"Ingo Molnar reviewed Con Kolivas's swap-prefetching patches
suggesting that they were ready for inclusion in the mainline
kernel, 'I've reviewed it once again and in the
!CONFIG_SWAP_PREFETCH case it's a clear NOP, while in the
CONFIG_SWAP_PREFETCH=y case all the feedback i've seen so far was
positive. Time to have this upstream and time for a
desktop-oriented distro to pick it up.' He went on to describe swap
prefetch, 'to the desktop user this is a speculative performance
feature that he is willing to potentially waste CPU and IO
capacity, in expectation of better performance. On the conceptual
level it is _precisely the same thing as regular file readahead_.
(with the difference that to me swapahead seems to be quite a bit
more intelligent than our current file readahead logic...)'"