Commonly, putback_lru_page is used with isolated_lru_page.
The isolated_lru_page picks the page in middle of LRU and
putback_lru_page insert the lru in head of LRU.
It means it could make LRU churning so we have to be very careful.
Let's clear description of isolate/putback functions.
Cc: Mel Gorman<mgorman@xxxxxxx>
Cc: Rik van Riel<riel@xxxxxxxxxx>
Cc: Andrea Arcangeli<aarcange@xxxxxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx>
Acked-by: Johannes Weiner<hannes@xxxxxxxxxxx>
Reviewed-by: KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim<minchan.kim@xxxxxxxxx>