mm, memcg: save some atomic ops when flush is already true

Add 'else' to save some atomic ops in obj_stock_flush_required() when
flush is already true.  No functional change intended here.

Link: https://lkml.kernel.org/r/20210807082835.61281-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 80840e0..894a24d 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2246,7 +2246,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
                if (memcg && stock->nr_pages &&
                    mem_cgroup_is_descendant(memcg, root_memcg))
                        flush = true;
-               if (obj_stock_flush_required(stock, root_memcg))
+               else if (obj_stock_flush_required(stock, root_memcg))
                        flush = true;
                rcu_read_unlock();