diff mbox series

[V9,6/8] block, bfq: retrieve independent access ranges from request queue

Message ID 20221208104351.35038-7-paolo.valente@linaro.org (mailing list archive)
State New, archived
Headers show
Series block, bfq: extend bfq to support multi-actuator drives | expand

Commit Message

Paolo Valente Dec. 8, 2022, 10:43 a.m. UTC 
From: Federico Gavioli <f.gavioli97@gmail.com>

This patch implements the code to gather the content of the
independent_access_ranges structure from the request_queue and copy
it into the queue's bfq_data. This copy is done at queue initialization.

We copy the access ranges into the bfq_data to avoid taking the queue
lock each time we access the ranges.

This implementation, however, puts a limit to the maximum independent
ranges supported by the scheduler. Such a limit is equal to the constant
BFQ_MAX_ACTUATORS. This limit was placed to avoid the allocation of
dynamic memory.

Co-developed-by: Rory Chen <rory.c.chen@seagate.com>
Signed-off-by: Rory Chen <rory.c.chen@seagate.com>
Signed-off-by: Federico Gavioli <f.gavioli97@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
---
 block/bfq-iosched.c | 60 +++++++++++++++++++++++++++++++++++++++------
 block/bfq-iosched.h |  8 +++++-
 2 files changed, 59 insertions(+), 9 deletions(-)

Comments

Damien Le Moal Dec. 9, 2022, 1:39 a.m. UTC | #1 
On 12/8/22 19:43, Paolo Valente wrote:
> From: Federico Gavioli <f.gavioli97@gmail.com>
> 
> This patch implements the code to gather the content of the
> independent_access_ranges structure from the request_queue and copy
> it into the queue's bfq_data. This copy is done at queue initialization.
> 
> We copy the access ranges into the bfq_data to avoid taking the queue
> lock each time we access the ranges.
> 
> This implementation, however, puts a limit to the maximum independent
> ranges supported by the scheduler. Such a limit is equal to the constant
> BFQ_MAX_ACTUATORS. This limit was placed to avoid the allocation of
> dynamic memory.
> 
> Co-developed-by: Rory Chen <rory.c.chen@seagate.com>
> Signed-off-by: Rory Chen <rory.c.chen@seagate.com>
> Signed-off-by: Federico Gavioli <f.gavioli97@gmail.com>
> Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
> ---
>  block/bfq-iosched.c | 60 +++++++++++++++++++++++++++++++++++++++------
>  block/bfq-iosched.h |  8 +++++-
>  2 files changed, 59 insertions(+), 9 deletions(-)
> 
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index dcecba3c6e23..957ce61faaf2 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -1839,10 +1839,25 @@ static bool bfq_bfqq_higher_class_or_weight(struct bfq_queue *bfqq,
>   */
>  static unsigned int bfq_actuator_index(struct bfq_data *bfqd, struct bio *bio)
>  {
> -	/*
> -	 * Multi-actuator support not complete yet, so always return 0
> -	 * for the moment (to keep incomplete mechanisms off).
> -	 */
> +	unsigned int i;
> +	sector_t end;
> +
> +	/* no search needed if one or zero ranges present */
> +	if (bfqd->num_actuators == 1)
> +		return 0;
> +
> +	/* bio_end_sector(bio) gives the sector after the last one */
> +	end = bio_end_sector(bio) - 1;
> +
> +	for (i = 0; i < bfqd->num_actuators; i++) {
> +		if (end >= bfqd->sector[i] &&
> +		    end < bfqd->sector[i] + bfqd->nr_sectors[i])
> +			return i;
> +	}
> +
> +	WARN_ONCE(true,
> +		  "bfq_actuator_index: bio sector out of ranges: end=%llu\n",
> +		  end);
>  	return 0;
>  }
>  
> @@ -7160,6 +7175,8 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
>  {
>  	struct bfq_data *bfqd;
>  	struct elevator_queue *eq;
> +	unsigned int i;
> +	struct blk_independent_access_ranges *ia_ranges = q->disk->ia_ranges;
>  
>  	eq = elevator_alloc(q, e);
>  	if (!eq)
> @@ -7202,12 +7219,39 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
>  
>  	bfqd->queue = q;
>  
> +	bfqd->num_actuators = 1;
>  	/*
> -	 * Multi-actuator support not complete yet, unconditionally
> -	 * set to only one actuator for the moment (to keep incomplete
> -	 * mechanisms off).
> +	 * If the disk supports multiple actuators, copy independent
> +	 * access ranges from the request queue structure.
>  	 */
> -	bfqd->num_actuators = 1;
> +	spin_lock_irq(&q->queue_lock);
> +	if (ia_ranges) {
> +		/*
> +		 * Check if the disk ia_ranges size exceeds the current bfq
> +		 * actuator limit.
> +		 */
> +		if (ia_ranges->nr_ia_ranges > BFQ_MAX_ACTUATORS) {
> +			pr_crit("nr_ia_ranges higher than act limit: iars=%d, max=%d.\n",
> +				ia_ranges->nr_ia_ranges, BFQ_MAX_ACTUATORS);
> +			pr_crit("Falling back to single actuator mode.\n");
> +		} else {
> +			bfqd->num_actuators = ia_ranges->nr_ia_ranges;
> +
> +			for (i = 0; i < bfqd->num_actuators; i++) {
> +				bfqd->sector[i] = ia_ranges->ia_range[i].sector;
> +				bfqd->nr_sectors[i] =
> +					ia_ranges->ia_range[i].nr_sectors;
> +			}
> +		}
> +	}
> +
> +	/* Otherwise use single-actuator dev info */
> +	if (bfqd->num_actuators == 1) {
> +		bfqd->sector[0] = 0;
> +		bfqd->nr_sectors[0] =
> +			bdev_nr_sectors(dev_to_bdev(disk_to_dev(q->disk)));

get_capacity(q->disk) would be simpler.

> +	}
> +	spin_unlock_irq(&q->queue_lock);
>  
>  	INIT_LIST_HEAD(&bfqd->dispatch);
>  
> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
> index 1450990dba32..953980de6b4b 100644
> --- a/block/bfq-iosched.h
> +++ b/block/bfq-iosched.h
> @@ -810,7 +810,13 @@ struct bfq_data {
>  	 * case of single-actuator drives.
>  	 */
>  	unsigned int num_actuators;
> -
> +	/*
> +	 * Disk independent access ranges for each actuator
> +	 * in this device.
> +	 */
> +	sector_t sector[BFQ_MAX_ACTUATORS];
> +	sector_t nr_sectors[BFQ_MAX_ACTUATORS];
> +	struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
>  };
>  
>  enum bfqq_state_flags {

With the nit above fixed,

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
diff mbox series

Patch

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index dcecba3c6e23..957ce61faaf2 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1839,10 +1839,25 @@  static bool bfq_bfqq_higher_class_or_weight(struct bfq_queue *bfqq,
  */
 static unsigned int bfq_actuator_index(struct bfq_data *bfqd, struct bio *bio)
 {
-	/*
-	 * Multi-actuator support not complete yet, so always return 0
-	 * for the moment (to keep incomplete mechanisms off).
-	 */
+	unsigned int i;
+	sector_t end;
+
+	/* no search needed if one or zero ranges present */
+	if (bfqd->num_actuators == 1)
+		return 0;
+
+	/* bio_end_sector(bio) gives the sector after the last one */
+	end = bio_end_sector(bio) - 1;
+
+	for (i = 0; i < bfqd->num_actuators; i++) {
+		if (end >= bfqd->sector[i] &&
+		    end < bfqd->sector[i] + bfqd->nr_sectors[i])
+			return i;
+	}
+
+	WARN_ONCE(true,
+		  "bfq_actuator_index: bio sector out of ranges: end=%llu\n",
+		  end);
 	return 0;
 }
 
@@ -7160,6 +7175,8 @@  static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
 {
 	struct bfq_data *bfqd;
 	struct elevator_queue *eq;
+	unsigned int i;
+	struct blk_independent_access_ranges *ia_ranges = q->disk->ia_ranges;
 
 	eq = elevator_alloc(q, e);
 	if (!eq)
@@ -7202,12 +7219,39 @@  static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
 
 	bfqd->queue = q;
 
+	bfqd->num_actuators = 1;
 	/*
-	 * Multi-actuator support not complete yet, unconditionally
-	 * set to only one actuator for the moment (to keep incomplete
-	 * mechanisms off).
+	 * If the disk supports multiple actuators, copy independent
+	 * access ranges from the request queue structure.
 	 */
-	bfqd->num_actuators = 1;
+	spin_lock_irq(&q->queue_lock);
+	if (ia_ranges) {
+		/*
+		 * Check if the disk ia_ranges size exceeds the current bfq
+		 * actuator limit.
+		 */
+		if (ia_ranges->nr_ia_ranges > BFQ_MAX_ACTUATORS) {
+			pr_crit("nr_ia_ranges higher than act limit: iars=%d, max=%d.\n",
+				ia_ranges->nr_ia_ranges, BFQ_MAX_ACTUATORS);
+			pr_crit("Falling back to single actuator mode.\n");
+		} else {
+			bfqd->num_actuators = ia_ranges->nr_ia_ranges;
+
+			for (i = 0; i < bfqd->num_actuators; i++) {
+				bfqd->sector[i] = ia_ranges->ia_range[i].sector;
+				bfqd->nr_sectors[i] =
+					ia_ranges->ia_range[i].nr_sectors;
+			}
+		}
+	}
+
+	/* Otherwise use single-actuator dev info */
+	if (bfqd->num_actuators == 1) {
+		bfqd->sector[0] = 0;
+		bfqd->nr_sectors[0] =
+			bdev_nr_sectors(dev_to_bdev(disk_to_dev(q->disk)));
+	}
+	spin_unlock_irq(&q->queue_lock);
 
 	INIT_LIST_HEAD(&bfqd->dispatch);
 
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 1450990dba32..953980de6b4b 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -810,7 +810,13 @@  struct bfq_data {
 	 * case of single-actuator drives.
 	 */
 	unsigned int num_actuators;
-
+	/*
+	 * Disk independent access ranges for each actuator
+	 * in this device.
+	 */
+	sector_t sector[BFQ_MAX_ACTUATORS];
+	sector_t nr_sectors[BFQ_MAX_ACTUATORS];
+	struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
 };
 
 enum bfqq_state_flags {