V13->V14
- Rediff against linux-next on request of Andrew
- TestSetPageLocked -> trylock_page conversion.
Slab fragmentation is mainly an issue if Linux is used as a fileserver
and large amounts of dentries, inodes and buffer heads accumulate. In some
load situations the slabs become very sparsely populated so that a lot of
memory is wasted by slabs that only contain one or a few objects. In
extreme cases the performance of a machine will become sluggish since
we are continually running reclaim without much succes.
Slab defragmentation adds the capability to recover the memory that
is wasted.