2 files changed, 38 insertions, 0 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 074eb98fe15..375e79eb009 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -54,6 +54,15 @@ struct page {
                 union {
                         pgoff_t index;          /* Our offset within mapping. */
                         void *freelist;         /* slub/slob first free object */
+                        bool pfmemalloc;        /* If set by the page allocator,
+                                                 * ALLOC_PFMEMALLOC was set
+                                                 * and the low watermark was not
+                                                 * met implying that the system
+                                                 * is under some pressure. The
+                                                 * caller should try ensure
+                                                 * this page is only used to
+                                                 * free other pages.
+                                                 */
                 };
 
                 union {
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index c88d2a9451a..b5d13841604 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -7,6 +7,7 @@
 
 #include <linux/types.h>
 #include <linux/bug.h>
+#include <linux/mmdebug.h>
 #ifndef __GENERATING_BOUNDS_H
 #include <linux/mm_types.h>
 #include <generated/bounds.h>
@@ -453,6 +454,34 @@ static inline int PageTransTail(struct page *page)
 }
 #endif
 
+/*
+ * If network-based swap is enabled, sl*b must keep track of whether pages
+ * were allocated from pfmemalloc reserves.
+ */
+static inline int PageSlabPfmemalloc(struct page *page)
+{
+        VM_BUG_ON(!PageSlab(page));
+        return PageActive(page);
+}
+
+static inline void SetPageSlabPfmemalloc(struct page *page)
+{
+        VM_BUG_ON(!PageSlab(page));
+        SetPageActive(page);
+}
+
+static inline void __ClearPageSlabPfmemalloc(struct page *page)
+{
+        VM_BUG_ON(!PageSlab(page));
+        __ClearPageActive(page);
+}
+
+static inline void ClearPageSlabPfmemalloc(struct page *page)
+{
+        VM_BUG_ON(!PageSlab(page));
+        ClearPageActive(page);
+}
+
 #ifdef CONFIG_MMU
 #define __PG_MLOCKED            (1 << PG_mlocked)
 #else