1 files changed, 29 insertions, 1 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 5ed471b58f4f..f5fa3082fd6a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -12,6 +12,7 @@
 #include <linux/threads.h>
 #include <linux/numa.h>
 #include <linux/init.h>
+#include <linux/seqlock.h>
 #include <asm/atomic.h>
 
 /* Free memory management - zoned buddy allocator.  */
@@ -137,6 +138,10 @@ struct zone {
          * free areas of different sizes
          */
         spinlock_t              lock;
+#ifdef CONFIG_MEMORY_HOTPLUG
+        /* see spanned/present_pages for more description */
+        seqlock_t               span_seqlock;
+#endif
         struct free_area        free_area[MAX_ORDER];
 
 
@@ -220,6 +225,16 @@ struct zone {
         /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
         unsigned long           zone_start_pfn;
 
+        /*
+         * zone_start_pfn, spanned_pages and present_pages are all
+         * protected by span_seqlock.  It is a seqlock because it has
+         * to be read outside of zone->lock, and it is done in the main
+         * allocator path.  But, it is written quite infrequently.
+         *
+         * The lock is declared along with zone->lock because it is
+         * frequently read in proximity to zone->lock.  It's good to
+         * give them a chance of being in the same cacheline.
+         */
         unsigned long           spanned_pages;  /* total size, including holes */
         unsigned long           present_pages;  /* amount of memory (excluding holes) */
 
@@ -273,6 +288,16 @@ typedef struct pglist_data {
         struct page *node_mem_map;
 #endif
         struct bootmem_data *bdata;
+#ifdef CONFIG_MEMORY_HOTPLUG
+        /*
+         * Must be held any time you expect node_start_pfn, node_present_pages
+         * or node_spanned_pages stay constant.  Holding this will also
+         * guarantee that any pfn_valid() stays that way.
+         *
+         * Nests above zone->lock and zone->size_seqlock.
+         */
+        spinlock_t node_size_lock;
+#endif
         unsigned long node_start_pfn;
         unsigned long node_present_pages; /* total number of physical pages */
         unsigned long node_spanned_pages; /* total size of physical page
@@ -293,6 +318,8 @@ typedef struct pglist_data {
 #endif
 #define nid_page_nr(nid, pagenr)        pgdat_page_nr(NODE_DATA(nid),(pagenr))
 
+#include <linux/memory_hotplug.h>
+
 extern struct pglist_data *pgdat_list;
 
 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
@@ -302,7 +329,7 @@ void get_zone_counts(unsigned long *active, unsigned long *inactive,
 void build_all_zonelists(void);
 void wakeup_kswapd(struct zone *zone, int order);
 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
-                int alloc_type, int can_try_harder, int gfp_high);
+                int alloc_type, int can_try_harder, gfp_t gfp_high);
 
 #ifdef CONFIG_HAVE_MEMORY_PRESENT
 void memory_present(int nid, unsigned long start, unsigned long end);
@@ -509,6 +536,7 @@ static inline struct mem_section *__nr_to_section(unsigned long nr)
                 return NULL;
         return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
 }
+extern int __section_nr(struct mem_section* ms);
 
 /*
  * We use the lower bits of the mem_map pointer to store