[PATCH v1 7/7] mm/mlock: recharge mlocked pages at culling by vmscan

[Konstantin Khlebnikov]

If mlock cannot catch page in LRU then it isn't moved into unevictable lru.
These pages are 'culled' by reclaimer and moved into unevictable lru.
It seems pages locked with MLOCK_ONFAULT always go through this path.

Reclaimer calls try_to_unmap for already isolated pages, thus on this path
we could freely change page to owner of any mlock vma we found in rmap.

This patch passes flag TTU_LRU_ISOLATED into try_to_ummap to move pages
in mmlock_vma_page().

Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
---
 mm/vmscan.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index bf7a05e8a717..2060f254dd6b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1345,7 +1345,8 @@ static unsigned long shrink_page_list(struct list_head 
*page_list,
                 * processes. Try to unmap it here.
                 */
                if (page_mapped(page)) {
-                       enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH;
+                       enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH |
+                                              TTU_LRU_ISOLATED;
 
                        if (unlikely(PageTransHuge(page)))
                                flags |= TTU_SPLIT_HUGE_PMD;