diff mbox series

[v13,1/9] block: Introduce queue limits for copy-offload support

Message ID 20230627183629.26571-2-nj.shetty@samsung.com (mailing list archive)
State New, archived
Headers show
Series [v13,1/9] block: Introduce queue limits for copy-offload support | expand

Commit Message

Nitesh Shetty June 27, 2023, 6:36 p.m. UTC
Add device limits as sysfs entries,
        - copy_offload (RW)
        - copy_max_bytes (RW)
        - copy_max_bytes_hw (RO)

Above limits help to split the copy payload in block layer.
copy_offload: used for setting copy offload(1) or emulation(0).
copy_max_bytes: maximum total length of copy in single payload.
copy_max_bytes_hw: Reflects the device supported maximum limit.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
---
 Documentation/ABI/stable/sysfs-block | 33 +++++++++++++++
 block/blk-settings.c                 | 24 +++++++++++
 block/blk-sysfs.c                    | 63 ++++++++++++++++++++++++++++
 include/linux/blkdev.h               | 12 ++++++
 include/uapi/linux/fs.h              |  3 ++
 5 files changed, 135 insertions(+)

Comments

Nitesh Shetty June 28, 2023, 3:35 p.m. UTC | #1
On 23/06/28 03:40PM, Damien Le Moal wrote:
>On 6/28/23 03:36, Nitesh Shetty wrote:
>> Add device limits as sysfs entries,
>>         - copy_offload (RW)
>>         - copy_max_bytes (RW)
>>         - copy_max_bytes_hw (RO)
>>
>> Above limits help to split the copy payload in block layer.
>> copy_offload: used for setting copy offload(1) or emulation(0).
>> copy_max_bytes: maximum total length of copy in single payload.
>> copy_max_bytes_hw: Reflects the device supported maximum limit.
>>
>> Reviewed-by: Hannes Reinecke <hare@suse.de>
>> Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
>> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
>> Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
>> ---
>>  Documentation/ABI/stable/sysfs-block | 33 +++++++++++++++
>>  block/blk-settings.c                 | 24 +++++++++++
>>  block/blk-sysfs.c                    | 63 ++++++++++++++++++++++++++++
>>  include/linux/blkdev.h               | 12 ++++++
>>  include/uapi/linux/fs.h              |  3 ++
>>  5 files changed, 135 insertions(+)
>>
>> diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
>> index c57e5b7cb532..3c97303f658b 100644
>> --- a/Documentation/ABI/stable/sysfs-block
>> +++ b/Documentation/ABI/stable/sysfs-block
>> @@ -155,6 +155,39 @@ Description:
>>  		last zone of the device which may be smaller.
>>
>>
>> +What:		/sys/block/<disk>/queue/copy_offload
>> +Date:		June 2023
>> +Contact:	linux-block@vger.kernel.org
>> +Description:
>> +		[RW] When read, this file shows whether offloading copy to a
>> +		device is enabled (1) or disabled (0). Writing '0' to this
>> +		file will disable offloading copies for this device.
>> +		Writing any '1' value will enable this feature. If the device
>> +		does not support offloading, then writing 1, will result in an
>> +		error.
>
>I am still not convinced that this one is really necessary. copy_max_bytes_hw !=
>0 indicates that the devices supports copy offload. And setting copy_max_bytes
>to 0 can be used to disable copy offload (which probably should be the default
>for now).
>

Agreed, we will do this in next iteration.

>> +
>> +
>> +What:		/sys/block/<disk>/queue/copy_max_bytes
>> +Date:		June 2023
>> +Contact:	linux-block@vger.kernel.org
>> +Description:
>> +		[RW] This is the maximum number of bytes that the block layer
>> +		will allow for a copy request. This will is always smaller or
>
>will is -> is
>

acked

>> +		equal to the maximum size allowed by the hardware, indicated by
>> +		'copy_max_bytes_hw'. An attempt to set a value higher than
>> +		'copy_max_bytes_hw' will truncate this to 'copy_max_bytes_hw'.
>> +
>> +
>> +What:		/sys/block/<disk>/queue/copy_max_bytes_hw
>
>Nit: In keeping with the spirit of attributes like
>max_hw_sectors_kb/max_sectors_kb, I would call this one copy_max_hw_bytes.
>

acked, will update in next iteration.

>> +Date:		June 2023
>> +Contact:	linux-block@vger.kernel.org
>> +Description:
>> +		[RO] This is the maximum number of bytes that the hardware
>> +		will allow for single data copy request.
>> +		A value of 0 means that the device does not support
>> +		copy offload.
>> +
>> +
>>  What:		/sys/block/<disk>/queue/crypto/
>>  Date:		February 2022
>>  Contact:	linux-block@vger.kernel.org
>> diff --git a/block/blk-settings.c b/block/blk-settings.c
>> index 4dd59059b788..738cd3f21259 100644
>> --- a/block/blk-settings.c
>> +++ b/block/blk-settings.c
>> @@ -59,6 +59,8 @@ void blk_set_default_limits(struct queue_limits *lim)
>>  	lim->zoned = BLK_ZONED_NONE;
>>  	lim->zone_write_granularity = 0;
>>  	lim->dma_alignment = 511;
>> +	lim->max_copy_sectors_hw = 0;
>> +	lim->max_copy_sectors = 0;
>>  }
>>
>>  /**
>> @@ -82,6 +84,8 @@ void blk_set_stacking_limits(struct queue_limits *lim)
>>  	lim->max_dev_sectors = UINT_MAX;
>>  	lim->max_write_zeroes_sectors = UINT_MAX;
>>  	lim->max_zone_append_sectors = UINT_MAX;
>> +	lim->max_copy_sectors_hw = UINT_MAX;
>> +	lim->max_copy_sectors = UINT_MAX;
>>  }
>>  EXPORT_SYMBOL(blk_set_stacking_limits);
>>
>> @@ -183,6 +187,22 @@ void blk_queue_max_discard_sectors(struct request_queue *q,
>>  }
>>  EXPORT_SYMBOL(blk_queue_max_discard_sectors);
>>
>> +/**
>> + * blk_queue_max_copy_sectors_hw - set max sectors for a single copy payload
>> + * @q:  the request queue for the device
>> + * @max_copy_sectors: maximum number of sectors to copy
>> + **/
>> +void blk_queue_max_copy_sectors_hw(struct request_queue *q,
>> +		unsigned int max_copy_sectors)
>> +{
>> +	if (max_copy_sectors > (COPY_MAX_BYTES >> SECTOR_SHIFT))
>> +		max_copy_sectors = COPY_MAX_BYTES >> SECTOR_SHIFT;
>> +
>> +	q->limits.max_copy_sectors_hw = max_copy_sectors;
>> +	q->limits.max_copy_sectors = max_copy_sectors;
>> +}
>> +EXPORT_SYMBOL_GPL(blk_queue_max_copy_sectors_hw);
>> +
>>  /**
>>   * blk_queue_max_secure_erase_sectors - set max sectors for a secure erase
>>   * @q:  the request queue for the device
>> @@ -578,6 +598,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
>>  	t->max_segment_size = min_not_zero(t->max_segment_size,
>>  					   b->max_segment_size);
>>
>> +	t->max_copy_sectors = min(t->max_copy_sectors, b->max_copy_sectors);
>> +	t->max_copy_sectors_hw = min(t->max_copy_sectors_hw,
>> +						b->max_copy_sectors_hw);
>> +
>>  	t->misaligned |= b->misaligned;
>>
>>  	alignment = queue_limit_alignment_offset(b, start);
>> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
>> index afc797fb0dfc..43551778d035 100644
>> --- a/block/blk-sysfs.c
>> +++ b/block/blk-sysfs.c
>> @@ -199,6 +199,62 @@ static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *pag
>>  	return queue_var_show(0, page);
>>  }
>>
>> +static ssize_t queue_copy_offload_show(struct request_queue *q, char *page)
>> +{
>> +	return queue_var_show(blk_queue_copy(q), page);
>> +}
>> +
>> +static ssize_t queue_copy_offload_store(struct request_queue *q,
>> +				       const char *page, size_t count)
>> +{
>> +	unsigned long copy_offload;
>> +	ssize_t ret = queue_var_store(&copy_offload, page, count);
>> +
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (copy_offload && !q->limits.max_copy_sectors_hw)
>> +		return -EINVAL;
>> +
>> +	if (copy_offload)
>> +		blk_queue_flag_set(QUEUE_FLAG_COPY, q);
>> +	else
>> +		blk_queue_flag_clear(QUEUE_FLAG_COPY, q);
>> +
>> +	return count;
>> +}
>
>See above. I think we can drop this attribute.
>
acked

Thank you, 
Nitesh Shetty
Christoph Hellwig July 20, 2023, 7:06 a.m. UTC | #2
Just a little heads up:  I think we need to properly solve the
hw vs user limit as the various ad-hoc mechanisms tend to be
broken and don't scale.  I plan to start looking into that the
next days.

On Wed, Jun 28, 2023 at 12:06:15AM +0530, Nitesh Shetty wrote:
> Add device limits as sysfs entries,
>         - copy_offload (RW)
>         - copy_max_bytes (RW)
>         - copy_max_bytes_hw (RO)
> 
> Above limits help to split the copy payload in block layer.
> copy_offload: used for setting copy offload(1) or emulation(0).
> copy_max_bytes: maximum total length of copy in single payload.
> copy_max_bytes_hw: Reflects the device supported maximum limit.

Why do we need the separate copy_offload boolean vs just looking
at the max_bytes value?
Christoph Hellwig July 20, 2023, 7:58 a.m. UTC | #3
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index b7b56871029c..dff56813f95a 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -64,6 +64,9 @@ struct fstrim_range {
>  	__u64 minlen;
>  };
>  
> +/* maximum copy offload length, this is set to 128MB based on current testing */
> +#define COPY_MAX_BYTES	(1 << 27)

This should not be in the UAPI.  It is a totally arbitrary internal
limit.
diff mbox series

Patch

diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index c57e5b7cb532..3c97303f658b 100644
--- a/Documentation/ABI/stable/sysfs-block
+++ b/Documentation/ABI/stable/sysfs-block
@@ -155,6 +155,39 @@  Description:
 		last zone of the device which may be smaller.
 
 
+What:		/sys/block/<disk>/queue/copy_offload
+Date:		June 2023
+Contact:	linux-block@vger.kernel.org
+Description:
+		[RW] When read, this file shows whether offloading copy to a
+		device is enabled (1) or disabled (0). Writing '0' to this
+		file will disable offloading copies for this device.
+		Writing any '1' value will enable this feature. If the device
+		does not support offloading, then writing 1, will result in an
+		error.
+
+
+What:		/sys/block/<disk>/queue/copy_max_bytes
+Date:		June 2023
+Contact:	linux-block@vger.kernel.org
+Description:
+		[RW] This is the maximum number of bytes that the block layer
+		will allow for a copy request. This will is always smaller or
+		equal to the maximum size allowed by the hardware, indicated by
+		'copy_max_bytes_hw'. An attempt to set a value higher than
+		'copy_max_bytes_hw' will truncate this to 'copy_max_bytes_hw'.
+
+
+What:		/sys/block/<disk>/queue/copy_max_bytes_hw
+Date:		June 2023
+Contact:	linux-block@vger.kernel.org
+Description:
+		[RO] This is the maximum number of bytes that the hardware
+		will allow for single data copy request.
+		A value of 0 means that the device does not support
+		copy offload.
+
+
 What:		/sys/block/<disk>/queue/crypto/
 Date:		February 2022
 Contact:	linux-block@vger.kernel.org
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 4dd59059b788..738cd3f21259 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -59,6 +59,8 @@  void blk_set_default_limits(struct queue_limits *lim)
 	lim->zoned = BLK_ZONED_NONE;
 	lim->zone_write_granularity = 0;
 	lim->dma_alignment = 511;
+	lim->max_copy_sectors_hw = 0;
+	lim->max_copy_sectors = 0;
 }
 
 /**
@@ -82,6 +84,8 @@  void blk_set_stacking_limits(struct queue_limits *lim)
 	lim->max_dev_sectors = UINT_MAX;
 	lim->max_write_zeroes_sectors = UINT_MAX;
 	lim->max_zone_append_sectors = UINT_MAX;
+	lim->max_copy_sectors_hw = UINT_MAX;
+	lim->max_copy_sectors = UINT_MAX;
 }
 EXPORT_SYMBOL(blk_set_stacking_limits);
 
@@ -183,6 +187,22 @@  void blk_queue_max_discard_sectors(struct request_queue *q,
 }
 EXPORT_SYMBOL(blk_queue_max_discard_sectors);
 
+/**
+ * blk_queue_max_copy_sectors_hw - set max sectors for a single copy payload
+ * @q:  the request queue for the device
+ * @max_copy_sectors: maximum number of sectors to copy
+ **/
+void blk_queue_max_copy_sectors_hw(struct request_queue *q,
+		unsigned int max_copy_sectors)
+{
+	if (max_copy_sectors > (COPY_MAX_BYTES >> SECTOR_SHIFT))
+		max_copy_sectors = COPY_MAX_BYTES >> SECTOR_SHIFT;
+
+	q->limits.max_copy_sectors_hw = max_copy_sectors;
+	q->limits.max_copy_sectors = max_copy_sectors;
+}
+EXPORT_SYMBOL_GPL(blk_queue_max_copy_sectors_hw);
+
 /**
  * blk_queue_max_secure_erase_sectors - set max sectors for a secure erase
  * @q:  the request queue for the device
@@ -578,6 +598,10 @@  int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	t->max_segment_size = min_not_zero(t->max_segment_size,
 					   b->max_segment_size);
 
+	t->max_copy_sectors = min(t->max_copy_sectors, b->max_copy_sectors);
+	t->max_copy_sectors_hw = min(t->max_copy_sectors_hw,
+						b->max_copy_sectors_hw);
+
 	t->misaligned |= b->misaligned;
 
 	alignment = queue_limit_alignment_offset(b, start);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index afc797fb0dfc..43551778d035 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -199,6 +199,62 @@  static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *pag
 	return queue_var_show(0, page);
 }
 
+static ssize_t queue_copy_offload_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(blk_queue_copy(q), page);
+}
+
+static ssize_t queue_copy_offload_store(struct request_queue *q,
+				       const char *page, size_t count)
+{
+	unsigned long copy_offload;
+	ssize_t ret = queue_var_store(&copy_offload, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	if (copy_offload && !q->limits.max_copy_sectors_hw)
+		return -EINVAL;
+
+	if (copy_offload)
+		blk_queue_flag_set(QUEUE_FLAG_COPY, q);
+	else
+		blk_queue_flag_clear(QUEUE_FLAG_COPY, q);
+
+	return count;
+}
+
+static ssize_t queue_copy_max_hw_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%llu\n", (unsigned long long)
+			q->limits.max_copy_sectors_hw << SECTOR_SHIFT);
+}
+
+static ssize_t queue_copy_max_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%llu\n", (unsigned long long)
+			q->limits.max_copy_sectors << SECTOR_SHIFT);
+}
+
+static ssize_t queue_copy_max_store(struct request_queue *q,
+				       const char *page, size_t count)
+{
+	unsigned long max_copy;
+	ssize_t ret = queue_var_store(&max_copy, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	if (max_copy & (queue_logical_block_size(q) - 1))
+		return -EINVAL;
+
+	max_copy >>= SECTOR_SHIFT;
+	q->limits.max_copy_sectors = min_t(unsigned int, max_copy,
+					q->limits.max_copy_sectors_hw);
+
+	return count;
+}
+
 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 {
 	return queue_var_show(0, page);
@@ -522,6 +578,10 @@  QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 
+QUEUE_RW_ENTRY(queue_copy_offload, "copy_offload");
+QUEUE_RO_ENTRY(queue_copy_max_hw, "copy_max_bytes_hw");
+QUEUE_RW_ENTRY(queue_copy_max, "copy_max_bytes");
+
 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 QUEUE_RW_ENTRY(queue_poll, "io_poll");
@@ -638,6 +698,9 @@  static struct attribute *queue_attrs[] = {
 	&queue_discard_max_entry.attr,
 	&queue_discard_max_hw_entry.attr,
 	&queue_discard_zeroes_data_entry.attr,
+	&queue_copy_offload_entry.attr,
+	&queue_copy_max_hw_entry.attr,
+	&queue_copy_max_entry.attr,
 	&queue_write_same_max_entry.attr,
 	&queue_write_zeroes_max_entry.attr,
 	&queue_zone_append_max_entry.attr,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ed44a997f629..6098665953e6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -309,6 +309,9 @@  struct queue_limits {
 	unsigned int		discard_alignment;
 	unsigned int		zone_write_granularity;
 
+	unsigned int		max_copy_sectors_hw;
+	unsigned int		max_copy_sectors;
+
 	unsigned short		max_segments;
 	unsigned short		max_integrity_segments;
 	unsigned short		max_discard_segments;
@@ -554,6 +557,7 @@  struct request_queue {
 #define QUEUE_FLAG_NOWAIT       29	/* device supports NOWAIT */
 #define QUEUE_FLAG_SQ_SCHED     30	/* single queue style io dispatch */
 #define QUEUE_FLAG_SKIP_TAGSET_QUIESCE	31 /* quiesce_tagset skip the queue*/
+#define QUEUE_FLAG_COPY		32	/* enable/disable device copy offload */
 
 #define QUEUE_FLAG_MQ_DEFAULT	((1UL << QUEUE_FLAG_IO_STAT) |		\
 				 (1UL << QUEUE_FLAG_SAME_COMP) |	\
@@ -574,6 +578,7 @@  bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 	test_bit(QUEUE_FLAG_STABLE_WRITES, &(q)->queue_flags)
 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
+#define blk_queue_copy(q)	test_bit(QUEUE_FLAG_COPY, &(q)->queue_flags)
 #define blk_queue_zone_resetall(q)	\
 	test_bit(QUEUE_FLAG_ZONE_RESETALL, &(q)->queue_flags)
 #define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
@@ -891,6 +896,8 @@  extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 extern void blk_queue_max_discard_segments(struct request_queue *,
 		unsigned short);
+extern void blk_queue_max_copy_sectors_hw(struct request_queue *q,
+		unsigned int max_copy_sectors);
 void blk_queue_max_secure_erase_sectors(struct request_queue *q,
 		unsigned int max_sectors);
 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
@@ -1210,6 +1217,11 @@  static inline unsigned int bdev_discard_granularity(struct block_device *bdev)
 	return bdev_get_queue(bdev)->limits.discard_granularity;
 }
 
+static inline unsigned int bdev_max_copy_sectors(struct block_device *bdev)
+{
+	return bdev_get_queue(bdev)->limits.max_copy_sectors;
+}
+
 static inline unsigned int
 bdev_max_secure_erase_sectors(struct block_device *bdev)
 {
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index b7b56871029c..dff56813f95a 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -64,6 +64,9 @@  struct fstrim_range {
 	__u64 minlen;
 };
 
+/* maximum copy offload length, this is set to 128MB based on current testing */
+#define COPY_MAX_BYTES	(1 << 27)
+
 /* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
 #define FILE_DEDUPE_RANGE_SAME		0
 #define FILE_DEDUPE_RANGE_DIFFERS	1