xfs: use separate btree cursor slab for each btree type

Now that we have the infrastructure to track the max possible height of
each btree type, we can create a separate slab zone for cursors of each
type of btree.  For smaller indices like the free space btrees, this
means that we can pack more cursors into a slab page, improving slab
utilization.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
3 files changed