K 10
svn:author
V 3
alc
K 8
svn:date
V 27
2016-07-07T20:58:16.712227Z
K 7
svn:log
V 748
Change the type of the map entry's next_read field from a vm_pindex_t to a
vm_offset_t.  (This field is used to detect sequential access to the virtual
address range represented by the map entry.)  There are three reasons to
make this change.  First, a vm_offset_t is smaller on 32-bit architectures.
Consequently, a struct vm_map_entry is now smaller on 32-bit architectures.
Second, a vm_offset_t can be written atomically, whereas it may not be
possible to write a vm_pindex_t atomically on a 32-bit architecture.  Third,
using a vm_pindex_t makes the next_read field dependent on which object in
the shadow chain is being read from.

Replace an "XXX" comment.

Reviewed by:	kib
Approved by:	re (gjb)
Sponsored by:	EMC / Isilon Storage Division

END