path: root/mm/memory.c
diff options
authorDavid Rientjes <>2012-10-08 16:34:03 -0700
committerLinus Torvalds <>2012-10-09 16:23:02 +0900
commitb676b293fb48672904ee1b9828cb50b4eed01717 (patch)
tree22b2dcc1623da40a5ddfaf6db2bc5ab1c2476ddb /mm/memory.c
parente90bdb7f52f94204c78fb40b0804645defdebd71 (diff)
mm, thp: fix mapped pages avoiding unevictable list on mlock
When a transparent hugepage is mapped and it is included in an mlock() range, follow_page() incorrectly avoids setting the page's mlock bit and moving it to the unevictable lru. This is evident if you try to mlock(), munlock(), and then mlock() a range again. Currently: #define MAP_SIZE (4 << 30) /* 4GB */ void *ptr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); mlock(ptr, MAP_SIZE); $ grep -E "Unevictable|Inactive\(anon" /proc/meminfo Inactive(anon): 6304 kB Unevictable: 4213924 kB munlock(ptr, MAP_SIZE); Inactive(anon): 4186252 kB Unevictable: 19652 kB mlock(ptr, MAP_SIZE); Inactive(anon): 4198556 kB Unevictable: 21684 kB Notice that less than 2MB was added to the unevictable list; this is because these pages in the range are not transparent hugepages since the 4GB range was allocated with mmap() and has no specific alignment. If posix_memalign() were used instead, unevictable would not have grown at all on the second mlock(). The fix is to call mlock_vma_page() so that the mlock bit is set and the page is added to the unevictable list. With this patch: mlock(ptr, MAP_SIZE); Inactive(anon): 4056 kB Unevictable: 4213940 kB munlock(ptr, MAP_SIZE); Inactive(anon): 4198268 kB Unevictable: 19636 kB mlock(ptr, MAP_SIZE); Inactive(anon): 4008 kB Unevictable: 4213940 kB Signed-off-by: David Rientjes <> Acked-by: Hugh Dickins <> Reviewed-by: Andrea Arcangeli <> Cc: Naoya Horiguchi <> Cc: KAMEZAWA Hiroyuki <> Cc: Johannes Weiner <> Cc: Michel Lespinasse <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/memory.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 45bb6d296b6f..fb135ba4aba9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1528,7 +1528,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
wait_split_huge_page(vma->anon_vma, pmd);
} else {
- page = follow_trans_huge_pmd(mm, address,
+ page = follow_trans_huge_pmd(vma, address,
pmd, flags);
goto out;