cma: fix counting of isolated pages

Isolated free pages shouldn't be accounted to NR_FREE_PAGES counter.  Fix
it by properly decreasing/increasing NR_FREE_PAGES counter in
set_migratetype_isolate()/unset_migratetype_isolate() and removing counter
adjustment for isolated pages from free_one_page() and split_free_page().

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 16 insertions, 5 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3f18a14effb8..d259cc2b69c1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -691,7 +691,8 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
         zone->pages_scanned = 0;
 
         __free_one_page(page, zone, order, migratetype);
-        __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
+        if (unlikely(migratetype != MIGRATE_ISOLATE))
+                __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
         spin_unlock(&zone->lock);
 }
 
@@ -1392,6 +1393,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
         unsigned int order;
         unsigned long watermark;
         struct zone *zone;
+        int mt;
 
         BUG_ON(!PageBuddy(page));
 
@@ -1407,7 +1409,10 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
         list_del(&page->lru);
         zone->free_area[order].nr_free--;
         rmv_page_order(page);
-        __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
+
+        mt = get_pageblock_migratetype(page);
+        if (unlikely(mt != MIGRATE_ISOLATE))
+                __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
 
         if (alloc_order != order)
                 expand(zone, page, alloc_order, order,
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 247d1f175739..3ca1716471bc 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -76,8 +76,12 @@ int set_migratetype_isolate(struct page *page)
 
 out:
         if (!ret) {
+                unsigned long nr_pages;
+
                 set_pageblock_isolate(page);
-                move_freepages_block(zone, page, MIGRATE_ISOLATE);
+                nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
+
+                __mod_zone_page_state(zone, NR_FREE_PAGES, -nr_pages);
         }
 
         spin_unlock_irqrestore(&zone->lock, flags);
@@ -89,12 +93,14 @@ out:
 void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 {
         struct zone *zone;
-        unsigned long flags;
+        unsigned long flags, nr_pages;
+
         zone = page_zone(page);
         spin_lock_irqsave(&zone->lock, flags);
         if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
                 goto out;
-        move_freepages_block(zone, page, migratetype);
+        nr_pages = move_freepages_block(zone, page, migratetype);
+        __mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages);
         restore_pageblock_isolate(page, migratetype);
 out:
         spin_unlock_irqrestore(&zone->lock, flags);