From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id 39D138E0002 for ; Thu, 3 Jan 2019 05:13:04 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id o21so33668949edq.4 for ; Thu, 03 Jan 2019 02:13:04 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id j9si8761048edr.185.2019.01.03.02.13.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Jan 2019 02:13:02 -0800 (PST) Date: Thu, 3 Jan 2019 11:13:02 +0100 From: Michal Hocko 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> Sender: owner-linux-mm@kvack.org List-ID: To: Yang Shi Cc: hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, 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