1 files changed, 64 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6379ddbffd9b..7da846960d8a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1323,3 +1323,67 @@ static int __init kswapd_init(void)
 }
 
 module_init(kswapd_init)
+
+
+/*
+ * Try to free up some pages from this zone through reclaim.
+ */
+int zone_reclaim(struct zone *zone, unsigned int gfp_mask, unsigned int order)
+{
+        struct scan_control sc;
+        int nr_pages = 1 << order;
+        int total_reclaimed = 0;
+
+        /* The reclaim may sleep, so don't do it if sleep isn't allowed */
+        if (!(gfp_mask & __GFP_WAIT))
+                return 0;
+        if (zone->all_unreclaimable)
+                return 0;
+
+        sc.gfp_mask = gfp_mask;
+        sc.may_writepage = 0;
+        sc.may_swap = 0;
+        sc.nr_mapped = read_page_state(nr_mapped);
+        sc.nr_scanned = 0;
+        sc.nr_reclaimed = 0;
+        /* scan at the highest priority */
+        sc.priority = 0;
+
+        if (nr_pages > SWAP_CLUSTER_MAX)
+                sc.swap_cluster_max = nr_pages;
+        else
+                sc.swap_cluster_max = SWAP_CLUSTER_MAX;
+
+        shrink_zone(zone, &sc);
+        total_reclaimed = sc.nr_reclaimed;
+
+        return total_reclaimed;
+}
+
+asmlinkage long sys_set_zone_reclaim(unsigned int node, unsigned int zone,
+                                     unsigned int state)
+{
+        struct zone *z;
+        int i;
+
+        if (node >= MAX_NUMNODES || !node_online(node))
+                return -EINVAL;
+
+        /* This will break if we ever add more zones */
+        if (!(zone & (1<<ZONE_DMA|1<<ZONE_NORMAL|1<<ZONE_HIGHMEM)))
+                return -EINVAL;
+
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                if (!(zone & 1<<i))
+                        continue;
+
+                z = &NODE_DATA(node)->node_zones[i];
+
+                if (state)
+                        z->reclaim_pages = 1;
+                else
+                        z->reclaim_pages = 0;
+        }
+
+        return 0;
+}