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From: Bart Van Assche <bvanassche@acm.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Bart Van Assche <bvanassche@acm.org>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Hannes Reinecke <hare@suse.de>, Ming Lei <ming.lei@redhat.com>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Himanshu Madhani <himanshu.madhani@oracle.com>
Subject: [PATCH 12/14] block/mq-deadline: Add I/O priority support
Date: Tue,  8 Jun 2021 16:07:01 -0700	[thread overview]
Message-ID: <20210608230703.19510-13-bvanassche@acm.org> (raw)
In-Reply-To: <20210608230703.19510-1-bvanassche@acm.org>

Maintain one dispatch list and FIFO one list per I/O priority class: RT, BE
and IDLE. Maintain statistics for each priority level. Split the debugfs
attributes per priority level as follows:

$ ls /sys/kernel/debug/block/.../sched/
async_depth  dispatch2        read_next_rq      write2_fifo_list
batching     read0_fifo_list  starved           write_next_rq
dispatch0    read1_fifo_list  write0_fifo_list
dispatch1    read2_fifo_list  write1_fifo_list

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/mq-deadline.c | 355 ++++++++++++++++++++++++++++++++++----------
 1 file changed, 279 insertions(+), 76 deletions(-)

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index a7d0584437d1..776ff49713c3 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -42,16 +42,40 @@ enum dd_data_dir {
 
 enum { DD_DIR_COUNT = 2 };
 
+enum dd_prio {
+	DD_RT_PRIO	= 0,
+	DD_BE_PRIO	= 1,
+	DD_IDLE_PRIO	= 2,
+	DD_PRIO_MAX	= 2,
+};
+
+enum { DD_PRIO_COUNT = 3 };
+
+/* I/O statistics per I/O priority. */
+struct io_stats_per_prio {
+	local_t inserted;
+	local_t merged;
+	local_t dispatched;
+	local_t completed;
+};
+
+/* I/O statistics for all I/O priorities (enum dd_prio). */
+struct io_stats {
+	struct io_stats_per_prio stats[DD_PRIO_COUNT];
+};
+
 struct deadline_data {
 	/*
 	 * run time data
 	 */
 
 	/*
-	 * requests (deadline_rq s) are present on both sort_list and fifo_list
+	 * Requests are present on both sort_list[] and fifo_list[][]. The
+	 * first index of fifo_list[][] is the I/O priority class (DD_*_PRIO).
+	 * The second index is the data direction (rq_data_dir(rq)).
 	 */
 	struct rb_root sort_list[DD_DIR_COUNT];
-	struct list_head fifo_list[DD_DIR_COUNT];
+	struct list_head fifo_list[DD_PRIO_COUNT][DD_DIR_COUNT];
 
 	/*
 	 * next in sort order. read, write or both are NULL
@@ -60,6 +84,8 @@ struct deadline_data {
 	unsigned int batching;		/* number of sequential requests made */
 	unsigned int starved;		/* times reads have starved writes */
 
+	struct io_stats __percpu *stats;
+
 	/*
 	 * settings that change how the i/o scheduler behaves
 	 */
@@ -71,7 +97,42 @@ struct deadline_data {
 
 	spinlock_t lock;
 	spinlock_t zone_lock;
-	struct list_head dispatch;
+	struct list_head dispatch[DD_PRIO_COUNT];
+};
+
+/* Count one event of type 'event_type' and with I/O priority 'prio' */
+#define dd_count(dd, event_type, prio) do {				\
+	struct io_stats *io_stats = get_cpu_ptr((dd)->stats);		\
+									\
+	BUILD_BUG_ON(!__same_type((dd), struct deadline_data *));	\
+	BUILD_BUG_ON(!__same_type((prio), enum dd_prio));		\
+	local_inc(&io_stats->stats[(prio)].event_type);			\
+	put_cpu_ptr(io_stats);						\
+} while (0)
+
+/*
+ * Returns the total number of dd_count(dd, event_type, prio) calls across all
+ * CPUs. No locking or barriers since it is fine if the returned sum is slightly
+ * outdated.
+ */
+#define dd_sum(dd, event_type, prio) ({					\
+	unsigned int cpu;						\
+	u32 sum = 0;							\
+									\
+	BUILD_BUG_ON(!__same_type((dd), struct deadline_data *));	\
+	BUILD_BUG_ON(!__same_type((prio), enum dd_prio));		\
+	for_each_present_cpu(cpu)					\
+		sum += local_read(&per_cpu_ptr((dd)->stats, cpu)->	\
+				  stats[(prio)].event_type);		\
+	sum;								\
+})
+
+/* Maps an I/O priority class to a deadline scheduler priority. */
+static const enum dd_prio ioprio_class_to_prio[] = {
+	[IOPRIO_CLASS_NONE]	= DD_BE_PRIO,
+	[IOPRIO_CLASS_RT]	= DD_RT_PRIO,
+	[IOPRIO_CLASS_BE]	= DD_BE_PRIO,
+	[IOPRIO_CLASS_IDLE]	= DD_IDLE_PRIO,
 };
 
 static inline struct rb_root *
@@ -147,12 +208,31 @@ static void dd_request_merged(struct request_queue *q, struct request *req,
 	}
 }
 
+/*
+ * Returns the I/O priority class (IOPRIO_CLASS_*) that has been assigned to a
+ * request.
+ */
+static u8 dd_rq_ioclass(struct request *rq)
+{
+	return IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
+}
+
 /*
  * Callback function that is invoked after @next has been merged into @req.
  */
 static void dd_merged_requests(struct request_queue *q, struct request *req,
 			       struct request *next)
 {
+	struct deadline_data *dd = q->elevator->elevator_data;
+	const u8 ioprio_class = dd_rq_ioclass(next);
+	const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
+
+	if (next->elv.priv[0]) {
+		dd_count(dd, merged, prio);
+	} else {
+		WARN_ON_ONCE(true);
+	}
+
 	/*
 	 * if next expires before rq, assign its expire time to rq
 	 * and move into next position (next will be deleted) in fifo
@@ -189,14 +269,21 @@ deadline_move_request(struct deadline_data *dd, struct request *rq)
 	deadline_remove_request(rq->q, rq);
 }
 
+/* Number of requests queued for a given priority level. */
+static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
+{
+	return dd_sum(dd, inserted, prio) - dd_sum(dd, completed, prio);
+}
+
 /*
  * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
  * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
  */
 static inline int deadline_check_fifo(struct deadline_data *dd,
+				      enum dd_prio prio,
 				      enum dd_data_dir data_dir)
 {
-	struct request *rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
+	struct request *rq = rq_entry_fifo(dd->fifo_list[prio][data_dir].next);
 
 	/*
 	 * rq is expired!
@@ -212,15 +299,16 @@ static inline int deadline_check_fifo(struct deadline_data *dd,
  * dispatch using arrival ordered lists.
  */
 static struct request *
-deadline_fifo_request(struct deadline_data *dd, enum dd_data_dir data_dir)
+deadline_fifo_request(struct deadline_data *dd, enum dd_prio prio,
+		      enum dd_data_dir data_dir)
 {
 	struct request *rq;
 	unsigned long flags;
 
-	if (list_empty(&dd->fifo_list[data_dir]))
+	if (list_empty(&dd->fifo_list[prio][data_dir]))
 		return NULL;
 
-	rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
+	rq = rq_entry_fifo(dd->fifo_list[prio][data_dir].next);
 	if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
 		return rq;
 
@@ -229,7 +317,7 @@ deadline_fifo_request(struct deadline_data *dd, enum dd_data_dir data_dir)
 	 * an unlocked target zone.
 	 */
 	spin_lock_irqsave(&dd->zone_lock, flags);
-	list_for_each_entry(rq, &dd->fifo_list[DD_WRITE], queuelist) {
+	list_for_each_entry(rq, &dd->fifo_list[prio][DD_WRITE], queuelist) {
 		if (blk_req_can_dispatch_to_zone(rq))
 			goto out;
 	}
@@ -245,7 +333,8 @@ deadline_fifo_request(struct deadline_data *dd, enum dd_data_dir data_dir)
  * dispatch using sector position sorted lists.
  */
 static struct request *
-deadline_next_request(struct deadline_data *dd, enum dd_data_dir data_dir)
+deadline_next_request(struct deadline_data *dd, enum dd_prio prio,
+		      enum dd_data_dir data_dir)
 {
 	struct request *rq;
 	unsigned long flags;
@@ -276,15 +365,18 @@ deadline_next_request(struct deadline_data *dd, enum dd_data_dir data_dir)
  * deadline_dispatch_requests selects the best request according to
  * read/write expire, fifo_batch, etc
  */
-static struct request *__dd_dispatch_request(struct deadline_data *dd)
+static struct request *__dd_dispatch_request(struct deadline_data *dd,
+					     enum dd_prio prio)
 {
 	struct request *rq, *next_rq;
 	enum dd_data_dir data_dir;
+	u8 ioprio_class;
 
 	lockdep_assert_held(&dd->lock);
 
-	if (!list_empty(&dd->dispatch)) {
-		rq = list_first_entry(&dd->dispatch, struct request, queuelist);
+	if (!list_empty(&dd->dispatch[prio])) {
+		rq = list_first_entry(&dd->dispatch[prio], struct request,
+				      queuelist);
 		list_del_init(&rq->queuelist);
 		goto done;
 	}
@@ -292,9 +384,9 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
 	/*
 	 * batches are currently reads XOR writes
 	 */
-	rq = deadline_next_request(dd, DD_WRITE);
+	rq = deadline_next_request(dd, prio, DD_WRITE);
 	if (!rq)
-		rq = deadline_next_request(dd, DD_READ);
+		rq = deadline_next_request(dd, prio, DD_READ);
 
 	if (rq && dd->batching < dd->fifo_batch)
 		/* we have a next request are still entitled to batch */
@@ -305,10 +397,10 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
 	 * data direction (read / write)
 	 */
 
-	if (!list_empty(&dd->fifo_list[DD_READ])) {
+	if (!list_empty(&dd->fifo_list[prio][DD_READ])) {
 		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[DD_READ]));
 
-		if (deadline_fifo_request(dd, DD_WRITE) &&
+		if (deadline_fifo_request(dd, prio, DD_WRITE) &&
 		    (dd->starved++ >= dd->writes_starved))
 			goto dispatch_writes;
 
@@ -321,7 +413,7 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
 	 * there are either no reads or writes have been starved
 	 */
 
-	if (!list_empty(&dd->fifo_list[DD_WRITE])) {
+	if (!list_empty(&dd->fifo_list[prio][DD_WRITE])) {
 dispatch_writes:
 		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[DD_WRITE]));
 
@@ -338,14 +430,14 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
 	/*
 	 * we are not running a batch, find best request for selected data_dir
 	 */
-	next_rq = deadline_next_request(dd, data_dir);
-	if (deadline_check_fifo(dd, data_dir) || !next_rq) {
+	next_rq = deadline_next_request(dd, prio, data_dir);
+	if (deadline_check_fifo(dd, prio, data_dir) || !next_rq) {
 		/*
 		 * A deadline has expired, the last request was in the other
 		 * direction, or we have run out of higher-sectored requests.
 		 * Start again from the request with the earliest expiry time.
 		 */
-		rq = deadline_fifo_request(dd, data_dir);
+		rq = deadline_fifo_request(dd, prio, data_dir);
 	} else {
 		/*
 		 * The last req was the same dir and we have a next request in
@@ -370,6 +462,13 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
 	dd->batching++;
 	deadline_move_request(dd, rq);
 done:
+	ioprio_class = dd_rq_ioclass(rq);
+	prio = ioprio_class_to_prio[ioprio_class];
+	if (rq->elv.priv[0]) {
+		dd_count(dd, dispatched, prio);
+	} else {
+		WARN_ON_ONCE(true);
+	}
 	/*
 	 * If the request needs its target zone locked, do it.
 	 */
@@ -390,9 +489,14 @@ static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
 {
 	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
 	struct request *rq;
+	enum dd_prio prio;
 
 	spin_lock(&dd->lock);
-	rq = __dd_dispatch_request(dd);
+	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+		rq = __dd_dispatch_request(dd, prio);
+		if (rq)
+			break;
+	}
 	spin_unlock(&dd->lock);
 
 	return rq;
@@ -439,9 +543,14 @@ static int dd_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
 static void dd_exit_sched(struct elevator_queue *e)
 {
 	struct deadline_data *dd = e->elevator_data;
+	enum dd_prio prio;
+
+	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+		WARN_ON_ONCE(!list_empty(&dd->fifo_list[prio][DD_READ]));
+		WARN_ON_ONCE(!list_empty(&dd->fifo_list[prio][DD_WRITE]));
+	}
 
-	BUG_ON(!list_empty(&dd->fifo_list[DD_READ]));
-	BUG_ON(!list_empty(&dd->fifo_list[DD_WRITE]));
+	free_percpu(dd->stats);
 
 	kfree(dd);
 }
@@ -453,20 +562,29 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
 {
 	struct deadline_data *dd;
 	struct elevator_queue *eq;
+	enum dd_prio prio;
+	int ret = -ENOMEM;
 
 	eq = elevator_alloc(q, e);
 	if (!eq)
-		return -ENOMEM;
+		return ret;
 
 	dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
-	if (!dd) {
-		kobject_put(&eq->kobj);
-		return -ENOMEM;
-	}
+	if (!dd)
+		goto put_eq;
+
 	eq->elevator_data = dd;
 
-	INIT_LIST_HEAD(&dd->fifo_list[DD_READ]);
-	INIT_LIST_HEAD(&dd->fifo_list[DD_WRITE]);
+	dd->stats = alloc_percpu_gfp(typeof(*dd->stats),
+				     GFP_KERNEL | __GFP_ZERO);
+	if (!dd->stats)
+		goto free_dd;
+
+	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
+		INIT_LIST_HEAD(&dd->fifo_list[prio][DD_READ]);
+		INIT_LIST_HEAD(&dd->fifo_list[prio][DD_WRITE]);
+		INIT_LIST_HEAD(&dd->dispatch[prio]);
+	}
 	dd->sort_list[DD_READ] = RB_ROOT;
 	dd->sort_list[DD_WRITE] = RB_ROOT;
 	dd->fifo_expire[DD_READ] = read_expire;
@@ -476,10 +594,16 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
 	dd->fifo_batch = fifo_batch;
 	spin_lock_init(&dd->lock);
 	spin_lock_init(&dd->zone_lock);
-	INIT_LIST_HEAD(&dd->dispatch);
 
 	q->elevator = eq;
 	return 0;
+
+free_dd:
+	kfree(dd);
+
+put_eq:
+	kobject_put(&eq->kobj);
+	return ret;
 }
 
 /*
@@ -539,6 +663,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
 	const enum dd_data_dir data_dir = rq_data_dir(rq);
+	u16 ioprio = req_get_ioprio(rq);
+	u8 ioprio_class = IOPRIO_PRIO_CLASS(ioprio);
+	enum dd_prio prio;
 
 	lockdep_assert_held(&dd->lock);
 
@@ -548,13 +675,18 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 	 */
 	blk_req_zone_write_unlock(rq);
 
+	prio = ioprio_class_to_prio[ioprio_class];
+	dd_count(dd, inserted, prio);
+	WARN_ON_ONCE(rq->elv.priv[0]);
+	rq->elv.priv[0] = (void *)1ULL;
+
 	if (blk_mq_sched_try_insert_merge(q, rq))
 		return;
 
 	trace_block_rq_insert(rq);
 
 	if (at_head) {
-		list_add(&rq->queuelist, &dd->dispatch);
+		list_add(&rq->queuelist, &dd->dispatch[prio]);
 	} else {
 		deadline_add_rq_rb(dd, rq);
 
@@ -568,7 +700,7 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		 * set expire time and add to fifo list
 		 */
 		rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
-		list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
+		list_add_tail(&rq->queuelist, &dd->fifo_list[prio][data_dir]);
 	}
 }
 
@@ -592,12 +724,10 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 	spin_unlock(&dd->lock);
 }
 
-/*
- * Nothing to do here. This is defined only to ensure that .finish_request
- * method is called upon request completion.
- */
+/* Callback from inside blk_mq_rq_ctx_init(). */
 static void dd_prepare_request(struct request *rq)
 {
+	rq->elv.priv[0] = NULL;
 }
 
 /*
@@ -619,26 +749,41 @@ static void dd_prepare_request(struct request *rq)
 static void dd_finish_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;
+	struct deadline_data *dd = q->elevator->elevator_data;
+	const u8 ioprio_class = dd_rq_ioclass(rq);
+	const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
+
+	if (rq->elv.priv[0])
+		dd_count(dd, completed, prio);
 
 	if (blk_queue_is_zoned(q)) {
-		struct deadline_data *dd = q->elevator->elevator_data;
 		unsigned long flags;
 
 		spin_lock_irqsave(&dd->zone_lock, flags);
 		blk_req_zone_write_unlock(rq);
-		if (!list_empty(&dd->fifo_list[DD_WRITE]))
+		if (!list_empty(&dd->fifo_list[prio][DD_WRITE]))
 			blk_mq_sched_mark_restart_hctx(rq->mq_hctx);
 		spin_unlock_irqrestore(&dd->zone_lock, flags);
 	}
 }
 
+static bool dd_has_work_for_prio(struct deadline_data *dd, enum dd_prio prio)
+{
+	return !list_empty_careful(&dd->dispatch[prio]) ||
+		!list_empty_careful(&dd->fifo_list[prio][DD_READ]) ||
+		!list_empty_careful(&dd->fifo_list[prio][DD_WRITE]);
+}
+
 static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
 {
 	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
+	enum dd_prio prio;
+
+	for (prio = 0; prio <= DD_PRIO_MAX; prio++)
+		if (dd_has_work_for_prio(dd, prio))
+			return true;
 
-	return !list_empty_careful(&dd->dispatch) ||
-		!list_empty_careful(&dd->fifo_list[0]) ||
-		!list_empty_careful(&dd->fifo_list[1]);
+	return false;
 }
 
 /*
@@ -702,7 +847,7 @@ static struct elv_fs_entry deadline_attrs[] = {
 };
 
 #ifdef CONFIG_BLK_DEBUG_FS
-#define DEADLINE_DEBUGFS_DDIR_ATTRS(ddir, name)				\
+#define DEADLINE_DEBUGFS_DDIR_ATTRS(prio, data_dir, name)		\
 static void *deadline_##name##_fifo_start(struct seq_file *m,		\
 					  loff_t *pos)			\
 	__acquires(&dd->lock)						\
@@ -711,7 +856,7 @@ static void *deadline_##name##_fifo_start(struct seq_file *m,		\
 	struct deadline_data *dd = q->elevator->elevator_data;		\
 									\
 	spin_lock(&dd->lock);						\
-	return seq_list_start(&dd->fifo_list[ddir], *pos);		\
+	return seq_list_start(&dd->fifo_list[prio][data_dir], *pos);	\
 }									\
 									\
 static void *deadline_##name##_fifo_next(struct seq_file *m, void *v,	\
@@ -720,7 +865,7 @@ static void *deadline_##name##_fifo_next(struct seq_file *m, void *v,	\
 	struct request_queue *q = m->private;				\
 	struct deadline_data *dd = q->elevator->elevator_data;		\
 									\
-	return seq_list_next(v, &dd->fifo_list[ddir], pos);		\
+	return seq_list_next(v, &dd->fifo_list[prio][data_dir], pos);	\
 }									\
 									\
 static void deadline_##name##_fifo_stop(struct seq_file *m, void *v)	\
@@ -737,22 +882,31 @@ static const struct seq_operations deadline_##name##_fifo_seq_ops = {	\
 	.next	= deadline_##name##_fifo_next,				\
 	.stop	= deadline_##name##_fifo_stop,				\
 	.show	= blk_mq_debugfs_rq_show,				\
-};									\
-									\
+};
+
+#define DEADLINE_DEBUGFS_NEXT_RQ(data_dir, name)			\
 static int deadline_##name##_next_rq_show(void *data,			\
 					  struct seq_file *m)		\
 {									\
 	struct request_queue *q = data;					\
 	struct deadline_data *dd = q->elevator->elevator_data;		\
-	struct request *rq = dd->next_rq[ddir];				\
+	struct request *rq = dd->next_rq[data_dir];			\
 									\
 	if (rq)								\
 		__blk_mq_debugfs_rq_show(m, rq);			\
 	return 0;							\
 }
-DEADLINE_DEBUGFS_DDIR_ATTRS(DD_READ, read)
-DEADLINE_DEBUGFS_DDIR_ATTRS(DD_WRITE, write)
+
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_READ, read0)
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_WRITE, write0)
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_READ, read1)
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_WRITE, write1)
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_READ, read2)
+DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_WRITE, write2)
+DEADLINE_DEBUGFS_NEXT_RQ(DD_READ, read)
+DEADLINE_DEBUGFS_NEXT_RQ(DD_WRITE, write)
 #undef DEADLINE_DEBUGFS_DDIR_ATTRS
+#undef DEADLINE_DEBUGFS_NEXT_RQ
 
 static int deadline_batching_show(void *data, struct seq_file *m)
 {
@@ -781,50 +935,99 @@ static int dd_async_depth_show(void *data, struct seq_file *m)
 	return 0;
 }
 
-static void *deadline_dispatch_start(struct seq_file *m, loff_t *pos)
-	__acquires(&dd->lock)
+static int dd_queued_show(void *data, struct seq_file *m)
 {
-	struct request_queue *q = m->private;
+	struct request_queue *q = data;
 	struct deadline_data *dd = q->elevator->elevator_data;
 
-	spin_lock(&dd->lock);
-	return seq_list_start(&dd->dispatch, *pos);
+	seq_printf(m, "%u %u %u\n", dd_queued(dd, DD_RT_PRIO),
+		   dd_queued(dd, DD_BE_PRIO),
+		   dd_queued(dd, DD_IDLE_PRIO));
+	return 0;
 }
 
-static void *deadline_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
+/* Number of requests owned by the block driver for a given priority. */
+static u32 dd_owned_by_driver(struct deadline_data *dd, enum dd_prio prio)
 {
-	struct request_queue *q = m->private;
-	struct deadline_data *dd = q->elevator->elevator_data;
-
-	return seq_list_next(v, &dd->dispatch, pos);
+	return dd_sum(dd, dispatched, prio) + dd_sum(dd, merged, prio)
+		- dd_sum(dd, completed, prio);
 }
 
-static void deadline_dispatch_stop(struct seq_file *m, void *v)
-	__releases(&dd->lock)
+static int dd_owned_by_driver_show(void *data, struct seq_file *m)
 {
-	struct request_queue *q = m->private;
+	struct request_queue *q = data;
 	struct deadline_data *dd = q->elevator->elevator_data;
 
-	spin_unlock(&dd->lock);
+	seq_printf(m, "%u %u %u\n", dd_owned_by_driver(dd, DD_RT_PRIO),
+		   dd_owned_by_driver(dd, DD_BE_PRIO),
+		   dd_owned_by_driver(dd, DD_IDLE_PRIO));
+	return 0;
 }
 
-static const struct seq_operations deadline_dispatch_seq_ops = {
-	.start	= deadline_dispatch_start,
-	.next	= deadline_dispatch_next,
-	.stop	= deadline_dispatch_stop,
-	.show	= blk_mq_debugfs_rq_show,
-};
+#define DEADLINE_DISPATCH_ATTR(prio)					\
+static void *deadline_dispatch##prio##_start(struct seq_file *m,	\
+					     loff_t *pos)		\
+	__acquires(&dd->lock)						\
+{									\
+	struct request_queue *q = m->private;				\
+	struct deadline_data *dd = q->elevator->elevator_data;		\
+									\
+	spin_lock(&dd->lock);						\
+	return seq_list_start(&dd->dispatch[prio], *pos);		\
+}									\
+									\
+static void *deadline_dispatch##prio##_next(struct seq_file *m,		\
+					    void *v, loff_t *pos)	\
+{									\
+	struct request_queue *q = m->private;				\
+	struct deadline_data *dd = q->elevator->elevator_data;		\
+									\
+	return seq_list_next(v, &dd->dispatch[prio], pos);		\
+}									\
+									\
+static void deadline_dispatch##prio##_stop(struct seq_file *m, void *v)	\
+	__releases(&dd->lock)						\
+{									\
+	struct request_queue *q = m->private;				\
+	struct deadline_data *dd = q->elevator->elevator_data;		\
+									\
+	spin_unlock(&dd->lock);						\
+}									\
+									\
+static const struct seq_operations deadline_dispatch##prio##_seq_ops = { \
+	.start	= deadline_dispatch##prio##_start,			\
+	.next	= deadline_dispatch##prio##_next,			\
+	.stop	= deadline_dispatch##prio##_stop,			\
+	.show	= blk_mq_debugfs_rq_show,				\
+}
+
+DEADLINE_DISPATCH_ATTR(0);
+DEADLINE_DISPATCH_ATTR(1);
+DEADLINE_DISPATCH_ATTR(2);
+#undef DEADLINE_DISPATCH_ATTR
 
-#define DEADLINE_QUEUE_DDIR_ATTRS(name)						\
-	{#name "_fifo_list", 0400, .seq_ops = &deadline_##name##_fifo_seq_ops},	\
+#define DEADLINE_QUEUE_DDIR_ATTRS(name)					\
+	{#name "_fifo_list", 0400,					\
+			.seq_ops = &deadline_##name##_fifo_seq_ops}
+#define DEADLINE_NEXT_RQ_ATTR(name)					\
 	{#name "_next_rq", 0400, deadline_##name##_next_rq_show}
 static const struct blk_mq_debugfs_attr deadline_queue_debugfs_attrs[] = {
-	DEADLINE_QUEUE_DDIR_ATTRS(read),
-	DEADLINE_QUEUE_DDIR_ATTRS(write),
+	DEADLINE_QUEUE_DDIR_ATTRS(read0),
+	DEADLINE_QUEUE_DDIR_ATTRS(write0),
+	DEADLINE_QUEUE_DDIR_ATTRS(read1),
+	DEADLINE_QUEUE_DDIR_ATTRS(write1),
+	DEADLINE_QUEUE_DDIR_ATTRS(read2),
+	DEADLINE_QUEUE_DDIR_ATTRS(write2),
+	DEADLINE_NEXT_RQ_ATTR(read),
+	DEADLINE_NEXT_RQ_ATTR(write),
 	{"batching", 0400, deadline_batching_show},
 	{"starved", 0400, deadline_starved_show},
 	{"async_depth", 0400, dd_async_depth_show},
-	{"dispatch", 0400, .seq_ops = &deadline_dispatch_seq_ops},
+	{"dispatch0", 0400, .seq_ops = &deadline_dispatch0_seq_ops},
+	{"dispatch1", 0400, .seq_ops = &deadline_dispatch1_seq_ops},
+	{"dispatch2", 0400, .seq_ops = &deadline_dispatch2_seq_ops},
+	{"owned_by_driver", 0400, dd_owned_by_driver_show},
+	{"queued", 0400, dd_queued_show},
 	{},
 };
 #undef DEADLINE_QUEUE_DDIR_ATTRS
@@ -874,6 +1077,6 @@ static void __exit deadline_exit(void)
 module_init(deadline_init);
 module_exit(deadline_exit);
 
-MODULE_AUTHOR("Jens Axboe");
+MODULE_AUTHOR("Jens Axboe, Damien Le Moal and Bart Van Assche");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MQ deadline IO scheduler");

  parent reply	other threads:[~2021-06-08 23:07 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 23:06 [PATCH 00/14] Improve " Bart Van Assche
2021-06-08 23:06 ` [PATCH 01/14] block/Kconfig: Make the BLK_WBT and BLK_WBT_MQ entries consecutive Bart Van Assche
2021-06-09  4:14   ` Damien Le Moal
2021-06-09  7:03   ` Johannes Thumshirn
2021-06-10  6:02   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 02/14] block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls Bart Van Assche
2021-06-09  4:19   ` Damien Le Moal
2021-06-09  7:05   ` Johannes Thumshirn
2021-06-10  6:02   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 03/14] block/blk-rq-qos: Move a function from a header file into a C file Bart Van Assche
2021-06-09  4:22   ` Damien Le Moal
2021-06-10  6:03   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 04/14] block: Introduce the ioprio rq-qos policy Bart Van Assche
2021-06-09  4:40   ` Damien Le Moal
2021-06-09 16:48     ` Bart Van Assche
2021-06-10  0:29       ` Damien Le Moal
2021-06-10  6:20   ` Hannes Reinecke
2021-06-10 17:14     ` Bart Van Assche
2021-06-08 23:06 ` [PATCH 05/14] block/mq-deadline: Add several comments Bart Van Assche
2021-06-10  6:21   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 06/14] block/mq-deadline: Add two lockdep_assert_held() statements Bart Van Assche
2021-06-10  6:21   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 07/14] block/mq-deadline: Remove two local variables Bart Van Assche
2021-06-10  6:22   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 08/14] block/mq-deadline: Rename dd_init_queue() and dd_exit_queue() Bart Van Assche
2021-06-08 23:06 ` [PATCH 09/14] block/mq-deadline: Improve compile-time argument checking Bart Van Assche
2021-06-08 23:06 ` [PATCH 10/14] block/mq-deadline: Improve the sysfs show and store macros Bart Van Assche
2021-06-09  4:46   ` Damien Le Moal
2021-06-09 16:54     ` Bart Van Assche
2021-06-10  0:31       ` Damien Le Moal
2021-06-09  7:11   ` Johannes Thumshirn
2021-06-09 16:59     ` Bart Van Assche
2021-06-10  6:23   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 11/14] block/mq-deadline: Reserve 25% of scheduler tags for synchronous requests Bart Van Assche
2021-06-10  6:26   ` Hannes Reinecke
2021-06-08 23:07 ` Bart Van Assche [this message]
2021-06-09  5:03   ` [PATCH 12/14] block/mq-deadline: Add I/O priority support Damien Le Moal
2021-06-09 17:25     ` Bart Van Assche
2021-06-10  0:39       ` Damien Le Moal
2021-06-10  6:35   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 13/14] block/mq-deadline: Add cgroup support Bart Van Assche
2021-06-10  6:37   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 14/14] block/mq-deadline: Prioritize high-priority requests Bart Van Assche
2021-06-09  5:10   ` Damien Le Moal
2021-06-10  6:43   ` Hannes Reinecke

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