[PATCH 0/2] mm,swap: skip swap readahead for instant IO (like zswap)

[Rik van Riel]

Both with frontswap/zswap, and with some extremely fast IO devices,
swap IO will be done before the "asynchronous" swap_readpage() call
has returned.

In that case, doing swap readahead only wastes memory, increases
latency, and increases the chances of needing to evict something more
useful from memory. In that case, just skip swap readahead.