Merge branch 'master'

1 files changed, 24 insertions, 3 deletions

diff --git a/mm/swap.c b/mm/swap.c
index 76247424dea..e9ec06d845e 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -40,7 +40,7 @@ static void put_compound_page(struct page *page)
 	if (put_page_testzero(page)) {
 		void (*dtor)(struct page *page);
 
-		dtor = (void (*)(struct page *))page[1].mapping;
+		dtor = (void (*)(struct page *))page[1].lru.next;
 		(*dtor)(page);
 	}
 }
@@ -489,13 +489,34 @@ void percpu_counter_mod(struct percpu_counter *fbc, long amount)
 	if (count >= FBC_BATCH || count <= -FBC_BATCH) {
 		spin_lock(&fbc->lock);
 		fbc->count += count;
+		*pcount = 0;
 		spin_unlock(&fbc->lock);
-		count = 0;
+	} else {
+		*pcount = count;
 	}
-	*pcount = count;
 	put_cpu();
 }
 EXPORT_SYMBOL(percpu_counter_mod);
+
+/*
+ * Add up all the per-cpu counts, return the result.  This is a more accurate
+ * but much slower version of percpu_counter_read_positive()
+ */
+long percpu_counter_sum(struct percpu_counter *fbc)
+{
+	long ret;
+	int cpu;
+
+	spin_lock(&fbc->lock);
+	ret = fbc->count;
+	for_each_cpu(cpu) {
+		long *pcount = per_cpu_ptr(fbc->counters, cpu);
+		ret += *pcount;
+	}
+	spin_unlock(&fbc->lock);
+	return ret < 0 ? 0 : ret;
+}
+EXPORT_SYMBOL(percpu_counter_sum);
 #endif
 
 /*