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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 31F8BC54FCB for ; Wed, 22 Apr 2020 13:41:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 136532076E for ; Wed, 22 Apr 2020 13:41:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726847AbgDVNlr (ORCPT ); Wed, 22 Apr 2020 09:41:47 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:45232 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725839AbgDVNlq (ORCPT ); Wed, 22 Apr 2020 09:41:46 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0TwKjoiT_1587562901; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0TwKjoiT_1587562901) by smtp.aliyun-inc.com(127.0.0.1); Wed, 22 Apr 2020 21:41:42 +0800 Subject: Re: [PATCH 15/18] mm: memcontrol: make swap tracking an integral part of memory control To: Johannes Weiner Cc: Joonsoo Kim , Shakeel Butt , Hugh Dickins , Michal Hocko , "Kirill A. Shutemov" , Roman Gushchin , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com References: <20200420221126.341272-1-hannes@cmpxchg.org> <20200420221126.341272-16-hannes@cmpxchg.org> <20200421143923.GC341682@cmpxchg.org> <2721c508-9b32-d0e7-454d-386129bfda1b@linux.alibaba.com> <20200422133001.GE358439@cmpxchg.org> From: Alex Shi Message-ID: <66573da2-f863-bf6e-cc48-fb2540148d1d@linux.alibaba.com> Date: Wed, 22 Apr 2020 21:40:28 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200422133001.GE358439@cmpxchg.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/4/22 下午9:30, Johannes Weiner 写道: > On Wed, Apr 22, 2020 at 11:14:40AM +0800, Alex Shi wrote: >> >> >> 在 2020/4/21 下午10:39, Johannes Weiner 写道: >>> Hi Alex, >>> >>> thanks for your quick review so far, I'll add the tags to the patches. >>> >>> On Tue, Apr 21, 2020 at 05:27:30PM +0800, Alex Shi wrote: >>>> >>>> >>>> 在 2020/4/21 上午6:11, Johannes Weiner 写道: >>>>> The swapaccount=0 boot option will continue to exist, and it will >>>>> eliminate the page_counter overhead and hide the swap control files, >>>>> but it won't disable swap slot ownership tracking. >>>> >>>> May we add extra explanation for this change to user? and the default >>>> memsw limitations? >>> >>> Can you elaborate what you think is missing and where you would like >>> to see it documented? >>> >> Maybe the following doc change is better after whole patchset? >> Guess users would would happy to know details of this change. > > Thanks, I stole your patch and extended/tweaked it a little. Would you > mind providing your Signed-off-by:? My pleasure. :) Signed-off-by: Alex Shi > > From 589d3c1b505e6671b4a9b424436c9eda88a0b08c Mon Sep 17 00:00:00 2001 > From: Alex Shi > Date: Wed, 22 Apr 2020 11:14:40 +0800 > Subject: [PATCH] mm: memcontrol: document the new swap control behavior > > Signed-off-by: Johannes Weiner > --- > .../admin-guide/cgroup-v1/memory.rst | 19 +++++++------------ > 1 file changed, 7 insertions(+), 12 deletions(-) > > diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst > index 0ae4f564c2d6..12757e63b26c 100644 > --- a/Documentation/admin-guide/cgroup-v1/memory.rst > +++ b/Documentation/admin-guide/cgroup-v1/memory.rst > @@ -199,11 +199,11 @@ An RSS page is unaccounted when it's fully unmapped. A PageCache page is > unaccounted when it's removed from radix-tree. Even if RSS pages are fully > unmapped (by kswapd), they may exist as SwapCache in the system until they > are really freed. Such SwapCaches are also accounted. > -A swapped-in page is not accounted until it's mapped. > +A swapped-in page is accounted after adding into swapcache. > > Note: The kernel does swapin-readahead and reads multiple swaps at once. > -This means swapped-in pages may contain pages for other tasks than a task > -causing page fault. So, we avoid accounting at swap-in I/O. > +Since page's memcg recorded into swap whatever memsw enabled, the page will > +be accounted after swapin. > > At page migration, accounting information is kept. > > @@ -222,18 +222,13 @@ the cgroup that brought it in -- this will happen on memory pressure). > But see section 8.2: when moving a task to another cgroup, its pages may > be recharged to the new cgroup, if move_charge_at_immigrate has been chosen. > > -Exception: If CONFIG_MEMCG_SWAP is not used. > -When you do swapoff and make swapped-out pages of shmem(tmpfs) to > -be backed into memory in force, charges for pages are accounted against the > -caller of swapoff rather than the users of shmem. > - > -2.4 Swap Extension (CONFIG_MEMCG_SWAP) > +2.4 Swap Extension > -------------------------------------- > > -Swap Extension allows you to record charge for swap. A swapped-in page is > -charged back to original page allocator if possible. > +Swap usage is always recorded for each of cgroup. Swap Extension allows you to > +read and limit it. > > -When swap is accounted, following files are added. > +When CONFIG_SWAP is enabled, following files are added. > > - memory.memsw.usage_in_bytes. > - memory.memsw.limit_in_bytes. >