Commit c23acfac authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: introduce a write_stream_granularity queue limit 



Export the granularity that write streams should be discarded with,
as it is essential for making good use of them.

Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarNitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20250506121732.8211-5-joshi.k@samsung.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d2f526ba

Documentation/ABI/stable/sysfs-block

+8 −0
Original line number Diff line number Diff line
@@ -555,6 +555,14 @@ Description: 
		supported. If supported, valid values are 1 through

		max_write_streams, inclusive.



What:		/sys/block/<disk>/queue/write_stream_granularity

Date:		November 2024

Contact:	linux-block@vger.kernel.org

Description:

		[RO] Granularity of a write stream in bytes.  The granularity

		of a write stream is the size that should be discarded or

		overwritten together to avoid write amplification in the device.



What:		/sys/block/<disk>/queue/max_segments

Date:		March 2010

Contact:	linux-block@vger.kernel.org

block/blk-sysfs.c

+3 −0
Original line number Diff line number Diff line
@@ -135,6 +135,7 @@ QUEUE_SYSFS_LIMIT_SHOW(max_discard_segments) 
QUEUE_SYSFS_LIMIT_SHOW(max_integrity_segments)

QUEUE_SYSFS_LIMIT_SHOW(max_segment_size)

QUEUE_SYSFS_LIMIT_SHOW(max_write_streams)

QUEUE_SYSFS_LIMIT_SHOW(write_stream_granularity)

QUEUE_SYSFS_LIMIT_SHOW(logical_block_size)

QUEUE_SYSFS_LIMIT_SHOW(physical_block_size)

QUEUE_SYSFS_LIMIT_SHOW(chunk_sectors)
@@ -490,6 +491,7 @@ QUEUE_LIM_RO_ENTRY(queue_max_segments, "max_segments"); 
QUEUE_LIM_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");

QUEUE_LIM_RO_ENTRY(queue_max_segment_size, "max_segment_size");

QUEUE_LIM_RO_ENTRY(queue_max_write_streams, "max_write_streams");

QUEUE_LIM_RO_ENTRY(queue_write_stream_granularity, "write_stream_granularity");

QUEUE_RW_ENTRY(elv_iosched, "scheduler");



QUEUE_LIM_RO_ENTRY(queue_logical_block_size, "logical_block_size");
@@ -645,6 +647,7 @@ static struct attribute *queue_attrs[] = { 
	&queue_max_integrity_segments_entry.attr,

	&queue_max_segment_size_entry.attr,

	&queue_max_write_streams_entry.attr,

	&queue_write_stream_granularity_entry.attr,

	&queue_hw_sector_size_entry.attr,

	&queue_logical_block_size_entry.attr,

	&queue_physical_block_size_entry.attr,

include/linux/blkdev.h

+1 −0
Original line number Diff line number Diff line
@@ -405,6 +405,7 @@ struct queue_limits { 
	unsigned short		max_discard_segments;



	unsigned short		max_write_streams;

	unsigned int		write_stream_granularity;



	unsigned int		max_open_zones;

	unsigned int		max_active_zones;