From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f42.google.com (mail-la0-f42.google.com [209.85.215.42]) by kanga.kvack.org (Postfix) with ESMTP id DA2CC6B006E for ; Mon, 20 Oct 2014 11:17:47 -0400 (EDT) Received: by mail-la0-f42.google.com with SMTP id gf13so4601219lab.29 for ; Mon, 20 Oct 2014 08:17:47 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id rs4si14815503lbb.12.2014.10.20.08.17.45 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Oct 2014 08:17:46 -0700 (PDT) From: Johannes Weiner Subject: [patch] mm: memcontrol: micro-optimize mem_cgroup_update_page_stat() Date: Mon, 20 Oct 2014 11:17:39 -0400 Message-Id: <1413818259-10913-1-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Michal Hocko , Vladimir Davydov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Do not look up the page_cgroup when the memory controller is runtime-disabled, but do assert that the locking protocol is followed under DEBUG_VM regardless. Also remove the unused flags variable. Signed-off-by: Johannes Weiner --- mm/memcontrol.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 76892eb89d26..bea3fddb3372 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2177,13 +2177,14 @@ void mem_cgroup_update_page_stat(struct page *page, enum mem_cgroup_stat_index idx, int val) { struct mem_cgroup *memcg; - struct page_cgroup *pc = lookup_page_cgroup(page); - unsigned long uninitialized_var(flags); + struct page_cgroup *pc; + + VM_BUG_ON(!rcu_read_lock_held()); if (mem_cgroup_disabled()) return; - VM_BUG_ON(!rcu_read_lock_held()); + pc = lookup_page_cgroup(page); memcg = pc->mem_cgroup; if (unlikely(!memcg || !PageCgroupUsed(pc))) return; -- 2.1.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org