Revert "mm: vmscan: fix endless loop in kswapd balancing"

This reverts commit 39d18dc4b8b0c000fa681cbae10ac3f8a132814b which
was commit 60cefed485a02bd99b6299dad70666fe49245da7 upstream.

This was not needed and is not suitable for 3.2.y.

Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1e4ee1acd2b77c408c9528a4b92857799832a573..313381cc88acc83d043d4449b8735592c7a5b270 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2492,19 +2492,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 }
 #endif
 
-static bool zone_balanced(struct zone *zone, int order,
-                         unsigned long balance_gap, int classzone_idx)
-{
-       if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) +
-                                   balance_gap, classzone_idx, 0))
-               return false;
-
-       if (COMPACTION_BUILD && order && !compaction_suitable(zone, order))
-               return false;
-
-       return true;
-}
-
 /*
  * pgdat_balanced is used when checking if a node is balanced for high-order
  * allocations. Only zones that meet watermarks and are in a zone allowed
@@ -2564,7 +2551,8 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
                        continue;
                }
 
-               if (!zone_balanced(zone, order, 0, i))
+               if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
+                                                       i, 0))
                        all_zones_ok = false;
                else
                        balanced += zone->present_pages;
@@ -2667,7 +2655,8 @@ loop_again:
                                shrink_active_list(SWAP_CLUSTER_MAX, zone,
                                                        &sc, priority, 0);
 
-                       if (!zone_balanced(zone, order, 0, 0)) {
+                       if (!zone_watermark_ok_safe(zone, order,
+                                       high_wmark_pages(zone), 0, 0)) {
                                end_zone = i;
                                break;
                        } else {
@@ -2728,8 +2717,9 @@ loop_again:
                                (zone->present_pages +
                                        KSWAPD_ZONE_BALANCE_GAP_RATIO-1) /
                                KSWAPD_ZONE_BALANCE_GAP_RATIO);
-                       if (!zone_balanced(zone, order,
-                                          balance_gap, end_zone)) {
+                       if (!zone_watermark_ok_safe(zone, order,
+                                       high_wmark_pages(zone) + balance_gap,
+                                       end_zone, 0)) {
                                shrink_zone(priority, zone, &sc);
 
                                reclaim_state->reclaimed_slab = 0;
@@ -2756,7 +2746,8 @@ loop_again:
                                continue;
                        }
 
-                       if (!zone_balanced(zone, order, 0, end_zone)) {
+                       if (!zone_watermark_ok_safe(zone, order,
+                                       high_wmark_pages(zone), end_zone, 0)) {
                                all_zones_ok = 0;
                                /*
                                 * We are still under min water mark.  This