From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f171.google.com (mail-lb0-f171.google.com [209.85.217.171]) by kanga.kvack.org (Postfix) with ESMTP id E90DE6B007B for ; Wed, 22 Oct 2014 11:49:19 -0400 (EDT) Received: by mail-lb0-f171.google.com with SMTP id z12so3102889lbi.30 for ; Wed, 22 Oct 2014 08:49:18 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id w3si601149law.79.2014.10.22.08.49.17 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 22 Oct 2014 08:49:18 -0700 (PDT) Date: Wed, 22 Oct 2014 17:49:18 +0200 From: Michal Hocko Subject: Re: [patch 3/4] mm: memcontrol: remove unnecessary PCG_MEM memory charge flag Message-ID: <20141022154918.GF30802@dhcp22.suse.cz> References: <1413818532-11042-1-git-send-email-hannes@cmpxchg.org> <1413818532-11042-4-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413818532-11042-4-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Hugh Dickins , Vladimir Davydov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org On Mon 20-10-14 11:22:11, 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: Michal Hocko > --- > 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); > > -- > 2.1.2 > -- Michal Hocko SUSE Labs -- 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