1 files changed, 26 insertions, 25 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8485735fc690..abe26003124d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1150,10 +1150,15 @@ failed:
         return NULL;
 }
 
-#define ALLOC_NO_WATERMARKS     0x01 /* don't check watermarks at all */
-#define ALLOC_WMARK_MIN         0x02 /* use pages_min watermark */
-#define ALLOC_WMARK_LOW         0x04 /* use pages_low watermark */
-#define ALLOC_WMARK_HIGH        0x08 /* use pages_high watermark */
+/* The ALLOC_WMARK bits are used as an index to zone->watermark */
+#define ALLOC_WMARK_MIN         WMARK_MIN
+#define ALLOC_WMARK_LOW         WMARK_LOW
+#define ALLOC_WMARK_HIGH        WMARK_HIGH
+#define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
+
+/* Mask to get the watermark bits */
+#define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
+
 #define ALLOC_HARDER            0x10 /* try to alloc harder */
 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
@@ -1440,14 +1445,10 @@ zonelist_scan:
                         !cpuset_zone_allowed_softwall(zone, gfp_mask))
                                 goto try_next_zone;
 
+                BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
                 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
                         unsigned long mark;
-                        if (alloc_flags & ALLOC_WMARK_MIN)
-                                mark = zone->pages_min;
-                        else if (alloc_flags & ALLOC_WMARK_LOW)
-                                mark = zone->pages_low;
-                        else
-                                mark = zone->pages_high;
+                        mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
                         if (!zone_watermark_ok(zone, order, mark,
                                     classzone_idx, alloc_flags)) {
                                 if (!zone_reclaim_mode ||
@@ -1959,7 +1960,7 @@ static unsigned int nr_free_zone_pages(int offset)
 
         for_each_zone_zonelist(zone, z, zonelist, offset) {
                 unsigned long size = zone->present_pages;
-                unsigned long high = zone->pages_high;
+                unsigned long high = high_wmark_pages(zone);
                 if (size > high)
                         sum += size - high;
         }
@@ -2096,9 +2097,9 @@ void show_free_areas(void)
                         "\n",
                         zone->name,
                         K(zone_page_state(zone, NR_FREE_PAGES)),
-                        K(zone->pages_min),
-                        K(zone->pages_low),
-                        K(zone->pages_high),
+                        K(min_wmark_pages(zone)),
+                        K(low_wmark_pages(zone)),
+                        K(high_wmark_pages(zone)),
                         K(zone_page_state(zone, NR_ACTIVE_ANON)),
                         K(zone_page_state(zone, NR_INACTIVE_ANON)),
                         K(zone_page_state(zone, NR_ACTIVE_FILE)),
@@ -2702,8 +2703,8 @@ static inline unsigned long wait_table_bits(unsigned long size)
 
 /*
  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
- * of blocks reserved is based on zone->pages_min. The memory within the
- * reserve will tend to store contiguous free pages. Setting min_free_kbytes
+ * of blocks reserved is based on min_wmark_pages(zone). The memory within
+ * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
  * higher will lead to a bigger reserve which will get freed as contiguous
  * blocks as reclaim kicks in
  */
@@ -2716,7 +2717,7 @@ static void setup_zone_migrate_reserve(struct zone *zone)
         /* Get the start pfn, end pfn and the number of blocks to reserve */
         start_pfn = zone->zone_start_pfn;
         end_pfn = start_pfn + zone->spanned_pages;
-        reserve = roundup(zone->pages_min, pageblock_nr_pages) >>
+        reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
                                                         pageblock_order;
 
         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
@@ -4319,8 +4320,8 @@ static void calculate_totalreserve_pages(void)
                                         max = zone->lowmem_reserve[j];
                         }
 
-                        /* we treat pages_high as reserved pages. */
-                        max += zone->pages_high;
+                        /* we treat the high watermark as reserved pages. */
+                        max += high_wmark_pages(zone);
 
                         if (max > zone->present_pages)
                                 max = zone->present_pages;
@@ -4400,7 +4401,7 @@ void setup_per_zone_pages_min(void)
                          * need highmem pages, so cap pages_min to a small
                          * value here.
                          *
-                         * The (pages_high-pages_low) and (pages_low-pages_min)
+                         * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
                          * deltas controls asynch page reclaim, and so should
                          * not be capped for highmem.
                          */
@@ -4411,17 +4412,17 @@ void setup_per_zone_pages_min(void)
                                 min_pages = SWAP_CLUSTER_MAX;
                         if (min_pages > 128)
                                 min_pages = 128;
-                        zone->pages_min = min_pages;
+                        zone->watermark[WMARK_MIN] = min_pages;
                 } else {
                         /*
                          * If it's a lowmem zone, reserve a number of pages
                          * proportionate to the zone's size.
                          */
-                        zone->pages_min = tmp;
+                        zone->watermark[WMARK_MIN] = tmp;
                 }
 
-                zone->pages_low   = zone->pages_min + (tmp >> 2);
-                zone->pages_high  = zone->pages_min + (tmp >> 1);
+                zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
+                zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
                 setup_zone_migrate_reserve(zone);
                 spin_unlock_irqrestore(&zone->lock, flags);
         }
@@ -4566,7 +4567,7 @@ int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
  *      whenever sysctl_lowmem_reserve_ratio changes.
  *
  * The reserve ratio obviously has absolutely no relation with the
- * pages_min watermarks. The lowmem reserve ratio can only make sense
+ * minimum watermarks. The lowmem reserve ratio can only make sense
  * if in function of the boot time zone sizes.
  */
 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,