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author | Martin K. Petersen <martin.petersen@oracle.com> | 2009-05-22 17:17:53 -0400 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2009-05-22 23:22:55 +0200 |
commit | c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3 (patch) | |
tree | a83f7540cc894caafe74db911cba3998d6a9a164 /block/blk-sysfs.c | |
parent | cd43e26f071524647e660706b784ebcbefbd2e44 (diff) | |
download | lwn-c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3.tar.gz lwn-c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3.zip |
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 <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-sysfs.c')
-rw-r--r-- | block/blk-sysfs.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 3ccdadb8e204..9337e17f9110 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, |