This patch defines new APIs to put back the page into previous position of LRU.
The idea I suggested in LSF/MM is simple.
When we try to put back the page into lru list and if friends(prev, next) of the page
still is nearest neighbor, we can insert isolated page into prev's next instead of
head of LRU list. So it keeps LRU history without losing the LRU information.
Cc: KAMEZAWA Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Mel Gorman<mgorman@xxxxxxx>
Cc: Rik van Riel<riel@xxxxxxxxxx>
Cc: Andrea Arcangeli<aarcange@xxxxxxxxxx>
Signed-off-by: Minchan Kim<minchan.kim@xxxxxxxxx>