[RFC 3/8] bail out when the page is in VOLATILE vma

[Minchan Kim <minchan@kernel.org>]

If we found a page is in VOLATILE vma, hurry up discarding
instead of access bit check because it's very unlikey working set.

Next patch will use it.

Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 mm/rmap.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 402d9da..fea01cd 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -695,10 +695,12 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
 		if (!pte)
 			goto out;
 
-		if (vma->vm_flags & VM_LOCKED) {
+		if ((vma->vm_flags & VM_LOCKED) ||
+				(vma->vm_flags & VM_VOLATILE)) {
 			pte_unmap_unlock(pte, ptl);
 			*mapcount = 0;	/* break early from loop */
-			*vm_flags |= VM_LOCKED;
+			*vm_flags |= (vma->vm_flags & VM_LOCKED ?
+					VM_LOCKED : VM_VOLATILE);
 			goto out;
 		}
 
-- 
1.7.9.5

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