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 3B091C19F2B for ; Thu, 4 Aug 2022 08:12:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C02008E0002; Thu, 4 Aug 2022 04:12:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BB1788E0001; Thu, 4 Aug 2022 04:12:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A521E8E0002; Thu, 4 Aug 2022 04:12:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 91A068E0001 for ; Thu, 4 Aug 2022 04:12:05 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 664B91A083F for ; Thu, 4 Aug 2022 08:12:05 +0000 (UTC) X-FDA: 79761192210.18.9F0D669 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf08.hostedemail.com (Postfix) with ESMTP id BC0BA160120 for ; Thu, 4 Aug 2022 08:12:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659600724; h=from:from: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=aGdCtTL3UL2LGgp3SeT4qjaDXoDUVEPuKKGyzuwB8kA=; b=PTrs4u0iLHJHnpP+uAEZ8JYgUDydV0OMORVc+PYJ6ZWDLxAM1iaUTZiA19qv3aWfySU5SY jIe3Hyp+F00+vW1wQtvQu7viknatAJZ+qkQAMn5N8yeowXq39i67z0UOkM68mEA4xOkY/L 9fDlbSgU+VGql+OVCY2mGDI0LQ76lTo= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-255-s7vWetE_PheL3eB3yxLa4w-1; Thu, 04 Aug 2022 04:12:02 -0400 X-MC-Unique: s7vWetE_PheL3eB3yxLa4w-1 Received: by mail-wm1-f72.google.com with SMTP id p2-20020a05600c1d8200b003a3262d9c51so2295546wms.6 for ; Thu, 04 Aug 2022 01:12:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=aGdCtTL3UL2LGgp3SeT4qjaDXoDUVEPuKKGyzuwB8kA=; b=Mry+ofmbSRt+TxlPkMyshh9/k0BRR2t0OaSbw0ZztrYNh5a7dHA+1c1UUjvthpZRtp iFN3JMPiBFrGGIn31DbJuLycW6lWdFUHdUYYf8jVQDlBvo2GYaqYww73XpXmFEMB1cL+ NO/vEYZ0iMji8cM7/aT7Mrd1vQlV5MVW2NVFcJGBH8VczpH9K0M6t6eecgBd8ttNrjUj KldleXCFlh2+bLWT7IkZKrr0Pd6jbUpw+svoufpFRCb11WK+X9UNrx+SMMoRvtmtcmau cgxyJ8PBOvtVFjLWZMfGMdXyv4q0jLIEoZFl90S4NW9MuxH+Q2YlCXRYwCNnjyphp6lN COzQ== X-Gm-Message-State: ACgBeo2gd28Bl10c9alCQ7XBsvdJxuNOHdFh8aQQceRMDZBdztnQPO/R P+YuWvwWxl0Ry8Ec5gmnSJ/fTx7jhrLrBlmQo1qczDU+RNu6xKvvKTc5eLC7XGAHuiOAzI3dKFe ijfPy/mZBeoY= X-Received: by 2002:a5d:64ed:0:b0:220:703f:6dac with SMTP id g13-20020a5d64ed000000b00220703f6dacmr565038wri.28.1659600721738; Thu, 04 Aug 2022 01:12:01 -0700 (PDT) X-Google-Smtp-Source: AA6agR6HngA/rR4yDuzc0gS0/lhCN+Cjjv7Ttco7l7BobC6NlYILDIyPH468IAlqD9bqRIpNFyEfcg== X-Received: by 2002:a5d:64ed:0:b0:220:703f:6dac with SMTP id g13-20020a5d64ed000000b00220703f6dacmr565017wri.28.1659600721447; Thu, 04 Aug 2022 01:12:01 -0700 (PDT) Received: from ?IPV6:2003:cb:c706:8900:2c18:b992:1fa1:f88b? (p200300cbc70689002c18b9921fa1f88b.dip0.t-ipconnect.de. [2003:cb:c706:8900:2c18:b992:1fa1:f88b]) by smtp.gmail.com with ESMTPSA id s8-20020a05600c384800b003a503a64e5esm3517967wmr.15.2022.08.04.01.12.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 Aug 2022 01:12:00 -0700 (PDT) Message-ID: Date: Thu, 4 Aug 2022 10:12:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [RFC PATCH V4 1/1] mm: add last level page table numa info to /proc/pid/numa_pgtable To: haoxin , 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: David Hildenbrand Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659600725; a=rsa-sha256; cv=none; b=P5ujecLFiCpOAF+ydp7ViWiiVwtB+DAEfcBJPyIsoIUVZlG8T20uplcdE+6PLsNnmOiT2n domHbQZ3O+aRflkmSikP9fZRkO8ufQyyUCdS20I95bWswmOSMqDjCegysOr2YiH1BbouqC TRQpN/8NZYulfmQs2odaf9EdxrOSJrg= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=PTrs4u0i; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659600725; 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:dkim-signature; bh=aGdCtTL3UL2LGgp3SeT4qjaDXoDUVEPuKKGyzuwB8kA=; b=RxglyiC+o04DWBJ203fpAyVDUbWYXJq1B2YAn1WkgxZPK/GOV34b7OIUphWEpOSfZ2YCPf ICJC3ZzuB+54JgTzckgRSZLE1ioV+QCw3+h8Ll8oJk9HP+YhsRaXVgpV6Rui8YfjClcQ9U ++B6jqz6fgkFJCLIIYLmNhJI3aaFm0U= X-Stat-Signature: wcuasc17r5jcosyd68bw1d8p1hgz1s7g X-Rspamd-Queue-Id: BC0BA160120 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=PTrs4u0i; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1659600724-440446 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: 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. -- Thanks, David / dhildenb