From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 29E896B000C for ; Fri, 4 May 2018 07:12:16 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id y6-v6so13942981wrm.10 for ; Fri, 04 May 2018 04:12:16 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id d35-v6si1732688ede.353.2018.05.04.04.12.14 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 04 May 2018 04:12:15 -0700 (PDT) Date: Fri, 4 May 2018 13:12:11 +0200 From: Michal Hocko Subject: Re: [RFC PATCH] Add /proc//numa_vamaps for numa node information Message-ID: <20180504111211.GO4535@dhcp22.suse.cz> References: <1525240686-13335-1-git-send-email-prakash.sangappa@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: "prakash.sangappa" Cc: Christopher Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, drepper@gmail.com, rientjes@google.com On Thu 03-05-18 15:39:49, prakash.sangappa wrote: > > > On 05/03/2018 11:03 AM, Christopher Lameter wrote: > > On Tue, 1 May 2018, Prakash Sangappa wrote: > > > > > For analysis purpose it is useful to have numa node information > > > corresponding mapped address ranges of the process. Currently > > > /proc//numa_maps provides list of numa nodes from where pages are > > > allocated per VMA of the process. This is not useful if an user needs to > > > determine which numa node the mapped pages are allocated from for a > > > particular address range. It would have helped if the numa node information > > > presented in /proc//numa_maps was broken down by VA ranges showing the > > > exact numa node from where the pages have been allocated. > > Cant you write a small script that scans the information in numa_maps and > > then displays the total pages per NUMA node and then a list of which > > ranges have how many pages on a particular node? > > Don't think we can determine which numa node a given user process > address range has pages from, based on the existing 'numa_maps' file. yes we have. See move_pages... > > > reading this file will not be restricted(i.e requiring CAP_SYS_ADMIN). > > So a prime motivator here is security restricted access to numa_maps? > No it is the opposite. A regular user should be able to determine > numa node information. Well, that breaks the layout randomization, doesn't it? -- Michal Hocko SUSE Labs