r8169: quirk for the 8110sb on arm platform

[sfrench/cifs-2.6.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ff2ebe9458a37ef93c7e4908e1b6156e658c4c75..5d4c4d02254dc977d84951845dada98a80bd0627 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1503,10 +1503,6 @@ module_init(kswapd_init)
  *
  * If non-zero call zone_reclaim when the number of free pages falls below
  * the watermarks.
- *
- * In the future we may add flags to the mode. However, the page allocator
- * should only have to check that zone_reclaim_mode != 0 before calling
- * zone_reclaim().
  */
 int zone_reclaim_mode __read_mostly;
 
@@ -1523,6 +1519,12 @@ int zone_reclaim_mode __read_mostly;
  */
 #define ZONE_RECLAIM_PRIORITY 4
 
+/*
+ * Percentage of pages in a zone that must be unmapped for zone_reclaim to
+ * occur.
+ */
+int sysctl_min_unmapped_ratio = 1;
+
 /*
  * Try to free up some pages from this zone through reclaim.
  */
@@ -1590,18 +1592,17 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
        int node_id;
 
        /*
-        * Do not reclaim if there are not enough reclaimable pages in this
-        * zone that would satify this allocations.
+        * Zone reclaim reclaims unmapped file backed pages.
         *
-        * All unmapped pagecache pages are reclaimable.
-        *
-        * Both counters may be temporarily off a bit so we use
-        * SWAP_CLUSTER_MAX as the boundary. It may also be good to
-        * leave a few frequently used unmapped pagecache pages around.
+        * A small portion of unmapped file backed pages is needed for
+        * file I/O otherwise pages read by file I/O will be immediately
+        * thrown out if the zone is overallocated. So we do not reclaim
+        * if less than a specified percentage of the zone is used by
+        * unmapped file backed pages.
         */
        if (zone_page_state(zone, NR_FILE_PAGES) -
-               zone_page_state(zone, NR_FILE_MAPPED) < SWAP_CLUSTER_MAX)
-                       return 0;
+           zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_ratio)
+               return 0;
 
        /*
         * Avoid concurrent zone reclaims, do not reclaim in a zone that does