Mark Johnston 915d1b71cd Restore swap pager readahead after r292373.
The removal of vm_fault_additional_pages() meant that a hard fault on
a swap-backed page would result in only that page being read in. This
change implements readahead and readbehind for the swap pager in
swap_pager_getpages(). swap_pager_haspage() is modified to return the
largest contiguous non-resident range of pages containing the requested
range.

Reviewed by:	alc, kib
Tested by:	pho
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D7677
2016-08-30 05:56:21 +00:00
..