shmem: add page to active list on swapless system

If it's on swapless system, there is no point to add shmem pages
into inactive anonymous LRU list because we couldn't reclaim
them at all.

Meanwhile, MADV_FREE uses inactive anonymous LRU list to quarantine
hinted pages and sweep out them when the memory pressure so shmem
pages are just noise if they stays in inactive anonymous LRU.

This patch add shmem pages into active anonymous LRU list unless
there are swap space.

Signed-off-by: Minchan Kim <>
4 files changed