From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932393AbaJVBw3 (ORCPT ); Tue, 21 Oct 2014 21:52:29 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:40177 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932070AbaJVBw1 (ORCPT ); Tue, 21 Oct 2014 21:52:27 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <54470DC5.4050709@jp.fujitsu.com> Date: Wed, 22 Oct 2014 10:52:05 +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: Hugh Dickins , Michal Hocko , Vladimir Davydov , , , Subject: Re: [patch 3/4] mm: memcontrol: remove unnecessary PCG_MEM memory charge flag References: <1413818532-11042-1-git-send-email-hannes@cmpxchg.org> <1413818532-11042-4-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1413818532-11042-4-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 (2014/10/21 0:22), Johannes Weiner wrote: > PCG_MEM is a remnant from an earlier version of 0a31bc97c80c ("mm: > memcontrol: rewrite uncharge API"), used to tell whether migration > cleared a charge while leaving pc->mem_cgroup valid and PCG_USED set. > But in the final version, mem_cgroup_migrate() directly uncharges the > source page, rendering this distinction unnecessary. Remove it. > > Signed-off-by: Johannes Weiner Acked-by: KAMEZAWA Hiroyuki > --- > include/linux/page_cgroup.h | 1 - > mm/memcontrol.c | 4 +--- > 2 files changed, 1 insertion(+), 4 deletions(-) > > diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h > index da62ee2be28b..97536e685843 100644 > --- a/include/linux/page_cgroup.h > +++ b/include/linux/page_cgroup.h > @@ -4,7 +4,6 @@ > enum { > /* flags for mem_cgroup */ > PCG_USED = 0x01, /* This page is charged to a memcg */ > - PCG_MEM = 0x02, /* This page holds a memory charge */ > }; > > struct pglist_data; > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 9bab35fc3e9e..1d66ac49e702 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2606,7 +2606,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg, > * have the page locked > */ > pc->mem_cgroup = memcg; > - pc->flags = PCG_USED | PCG_MEM; > + pc->flags = PCG_USED; > > if (lrucare) > unlock_page_lru(page, isolated); > @@ -6177,8 +6177,6 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, > if (!PageCgroupUsed(pc)) > return; > > - VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage); > - > if (lrucare) > lock_page_lru(oldpage, &isolated); > >