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From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
	Sagi Grimberg <sagi@grimberg.me>,
	Baolin Wang <baolin.wang7@gmail.com>,
	Christoph Hellwig <hch@infradead.org>,
	Douglas Anderson <dianders@chromium.org>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH V7 1/6] blk-mq: pass request queue into get/put budget callback
Date: Tue, 30 Jun 2020 18:24:56 +0800
Message-ID: <20200630102501.2238972-2-ming.lei@redhat.com> (raw)
In-Reply-To: <20200630102501.2238972-1-ming.lei@redhat.com>

blk-mq budget is abstract from scsi's device queue depth, and it is
always per-request-queue instead of hctx.

It can be quite absurd to get a budget from one hctx, then dequeue a
request from scheduler queue, and this request may not belong to this
hctx, at least for bfq and deadline.

So fix the mess and always pass request queue to get/put budget
callback.

Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq-sched.c    |  8 ++++----
 block/blk-mq.c          |  8 ++++----
 block/blk-mq.h          | 12 ++++--------
 drivers/scsi/scsi_lib.c |  8 +++-----
 include/linux/blk-mq.h  |  4 ++--
 5 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index fdcc2c1dd178..a31e281e9d31 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -108,12 +108,12 @@ static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 			break;
 		}
 
-		if (!blk_mq_get_dispatch_budget(hctx))
+		if (!blk_mq_get_dispatch_budget(q))
 			break;
 
 		rq = e->type->ops.dispatch_request(hctx);
 		if (!rq) {
-			blk_mq_put_dispatch_budget(hctx);
+			blk_mq_put_dispatch_budget(q);
 			/*
 			 * We're releasing without dispatching. Holding the
 			 * budget could have blocked any "hctx"s with the
@@ -173,12 +173,12 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 		if (!sbitmap_any_bit_set(&hctx->ctx_map))
 			break;
 
-		if (!blk_mq_get_dispatch_budget(hctx))
+		if (!blk_mq_get_dispatch_budget(q))
 			break;
 
 		rq = blk_mq_dequeue_from_ctx(hctx, ctx);
 		if (!rq) {
-			blk_mq_put_dispatch_budget(hctx);
+			blk_mq_put_dispatch_budget(q);
 			/*
 			 * We're releasing without dispatching. Holding the
 			 * budget could have blocked any "hctx"s with the
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4c3a3e1224b4..4b143c1c0c8d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1340,7 +1340,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 		rq = list_first_entry(list, struct request, queuelist);
 
 		hctx = rq->mq_hctx;
-		if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) {
+		if (!got_budget && !blk_mq_get_dispatch_budget(q)) {
 			blk_mq_put_driver_tag(rq);
 			no_budget_avail = true;
 			break;
@@ -1355,7 +1355,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 			 * we'll re-run it below.
 			 */
 			if (!blk_mq_mark_tag_wait(hctx, rq)) {
-				blk_mq_put_dispatch_budget(hctx);
+				blk_mq_put_dispatch_budget(q);
 				/*
 				 * For non-shared tags, the RESTART check
 				 * will suffice.
@@ -2003,11 +2003,11 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 	if (q->elevator && !bypass_insert)
 		goto insert;
 
-	if (!blk_mq_get_dispatch_budget(hctx))
+	if (!blk_mq_get_dispatch_budget(q))
 		goto insert;
 
 	if (!blk_mq_get_driver_tag(rq)) {
-		blk_mq_put_dispatch_budget(hctx);
+		blk_mq_put_dispatch_budget(q);
 		goto insert;
 	}
 
diff --git a/block/blk-mq.h b/block/blk-mq.h
index a62ca18b5bde..462890966758 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -179,20 +179,16 @@ unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
 void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
 			 unsigned int inflight[2]);
 
-static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx)
+static inline void blk_mq_put_dispatch_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
-
 	if (q->mq_ops->put_budget)
-		q->mq_ops->put_budget(hctx);
+		q->mq_ops->put_budget(q);
 }
 
-static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
+static inline bool blk_mq_get_dispatch_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
-
 	if (q->mq_ops->get_budget)
-		return q->mq_ops->get_budget(hctx);
+		return q->mq_ops->get_budget(q);
 	return true;
 }
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6ca91d09eca1..534b85e87c80 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1597,17 +1597,15 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
 	blk_mq_complete_request(cmd->request);
 }
 
-static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
+static void scsi_mq_put_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
 	struct scsi_device *sdev = q->queuedata;
 
 	atomic_dec(&sdev->device_busy);
 }
 
-static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
+static bool scsi_mq_get_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
 	struct scsi_device *sdev = q->queuedata;
 
 	return scsi_dev_queue_ready(q, sdev);
@@ -1674,7 +1672,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (scsi_target(sdev)->can_queue > 0)
 		atomic_dec(&scsi_target(sdev)->target_busy);
 out_put_budget:
-	scsi_mq_put_budget(hctx);
+	scsi_mq_put_budget(q);
 	switch (ret) {
 	case BLK_STS_OK:
 		break;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 1641ec6cd7e5..e19efe43b57e 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -270,8 +270,8 @@ struct blk_mq_queue_data {
 typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
 		const struct blk_mq_queue_data *);
 typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
-typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
-typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
+typedef bool (get_budget_fn)(struct request_queue *);
+typedef void (put_budget_fn)(struct request_queue *);
 typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
 typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
 typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
-- 
2.25.2


  reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30 10:24 [PATCH V7 0/6] blk-mq: support batching dispatch from scheduler Ming Lei
2020-06-30 10:24 ` Ming Lei [this message]
2020-06-30 10:24 ` [PATCH V7 2/6] blk-mq: pass hctx to blk_mq_dispatch_rq_list Ming Lei
2020-06-30 10:24 ` [PATCH V7 3/6] blk-mq: move getting driver tag and budget into one helper Ming Lei
2020-06-30 10:24 ` [PATCH V7 4/6] blk-mq: remove dead check from blk_mq_dispatch_rq_list Ming Lei
2020-06-30 10:25 ` [PATCH V7 5/6] blk-mq: pass obtained budget count to blk_mq_dispatch_rq_list Ming Lei
2020-06-30 10:25 ` [PATCH V7 6/6] blk-mq: support batching dispatch in case of io Ming Lei
2020-06-30 13:40   ` Christoph Hellwig
2020-06-30 14:03 ` [PATCH V7 0/6] blk-mq: support batching dispatch from scheduler Jens Axboe

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