Several simple speedups to tmpfs swapoff: without patch, swapoff of a
kernel tree in tmpfs might take take 2 minutes, with patch 4 seconds.
Inline search go no further than necessary; only search inode when it
has swapped pages; start next search from same inode; list in order.

(There's a "list_move_tail" in this patch: not available in 2.5.21,
but I believe you now have it in your ongoing tree.)