dm thin: support for non power of 2 pool blocksize
Non power of 2 blocksize support is needed to properly align thinp IO
on storage that has non power of 2 optimal IO sizes (e.g. RAID6 10+2).
Use sector_div to support non power of 2 blocksize for the pool's
data device. This provides comparable performance to the power of 2
math that was performed until now (as tested on modern x86_64 hardware).
The kernel currently assumes that limits->discard_granularity is a power
of two so the thin target only enables discard support if the block
size is a power of two.
Eliminate pool structure's 'block_shift', 'offset_mask' and
remaining 4 byte holes.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 file changed