e05aad2d33
This adds TRIM support to cache vdevs. When ARC buffers are removed
from the L2ARC in arc_hdr_destroy(), arc_release() or l2arc_evict(),
the size previously occupied by the buffer gets scheduled for TRIMming.
As always, actual TRIMs are only issued to the L2ARC after
txg_trim_limit.
Reviewed by: pjd (mentor)
Approved by: pjd (mentor)
Obtained from: 31aae37399
MFC after: 2 weeks