Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752248AbaKDIh0 (ORCPT ); Tue, 4 Nov 2014 03:37:26 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:51916 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbaKDIhZ (ORCPT ); Tue, 4 Nov 2014 03:37:25 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <54589017.9060604@jp.fujitsu.com> Date: Tue, 4 Nov 2014 17:36:39 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Johannes Weiner , Andrew Morton CC: Michal Hocko , Vladimir Davydov , Tejun Heo , David Miller , , , Subject: Re: [patch 1/3] mm: embed the memcg pointer directly into struct page References: <1414898156-4741-1-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1414898156-4741-1-git-send-email-hannes@cmpxchg.org> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit X-SecurityPolicyCheck-GC: OK by FENCE-Mail Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2014/11/02 12:15), Johannes Weiner wrote: > Memory cgroups used to have 5 per-page pointers. To allow users to > disable that amount of overhead during runtime, those pointers were > allocated in a separate array, with a translation layer between them > and struct page. > > There is now only one page pointer remaining: the memcg pointer, that > indicates which cgroup the page is associated with when charged. The > complexity of runtime allocation and the runtime translation overhead > is no longer justified to save that *potential* 0.19% of memory. With > CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding > after the page->private member and doesn't even increase struct page, > and then this patch actually saves space. Remaining users that care > can still compile their kernels without CONFIG_MEMCG. > > text data bss dec hex filename > 8828345 1725264 983040 11536649 b00909 vmlinux.old > 8827425 1725264 966656 11519345 afc571 vmlinux.new > > Signed-off-by: Johannes Weiner > --- > include/linux/memcontrol.h | 6 +- > include/linux/mm_types.h | 5 + > include/linux/mmzone.h | 12 -- > include/linux/page_cgroup.h | 53 -------- > init/main.c | 7 - > mm/memcontrol.c | 124 +++++------------ > mm/page_alloc.c | 2 - > mm/page_cgroup.c | 319 -------------------------------------------- > 8 files changed, 41 insertions(+), 487 deletions(-) > Great! Acked-by: KAMEZAWA Hiroyuki BTW, init/Kconfig comments shouldn't be updated ? (I'm sorry if it has been updated since your latest fix.) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/