The get_swap_page/scan_swap_map latency can be so bad that even those without
preemption configured deserve relief: periodically cond_resched.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>