From c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 22 May 2009 17:17:53 -0400 Subject: block: Export I/O topology for block devices and partitions To support devices with physical block sizes bigger than 512 bytes we need to ensure proper alignment. This patch adds support for exposing I/O topology characteristics as devices are stacked. logical_block_size is the smallest unit the device can address. physical_block_size indicates the smallest I/O the device can write without incurring a read-modify-write penalty. The io_min parameter is the smallest preferred I/O size reported by the device. In many cases this is the same as the physical block size. However, the io_min parameter can be scaled up when stacking (RAID5 chunk size > physical block size). The io_opt characteristic indicates the optimal I/O size reported by the device. This is usually the stripe width for arrays. The alignment_offset parameter indicates the number of bytes the start of the device/partition is offset from the device's natural alignment. Partition tools and MD/DM utilities can use this to pad their offsets so filesystems start on proper boundaries. Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- block/blk-sysfs.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'block/blk-sysfs.c') diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 3ccdadb8e20..9337e17f911 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -105,6 +105,21 @@ static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page return queue_var_show(queue_logical_block_size(q), page); } +static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page) +{ + return queue_var_show(queue_physical_block_size(q), page); +} + +static ssize_t queue_io_min_show(struct request_queue *q, char *page) +{ + return queue_var_show(queue_io_min(q), page); +} + +static ssize_t queue_io_opt_show(struct request_queue *q, char *page) +{ + return queue_var_show(queue_io_opt(q), page); +} + static ssize_t queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) { @@ -257,6 +272,21 @@ static struct queue_sysfs_entry queue_logical_block_size_entry = { .show = queue_logical_block_size_show, }; +static struct queue_sysfs_entry queue_physical_block_size_entry = { + .attr = {.name = "physical_block_size", .mode = S_IRUGO }, + .show = queue_physical_block_size_show, +}; + +static struct queue_sysfs_entry queue_io_min_entry = { + .attr = {.name = "minimum_io_size", .mode = S_IRUGO }, + .show = queue_io_min_show, +}; + +static struct queue_sysfs_entry queue_io_opt_entry = { + .attr = {.name = "optimal_io_size", .mode = S_IRUGO }, + .show = queue_io_opt_show, +}; + static struct queue_sysfs_entry queue_nonrot_entry = { .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR }, .show = queue_nonrot_show, @@ -289,6 +319,9 @@ static struct attribute *default_attrs[] = { &queue_iosched_entry.attr, &queue_hw_sector_size_entry.attr, &queue_logical_block_size_entry.attr, + &queue_physical_block_size_entry.attr, + &queue_io_min_entry.attr, + &queue_io_opt_entry.attr, &queue_nonrot_entry.attr, &queue_nomerges_entry.attr, &queue_rq_affinity_entry.attr, -- cgit v1.2.3