This patch adds "swap_token_timeout" parameter in /proc/sys/vm.  The
parameter means expired time of token.  Unit of the value is HZ, and the
default value is the same as current SWAP_TOKEN_TIMEOUT (i.e.  HZ * 300).
Signed-off-by: Hideo Aoki <aoki@sdl.hitachi.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>