4 files changed, 59 insertions, 44 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d538de901965..ab6e4974f379 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -396,7 +396,9 @@ void split_page(struct page *page, unsigned int order);
  * We are going to use the flags for the page to node mapping if its in
  * there.  This includes the case where there is no node, so it is implicit.
  */
-#define FLAGS_HAS_NODE          (NODES_WIDTH > 0 || NODES_SHIFT == 0)
+#if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
+#define NODE_NOT_IN_PAGE_FLAGS
+#endif
 
 #ifndef PFN_SECTION_SHIFT
 #define PFN_SECTION_SHIFT 0
@@ -411,13 +413,18 @@ void split_page(struct page *page, unsigned int order);
 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
 
-/* NODE:ZONE or SECTION:ZONE is used to lookup the zone from a page. */
-#if FLAGS_HAS_NODE
-#define ZONETABLE_SHIFT         (NODES_SHIFT + ZONES_SHIFT)
+/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allcator */
+#ifdef NODE_NOT_IN_PAGEFLAGS
+#define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
 #else
-#define ZONETABLE_SHIFT         (SECTIONS_SHIFT + ZONES_SHIFT)
+#define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
+#endif
+
+#if ZONES_WIDTH > 0
+#define ZONEID_PGSHIFT          ZONES_PGSHIFT
+#else
+#define ZONEID_PGSHIFT          NODES_PGOFF
 #endif
-#define ZONETABLE_PGSHIFT       ZONES_PGSHIFT
 
 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
@@ -426,23 +433,25 @@ void split_page(struct page *page, unsigned int order);
 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
-#define ZONETABLE_MASK          ((1UL << ZONETABLE_SHIFT) - 1)
+#define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
 
 static inline enum zone_type page_zonenum(struct page *page)
 {
         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
 }
 
-struct zone;
-extern struct zone *zone_table[];
-
+/*
+ * The identification function is only used by the buddy allocator for
+ * determining if two pages could be buddies. We are not really
+ * identifying a zone since we could be using a the section number
+ * id if we have not node id available in page flags.
+ * We guarantee only that it will return the same value for two
+ * combinable pages in a zone.
+ */
 static inline int page_zone_id(struct page *page)
 {
-        return (page->flags >> ZONETABLE_PGSHIFT) & ZONETABLE_MASK;
-}
-static inline struct zone *page_zone(struct page *page)
-{
-        return zone_table[page_zone_id(page)];
+        BUILD_BUG_ON(ZONEID_PGSHIFT == 0 && ZONEID_MASK);
+        return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
 }
 
 static inline unsigned long zone_to_nid(struct zone *zone)
@@ -454,13 +463,20 @@ static inline unsigned long zone_to_nid(struct zone *zone)
 #endif
 }
 
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+extern unsigned long page_to_nid(struct page *page);
+#else
 static inline unsigned long page_to_nid(struct page *page)
 {
-        if (FLAGS_HAS_NODE)
-                return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
-        else
-                return zone_to_nid(page_zone(page));
+        return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
 }
+#endif
+
+static inline struct zone *page_zone(struct page *page)
+{
+        return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
+}
+
 static inline unsigned long page_to_section(struct page *page)
 {
         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
@@ -477,6 +493,7 @@ static inline void set_page_node(struct page *page, unsigned long node)
         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
 }
+
 static inline void set_page_section(struct page *page, unsigned long section)
 {
         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
@@ -947,8 +964,6 @@ extern void mem_init(void);
 extern void show_mem(void);
 extern void si_meminfo(struct sysinfo * val);
 extern void si_meminfo_node(struct sysinfo *val, int nid);
-extern void zonetable_add(struct zone *zone, int nid, enum zone_type zid,
-                                        unsigned long pfn, unsigned long size);
 
 #ifdef CONFIG_NUMA
 extern void setup_per_cpu_pageset(void);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index fd678a662eae..0c055a090f4d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -72,7 +72,6 @@ static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
                         return ret;
         }
         memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
-        zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages);
         return 0;
 }
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 08360aa111f9..23bc5bcbdcf9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -83,13 +83,6 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
 
 EXPORT_SYMBOL(totalram_pages);
 
-/*
- * Used by page_zone() to look up the address of the struct zone whose
- * id is encoded in the upper bits of page->flags
- */
-struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
-EXPORT_SYMBOL(zone_table);
-
 static char *zone_names[MAX_NR_ZONES] = {
          "DMA",
 #ifdef CONFIG_ZONE_DMA32
@@ -1715,20 +1708,6 @@ void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
         }
 }
 
-#define ZONETABLE_INDEX(x, zone_nr)     ((x << ZONES_SHIFT) | zone_nr)
-void zonetable_add(struct zone *zone, int nid, enum zone_type zid,
-                unsigned long pfn, unsigned long size)
-{
-        unsigned long snum = pfn_to_section_nr(pfn);
-        unsigned long end = pfn_to_section_nr(pfn + size);
-
-        if (FLAGS_HAS_NODE)
-                zone_table[ZONETABLE_INDEX(nid, zid)] = zone;
-        else
-                for (; snum <= end; snum++)
-                        zone_table[ZONETABLE_INDEX(snum, zid)] = zone;
-}
-
 #ifndef __HAVE_ARCH_MEMMAP_INIT
 #define memmap_init(size, nid, zone, start_pfn) \
         memmap_init_zone((size), (nid), (zone), (start_pfn))
@@ -2421,7 +2400,6 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                 if (!size)
                         continue;
 
-                zonetable_add(zone, nid, j, zone_start_pfn, size);
                 ret = init_currently_empty_zone(zone, zone_start_pfn, size);
                 BUG_ON(ret);
                 zone_start_pfn += size;
diff --git a/mm/sparse.c b/mm/sparse.c
index b3c82ba30012..158d6a2a5263 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -24,6 +24,25 @@ struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
 #endif
 EXPORT_SYMBOL(mem_section);
 
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+/*
+ * If we did not store the node number in the page then we have to
+ * do a lookup in the section_to_node_table in order to find which
+ * node the page belongs to.
+ */
+#if MAX_NUMNODES <= 256
+static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
+#else
+static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
+#endif
+
+unsigned long page_to_nid(struct page *page)
+{
+        return section_to_node_table[page_to_section(page)];
+}
+EXPORT_SYMBOL(page_to_nid);
+#endif
+
 #ifdef CONFIG_SPARSEMEM_EXTREME
 static struct mem_section *sparse_index_alloc(int nid)
 {
@@ -49,6 +68,10 @@ static int sparse_index_init(unsigned long section_nr, int nid)
         struct mem_section *section;
         int ret = 0;
 
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+        section_to_node_table[section_nr] = nid;
+#endif
+
         if (mem_section[root])
                 return -EEXIST;