From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2157C43444 for ; Thu, 3 Jan 2019 10:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF3D021019 for ; Thu, 3 Jan 2019 10:13:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546510385; bh=q2nxlgDS4NAZROZjCEKEp4Lw1T0Pk6dE1bfU9gHrlnM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=SqZCQuOkon/V2siyaM/MUSsWEkj/KeoDXCOMVugWl47DsfsVvWkbuJ7Me0XRvEfjG LlZ4PfLDZvg78lwbmc+LyggndXRW+zizZxNYNCTTWKP3lldG2tjiFFKAXQPmeFO5mG 0RdYIKfxLicPzukZ2rx2arG73Yy3uSHi4JTjfLOg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730795AbfACKNE (ORCPT ); Thu, 3 Jan 2019 05:13:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:49116 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728530AbfACKNE (ORCPT ); Thu, 3 Jan 2019 05:13:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8136DAD4B; Thu, 3 Jan 2019 10:13:02 +0000 (UTC) Date: Thu, 3 Jan 2019 11:13:02 +0100 From: Michal Hocko To: Yang Shi Cc: hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] doc: memcontrol: fix the obsolete content about force empty Message-ID: <20190103101302.GI31793@dhcp22.suse.cz> References: <1546459533-36247-1-git-send-email-yang.shi@linux.alibaba.com> <1546459533-36247-2-git-send-email-yang.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546459533-36247-2-git-send-email-yang.shi@linux.alibaba.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 03-01-19 04:05:31, Yang Shi wrote: > We don't do page cache reparent anymore when offlining memcg, so update > force empty related content accordingly. > > Cc: Michal Hocko > Cc: Johannes Weiner > Signed-off-by: Yang Shi Thanks for the clean up. Acked-by: Michal Hocko > --- > Documentation/cgroup-v1/memory.txt | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt > index 3682e99..8e2cb1d 100644 > --- a/Documentation/cgroup-v1/memory.txt > +++ b/Documentation/cgroup-v1/memory.txt > @@ -70,7 +70,7 @@ Brief summary of control files. > memory.soft_limit_in_bytes # set/show soft limit of memory usage > memory.stat # show various statistics > memory.use_hierarchy # set/show hierarchical account enabled > - memory.force_empty # trigger forced move charge to parent > + memory.force_empty # trigger forced page reclaim > memory.pressure_level # set memory pressure notifications > memory.swappiness # set/show swappiness parameter of vmscan > (See sysctl's vm.swappiness) > @@ -459,8 +459,9 @@ About use_hierarchy, see Section 6. > the cgroup will be reclaimed and as many pages reclaimed as possible. > > The typical use case for this interface is before calling rmdir(). > - Because rmdir() moves all pages to parent, some out-of-use page caches can be > - moved to the parent. If you want to avoid that, force_empty will be useful. > + Though rmdir() offlines memcg, but the memcg may still stay there due to > + charged file caches. Some out-of-use page caches may keep charged until > + memory pressure happens. If you want to avoid that, force_empty will be useful. > > Also, note that when memory.kmem.limit_in_bytes is set the charges due to > kernel pages will still be seen. This is not considered a failure and the > -- > 1.8.3.1 > -- Michal Hocko SUSE Labs