mm: workingset: #define radix entry eviction mask

This is a compile-time constant, no need to calculate it on refault.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/mm/workingset.c b/mm/workingset.c
index 61ead9e5549d..3ef92f6e41fe 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -152,6 +152,10 @@
  * refault distance will immediately activate the refaulting page.
  */
 
+#define EVICTION_SHIFT  (RADIX_TREE_EXCEPTIONAL_ENTRY + \
+                         ZONES_SHIFT + NODES_SHIFT)
+#define EVICTION_MASK   (~0UL >> EVICTION_SHIFT)
+
 static void *pack_shadow(unsigned long eviction, struct zone *zone)
 {
         eviction = (eviction << NODES_SHIFT) | zone_to_nid(zone);
@@ -168,7 +172,6 @@ static void unpack_shadow(void *shadow,
         unsigned long entry = (unsigned long)shadow;
         unsigned long eviction;
         unsigned long refault;
-        unsigned long mask;
         int zid, nid;
 
         entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT;
@@ -181,8 +184,7 @@ static void unpack_shadow(void *shadow,
         *zone = NODE_DATA(nid)->node_zones + zid;
 
         refault = atomic_long_read(&(*zone)->inactive_age);
-        mask = ~0UL >> (NODES_SHIFT + ZONES_SHIFT +
-                        RADIX_TREE_EXCEPTIONAL_SHIFT);
+
         /*
          * The unsigned subtraction here gives an accurate distance
          * across inactive_age overflows in most cases.
@@ -199,7 +201,7 @@ static void unpack_shadow(void *shadow,
          * inappropriate activation leading to pressure on the active
          * list is not a problem.
          */
-        *distance = (refault - eviction) & mask;
+        *distance = (refault - eviction) & EVICTION_MASK;
 }
 
 /**