mirror_zfs/module
Etienne Dechamps ee5fd0bb80 Set zvol discard_granularity to the volblocksize.
Currently, zvols have a discard granularity set to 0, which suggests to
the upper layer that discard requests of arbirarily small size and
alignment can be made efficiently.

In practice however, ZFS does not handle unaligned discard requests
efficiently: indeed, it is unable to free a part of a block. It will
write zeros to the specified range instead, which is both useless and
inefficient (see dnode_free_range).

With this patch, zvol block devices expose volblocksize as their discard
granularity, so the upper layer is aware that it's not supposed to send
discard requests smaller than volblocksize.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #862
2012-08-07 14:55:31 -07:00
..
avl Add script for builtin module building. 2012-07-26 13:45:09 -07:00
nvpair Add script for builtin module building. 2012-07-26 13:45:09 -07:00
unicode Add script for builtin module building. 2012-07-26 13:45:09 -07:00
zcommon Illumos #1644, #1645, #1646, #1647, #1708 2012-07-31 09:25:30 -07:00
zfs Set zvol discard_granularity to the volblocksize. 2012-08-07 14:55:31 -07:00
zpios Add script for builtin module building. 2012-07-26 13:45:09 -07:00
.gitignore Add .gitignore files to exclude build products 2010-01-08 11:35:17 -08:00
Makefile.in Add script for builtin module building. 2012-07-26 13:45:09 -07:00