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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A6F8C19F2B for ; Thu, 4 Aug 2022 09:30:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A72088E0002; Thu, 4 Aug 2022 05:30:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A20CD8E0001; Thu, 4 Aug 2022 05:30:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 90FAB8E0002; Thu, 4 Aug 2022 05:30:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 826088E0001 for ; Thu, 4 Aug 2022 05:30:40 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 554CE1203A3 for ; Thu, 4 Aug 2022 09:30:40 +0000 (UTC) X-FDA: 79761390240.11.EA2FD7C Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf19.hostedemail.com (Postfix) with ESMTP id C28BC1A00FC for ; Thu, 4 Aug 2022 09:30:38 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R811e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VLMBxaE_1659605434; Received: from 30.240.99.20(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0VLMBxaE_1659605434) by smtp.aliyun-inc.com; Thu, 04 Aug 2022 17:30:35 +0800 Message-ID: Date: Thu, 4 Aug 2022 17:30:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.0.3 Subject: Re: [RFC PATCH V4 1/1] mm: add last level page table numa info to /proc/pid/numa_pgtable To: David Hildenbrand , willy@infradead.org Cc: akpm@linux-foundation.org, adobriyan@gmail.com, keescook@chromium.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220801121727.76186-1-xhao@linux.alibaba.com> <20220801121727.76186-2-xhao@linux.alibaba.com> <0c1f9e76-9b1d-7069-bb09-c18e4f19f0c4@redhat.com> From: haoxin In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659605440; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3p+U4q/PUnw1+jVkVCR0JZXgrjjGj0HVo+aRPFkiTJE=; b=eJGqGgvGNgmt3J0bseXecPg3cW+YM7UWxt4iwWVihPE3WuRSmqU1UG4CepiBszCBbhcSWu SM5of7X8+fmkLWs3I8n28adUvqmEQVHPWvLpFaByVd175dHmI5yjz1X5oQqHck7VnjvfFX tJGMMy3CU9DmPr7uhD/pVk3eZBG5tyA= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of xhao@linux.alibaba.com designates 115.124.30.45 as permitted sender) smtp.mailfrom=xhao@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659605440; a=rsa-sha256; cv=none; b=v5aBNi/vhpQ47Cd7K34/HBMblFApYbOxmpro6o4JU3oqK8peRhHc3rxC7jL+c3a2BRCLIA X51hFjRocntfKCsO/F4Y9tfg4nhOtNhtxCumWyJOYQsPysr3Gcir35EwkfAsR2nmeQAE1Z va6fOi79xvt31fjcZSHEfLDFtOA3fjA= Authentication-Results: imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of xhao@linux.alibaba.com designates 115.124.30.45 as permitted sender) smtp.mailfrom=xhao@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: C28BC1A00FC X-Stat-Signature: cso7m1qc7adpib3riufhpz5sgpkqp38p X-Rspam-User: X-HE-Tag: 1659605438-583452 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: 在 2022/8/4 下午4:12, David Hildenbrand 写道: > On 04.08.22 10:04, haoxin wrote: >> 在 2022/8/1 下午9:28, David Hildenbrand 写道: >>> On 01.08.22 14:17, Xin Hao wrote: >>>> In many data center servers, the shared memory architectures is >>>> Non-Uniform Memory Access (NUMA), remote numa node data access >>>> often brings a high latency problem, but what we are easy to ignore >>>> is that the page table remote numa access, It can also leads to a >>>> performance degradation. >>> Let me try rewriting: >>> >>> " >>> Many data center servers employ Non-Uniform Memory Access (NUMA) >>> architectures. Remote numa memory access results in high latency. While >>> memory placement is one issue, sub-optimal page table placement can also >>> result in surprise performance degradation. >>> " >> Thanks,  it reads more clearly. >> >>>> So there add a new interface in /proc, This will help developers to >>>> get more info about performance issues if they are caused by cross-NUMA. >>> Why do we only care about "last level page table", why not about the others? >>> >>> IMHO, we could emit something like "0, 1, 3, 0" instead for a given user >>> space address, showing the NUMA node the page table belongs to from >>> highest to lowest page table level. >> I have planned to implement the PTE page table in this version first, >> and then support other page tables in the next patch later. > If there are plans, let's do it all at once, to get a good and single > interface to expose that information. Ok, thanks for your suggestion, I will implement it in the next version. >