1 files changed, 14 insertions, 13 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 845b91749a42..3c5cf664abd2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2397,13 +2397,18 @@ void setup_per_zone_pages_min(void)
         }
 
         for_each_zone(zone) {
+                unsigned long tmp;
                 spin_lock_irqsave(&zone->lru_lock, flags);
+                tmp = (pages_min * zone->present_pages) / lowmem_pages;
                 if (is_highmem(zone)) {
                         /*
-                         * Often, highmem doesn't need to reserve any pages.
-                         * But the pages_min/low/high values are also used for
-                         * batching up page reclaim activity so we need a
-                         * decent value here.
+                         * __GFP_HIGH and PF_MEMALLOC allocations usually don't
+                         * need highmem pages, so cap pages_min to a small
+                         * value here.
+                         *
+                         * The (pages_high-pages_low) and (pages_low-pages_min)
+                         * deltas controls asynch page reclaim, and so should
+                         * not be capped for highmem.
                          */
                         int min_pages;
 
@@ -2414,19 +2419,15 @@ void setup_per_zone_pages_min(void)
                                 min_pages = 128;
                         zone->pages_min = min_pages;
                 } else {
-                        /* if it's a lowmem zone, reserve a number of pages
+                        /*
+                         * If it's a lowmem zone, reserve a number of pages
                          * proportionate to the zone's size.
                          */
-                        zone->pages_min = (pages_min * zone->present_pages) /
-                                           lowmem_pages;
+                        zone->pages_min = tmp;
                 }
 
-                /*
-                 * When interpreting these watermarks, just keep in mind that:
-                 * zone->pages_min == (zone->pages_min * 4) / 4;
-                 */
-                zone->pages_low   = (zone->pages_min * 5) / 4;
-                zone->pages_high  = (zone->pages_min * 6) / 4;
+                zone->pages_low   = zone->pages_min + tmp / 4;
+                zone->pages_high  = zone->pages_min + tmp / 2;
                 spin_unlock_irqrestore(&zone->lru_lock, flags);
         }
 }