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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no 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 F3D76C31E40 for ; Thu, 15 Aug 2019 04:53:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDB5E208C2 for ; Thu, 15 Aug 2019 04:53:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729853AbfHOExk (ORCPT ); Thu, 15 Aug 2019 00:53:40 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:41281 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725839AbfHOExj (ORCPT ); Thu, 15 Aug 2019 00:53:39 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R581e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07487;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0TZWJOlV_1565844812; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TZWJOlV_1565844812) by smtp.aliyun-inc.com(127.0.0.1); Thu, 15 Aug 2019 12:53:36 +0800 Subject: Re: [RESEND PATCH 1/2 -mm] mm: account lazy free pages separately To: Vlastimil Babka , Michal Hocko Cc: kirill.shutemov@linux.intel.com, hannes@cmpxchg.org, rientjes@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Linux API References: <1565308665-24747-1-git-send-email-yang.shi@linux.alibaba.com> <20190809083216.GM18351@dhcp22.suse.cz> <1a3c4185-c7ab-8d6f-8191-77dce02025a7@linux.alibaba.com> <20190809180238.GS18351@dhcp22.suse.cz> <79c90f6b-fcac-02e1-015a-0eaa4eafdf7d@linux.alibaba.com> <564a0860-94f1-6301-5527-5c2272931d8b@suse.cz> From: Yang Shi Message-ID: <96bd67c0-e53e-9802-a461-19ce47bba021@linux.alibaba.com> Date: Wed, 14 Aug 2019 21:53:30 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <564a0860-94f1-6301-5527-5c2272931d8b@suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/14/19 5:49 AM, Vlastimil Babka wrote: > On 8/9/19 8:26 PM, Yang Shi wrote: >> Here the new counter is introduced for patch 2/2 to account deferred >> split THPs into available memory since NR_ANON_THPS may contain >> non-deferred split THPs. >> >> I could use an internal counter for deferred split THPs, but if it is >> accounted by mod_node_page_state, why not just show it in /proc/meminfo? > The answer to "Why not" is that it becomes part of userspace API (btw this > patchset should have CC'd linux-api@ - please do for further iterations) and > even if the implementation detail of deferred splitting might change in the > future, we'll basically have to keep the counter (even with 0 value) in > /proc/meminfo forever. > > Also, quite recently we have added the following counter: > > KReclaimable: Kernel allocations that the kernel will attempt to reclaim > under memory pressure. Includes SReclaimable (below), and other > direct allocations with a shrinker. > > Although THP allocations are not exactly "kernel allocations", once they are > unmapped, they are in fact kernel-only, so IMHO it wouldn't be a big stretch to > add the lazy THP pages there? Thanks a lot for the suggestion. I agree it may be a good fit. Hope "kernel allocations" not cause confusion. But, we can explain in the documentation. > >> Or we fix NR_ANON_THPS and show deferred split THPs in /proc/meminfo? >>