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 07031C38A30 for ; Wed, 22 Apr 2020 03:16:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6293020722 for ; Wed, 22 Apr 2020 03:16:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6293020722 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 022278E0005; Tue, 21 Apr 2020 23:16:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F13CF8E0003; Tue, 21 Apr 2020 23:16:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E293A8E0005; Tue, 21 Apr 2020 23:16:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0142.hostedemail.com [216.40.44.142]) by kanga.kvack.org (Postfix) with ESMTP id C86A48E0003 for ; Tue, 21 Apr 2020 23:16:02 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 8F109824556B for ; Wed, 22 Apr 2020 03:16:02 +0000 (UTC) X-FDA: 76734026964.08.lock05_34a0ba1feb460 X-HE-Tag: lock05_34a0ba1feb460 X-Filterd-Recvd-Size: 4446 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Apr 2020 03:16:01 +0000 (UTC) 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: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: =E5=9C=A8 2020/4/21 =E4=B8=8B=E5=8D=8810:39, Johannes Weiner =E5=86=99=E9= =81=93: > Hi Alex, >=20 > thanks for your quick review so far, I'll add the tags to the patches. >=20 > On Tue, Apr 21, 2020 at 05:27:30PM +0800, Alex Shi wrote: >> >> >> =E5=9C=A8 2020/4/21 =E4=B8=8A=E5=8D=886:11, Johannes Weiner =E5=86=99=E9= =81=93: >>> The swapaccount=3D0 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? >=20 > Can you elaborate what you think is missing and where you would like > to see it documented? >=20 Maybe the following doc change is better after whole patchset?=20 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 poli= sh them in docs. Thanks Alex diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentati= on/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 ful= ly unmapped (by kswapd), they may exist as SwapCache in the system until th= ey 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 tas= k -causing page fault. So, we avoid accounting at swap-in I/O. +Since page's memcg recorded into swap whatever memsw enabled, the page w= ill +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 i= s -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. >=20