@@ -2015,6 +2015,9 @@ static void drain_stock(struct memcg_stock_pcp *stock)
{
struct mem_cgroup *old = stock->cached;
+ if (!old)
+ return;
+
if (stock->nr_pages) {
page_counter_uncharge(&old->memory, stock->nr_pages);
if (do_memsw_account())
@@ -2022,6 +2025,8 @@ static void drain_stock(struct memcg_stock_pcp *stock)
css_put_many(&old->css, stock->nr_pages);
stock->nr_pages = 0;
}
+
+ css_put(&old->css);
stock->cached = NULL;
}
@@ -2057,6 +2062,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
stock = this_cpu_ptr(&memcg_stock);
if (stock->cached != memcg) { /* reset if necessary */
drain_stock(stock);
+ css_get(&memcg->css);
stock->cached = memcg;
}
stock->nr_pages += nr_pages;