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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 A2ED8C38A30 for ; Wed, 22 Apr 2020 03:16:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8273B20747 for ; Wed, 22 Apr 2020 03:16:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726398AbgDVDP7 (ORCPT ); Tue, 21 Apr 2020 23:15:59 -0400 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:36846 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726228AbgDVDP7 (ORCPT ); Tue, 21 Apr 2020 23:15:59 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01422;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0TwHav-7_1587525353; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0TwHav-7_1587525353) by smtp.aliyun-inc.com(127.0.0.1); Wed, 22 Apr 2020 11:15:54 +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> From: Alex Shi Message-ID: <2721c508-9b32-d0e7-454d-386129bfda1b@linux.alibaba.com> Date: Wed, 22 Apr 2020 11:14:40 +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: <20200421143923.GC341682@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 2020/4/21 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. Also as to the RSS account name change, I don't know if it's good to polish them in docs. Thanks Alex diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 0ae4f564c2d6..1fd0878089fe 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. @@ -230,10 +230,10 @@ caller of swapoff rather than the users of shmem. 2.4 Swap Extension (CONFIG_MEMCG_SWAP) -------------------------------------- -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 swap is limited, following files are added. - memory.memsw.usage_in_bytes. - memory.memsw.limit_in_bytes. > From a semantics POV, nothing changes with this patch. The memsw limit > defaults to "max", so it doesn't exert any control per default. The > only difference is whether we maintain swap records or not. >