From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752957AbaJTS7t (ORCPT ); Mon, 20 Oct 2014 14:59:49 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:43921 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751279AbaJTS7r (ORCPT ); Mon, 20 Oct 2014 14:59:47 -0400 Date: Mon, 20 Oct 2014 20:59:44 +0200 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Vladimir Davydov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch] mm: memcontrol: micro-optimize mem_cgroup_update_page_stat() Message-ID: <20141020185944.GC505@dhcp22.suse.cz> References: <1413818259-10913-1-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413818259-10913-1-git-send-email-hannes@cmpxchg.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 20-10-14 11:17:39, Johannes Weiner wrote: > 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 Acked-by: Michal Hocko mem_cgroup_split_huge_fixup is following the same pattern and might be folded into this one. I can send a separate patch if you prefer, though. --- diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3a203c7ec6c7..544e32292c7f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3167,7 +3167,7 @@ static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg) */ void mem_cgroup_split_huge_fixup(struct page *head) { - struct page_cgroup *head_pc = lookup_page_cgroup(head); + struct page_cgroup *head_pc; struct page_cgroup *pc; struct mem_cgroup *memcg; int i; @@ -3175,6 +3175,8 @@ void mem_cgroup_split_huge_fixup(struct page *head) if (mem_cgroup_disabled()) return; + head_pc = lookup_page_cgroup(head); + memcg = head_pc->mem_cgroup; for (i = 1; i < HPAGE_PMD_NR; i++) { pc = head_pc + i; -- Michal Hocko SUSE Labs