[PATCH] overcommit: add calculate_totalreserve_pages()

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

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b8165e0..97d6827 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -51,6 +51,7 @@ nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
 EXPORT_SYMBOL(node_possible_map);
 unsigned long totalram_pages __read_mostly;
 unsigned long totalhigh_pages __read_mostly;
+unsigned long totalreserve_pages __read_mostly;
 long nr_swap_pages;
 int percpu_pagelist_fraction;
 
@@ -2476,6 +2477,38 @@ void __init page_alloc_init(void)
        hotcpu_notifier(page_alloc_cpu_notify, 0);
 }
 
+/*
+ * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
+ *     or min_free_kbytes changes.
+ */
+static void calculate_totalreserve_pages(void)
+{
+       struct pglist_data *pgdat;
+       unsigned long reserve_pages = 0;
+       int i, j;
+
+       for_each_online_pgdat(pgdat) {
+               for (i = 0; i < MAX_NR_ZONES; i++) {
+                       struct zone *zone = pgdat->node_zones + i;
+                       unsigned long max = 0;
+
+                       /* Find valid and maximum lowmem_reserve in the zone */
+                       for (j = i; j < MAX_NR_ZONES; j++) {
+                               if (zone->lowmem_reserve[j] > max)
+                                       max = zone->lowmem_reserve[j];
+                       }
+
+                       /* we treat pages_high as reserved pages. */
+                       max += zone->pages_high;
+
+                       if (max > zone->present_pages)
+                               max = zone->present_pages;
+                       reserve_pages += max;
+               }
+       }
+       totalreserve_pages = reserve_pages;
+}
+
 /*
  * setup_per_zone_lowmem_reserve - called whenever
  *     sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
@@ -2507,6 +2540,9 @@ static void setup_per_zone_lowmem_reserve(void)
                        }
                }
        }
+
+       /* update totalreserve_pages */
+       calculate_totalreserve_pages();
 }
 
 /*
@@ -2561,6 +2597,9 @@ void setup_per_zone_pages_min(void)
                zone->pages_high  = zone->pages_min + tmp / 2;
                spin_unlock_irqrestore(&zone->lru_lock, flags);
        }
+
+       /* update totalreserve_pages */
+       calculate_totalreserve_pages();
 }
 
 /*