mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low...

[linux-imx.git] / include / linux / mmzone.h

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index b4d109e389b806f205aa1575135001e09a864bf5..8b2db3d65564f3d9a0028528844425f46c7dc9b5 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -283,6 +283,13 @@ struct zone {
        /* zone watermarks, access with *_wmark_pages(zone) macros */
        unsigned long watermark[NR_WMARK];
 
+       /*
+        * When free pages are below this point, additional steps are taken
+        * when reading the number of free pages to avoid per-cpu counter
+        * drift allowing watermarks to be breached
+        */
+       unsigned long percpu_drift_mark;
+
        /*
         * We don't know if the memory that we're going to allocate will be freeable
         * or/and it will be released eventually, so to avoid totally wasting several
@@ -456,6 +463,12 @@ static inline int zone_is_oom_locked(const struct zone *zone)
        return test_bit(ZONE_OOM_LOCKED, &zone->flags);
 }
 
+#ifdef CONFIG_SMP
+unsigned long zone_nr_free_pages(struct zone *zone);
+#else
+#define zone_nr_free_pages(zone) zone_page_state(zone, NR_FREE_PAGES)
+#endif /* CONFIG_SMP */
+
 /*
  * The "priority" of VM scanning is how much of the queues we will scan in one
  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the