mm, vmscan: remove balance gap

[cascardo/linux.git] / mm / memory_hotplug.c

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e3cbdca..c527836 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -449,6 +449,25 @@ out_fail:
        return -1;
 }
 
+static struct zone * __meminit move_pfn_range(int zone_shift,
+               unsigned long start_pfn, unsigned long end_pfn)
+{
+       struct zone *zone = page_zone(pfn_to_page(start_pfn));
+       int ret = 0;
+
+       if (zone_shift < 0)
+               ret = move_pfn_range_left(zone + zone_shift, zone,
+                                         start_pfn, end_pfn);
+       else if (zone_shift)
+               ret = move_pfn_range_right(zone, zone + zone_shift,
+                                          start_pfn, end_pfn);
+
+       if (ret)
+               return NULL;
+
+       return zone + zone_shift;
+}
+
 static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
                                      unsigned long end_pfn)
 {
@@ -1028,6 +1047,37 @@ static void node_states_set_node(int node, struct memory_notify *arg)
        node_set_state(node, N_MEMORY);
 }
 
+int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+                  enum zone_type target)
+{
+       struct zone *zone = page_zone(pfn_to_page(pfn));
+       enum zone_type idx = zone_idx(zone);
+       int i;
+
+       if (idx < target) {
+               /* pages must be at end of current zone */
+               if (pfn + nr_pages != zone_end_pfn(zone))
+                       return 0;
+
+               /* no zones in use between current zone and target */
+               for (i = idx + 1; i < target; i++)
+                       if (zone_is_initialized(zone - idx + i))
+                               return 0;
+       }
+
+       if (target < idx) {
+               /* pages must be at beginning of current zone */
+               if (pfn != zone->zone_start_pfn)
+                       return 0;
+
+               /* no zones in use between current zone and target */
+               for (i = target + 1; i < idx; i++)
+                       if (zone_is_initialized(zone - idx + i))
+                               return 0;
+       }
+
+       return target - idx;
+}
 
 /* Must be protected by mem_hotplug_begin() */
 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
@@ -1039,6 +1089,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
        int nid;
        int ret;
        struct memory_notify arg;
+       int zone_shift = 0;
 
        /*
         * This doesn't need a lock to do pfn_to_page().
@@ -1052,19 +1103,14 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
            !can_online_high_movable(zone))
                return -EINVAL;
 
-       if (online_type == MMOP_ONLINE_KERNEL &&
-           zone_idx(zone) == ZONE_MOVABLE) {
-               if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
-                       return -EINVAL;
-       }
-       if (online_type == MMOP_ONLINE_MOVABLE &&
-           zone_idx(zone) == ZONE_MOVABLE - 1) {
-               if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
-                       return -EINVAL;
-       }
+       if (online_type == MMOP_ONLINE_KERNEL)
+               zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
+       else if (online_type == MMOP_ONLINE_MOVABLE)
+               zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
 
-       /* Previous code may changed the zone of the pfn range */
-       zone = page_zone(pfn_to_page(pfn));
+       zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
+       if (!zone)
+               return -EINVAL;
 
        arg.start_pfn = pfn;
        arg.nr_pages = nr_pages;
@@ -1540,7 +1586,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
                        put_page(page);
                        list_add_tail(&page->lru, &source);
                        move_pages--;
-                       inc_zone_page_state(page, NR_ISOLATED_ANON +
+                       inc_node_page_state(page, NR_ISOLATED_ANON +
                                            page_is_file_cache(page));
 
                } else {