kib 23dcf48f60 Add FFS pager, which uses buffer cache read operation to validate pages. ... See the comments for more detailed description of the algorithm. The pager is used unconditionally when the block size of the underlying device is larger than the machine page size, since local vnode pager cannot handle the configuration [1]. Otherwise, the vfs.ffs.use_buf_pager sysctl allows to switch to the local pager. Measurements demonstrated no regression in the ever-important buildworld benchmark, and small (~5%) throughput improvements in the special microbenchmark configuration for dbench over swap-backed md(4). Code can be generalized and reused for other filesystems which use buffer cache. Reported by: Anton Yuzhaninov <citrin@citrin.ru> [1] Tested by: pho Benchmarked by: mjg, pho Reviewed by: alc, markj, mckusick (previous version) Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D8198		2016-10-19 11:09:29 +00:00
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ffs	Add FFS pager, which uses buffer cache read operation to validate pages.	2016-10-19 11:09:29 +00:00
ufs	Be more strict when selecting between snapshot/regular mount.	2016-09-19 15:58:33 +00:00