__put_compound_page() calls __page_cache_release() to do some freeing works,
but it's obviously for thps, not for hugetlb. We didn't care it because PageLRU
is always cleared and page->mem_cgroup is always NULL for hugetlb.
But it's not correct and has potential risks, so let's make it conditional.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
mm/swap.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git v4.0-rc6.orig/mm/swap.c v4.0-rc6/mm/swap.c
index cd3a5e64cea9..8e46823c3319 100644
--- v4.0-rc6.orig/mm/swap.c
+++ v4.0-rc6/mm/swap.c
@@ -31,6 +31,7 @@
#include <linux/memcontrol.h>
#include <linux/gfp.h>
#include <linux/uio.h>
+#include <linux/hugetlb.h>
#include "internal.h"
@@ -75,7 +76,14 @@ static void __put_compound_page(struct page *page)
{
compound_page_dtor *dtor;
- __page_cache_release(page);
+ /*
+ * __page_cache_release() is supposed to be called for thp, not for
+ * hugetlb. This is because hugetlb page does never have PageLRU set
+ * (it's never listed to any LRU lists) and no memcg routines should
+ * be called for hugetlb (it has a separate hugetlb_cgroup.)
+ */
+ if (!PageHuge(page))
+ __page_cache_release(page);
dtor = get_compound_page_dtor(page);
(*dtor)(page);
}
--
1.9.3
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