
 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
 void blk_mq_wake_waiters(struct request_queue *q);
-bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *, bool);
+bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *,
+			     unsigned int);
 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
 				bool kick_requeue_list);
 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);