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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 /lib/rwsem.c | |
parent | cd43e26f071524647e660706b784ebcbefbd2e44 (diff) | |
download | op-kernel-dev-c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3.zip op-kernel-dev-c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3.tar.gz |
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 'lib/rwsem.c')
0 files changed, 0 insertions, 0 deletions