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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 1DAFBC43441 for ; Mon, 26 Nov 2018 15:52:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E274420664 for ; Mon, 26 Nov 2018 15:52:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E274420664 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726895AbeK0Cqn (ORCPT ); Mon, 26 Nov 2018 21:46:43 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:40882 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726260AbeK0Cqn (ORCPT ); Mon, 26 Nov 2018 21:46:43 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 980F9351D; Mon, 26 Nov 2018 07:52:12 -0800 (PST) Received: from [10.1.196.73] (unknown [10.1.196.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3504F3F59C; Mon, 26 Nov 2018 07:52:11 -0800 (PST) Subject: Re: [PATCH 0/7] ACPI HMAT memory sysfs representation To: Dan Williams , Dave Hansen Cc: Keith Busch , Linux Kernel Mailing List , Linux ACPI , Linux MM , Greg KH , "Rafael J. Wysocki" References: <20181114224902.12082-1-keith.busch@intel.com> <1ed406b2-b85f-8e02-1df0-7c39aa21eca9@arm.com> <4ea6e80f-80ba-6992-8aa0-5c2d88996af7@intel.com> <9015e51a-3584-7bb2-cc5e-25b0ec8e5494@intel.com> From: Anshuman Khandual Message-ID: <4b9e30ea-aa8e-cfd7-230b-1d5b0a8837f4@arm.com> Date: Mon, 26 Nov 2018 21:22:13 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/24/2018 02:43 AM, Dan Williams wrote: > On Fri, Nov 23, 2018 at 11:21 AM Dave Hansen wrote: >> >> On 11/22/18 10:42 PM, Anshuman Khandual wrote: >>> Are we willing to go in the direction for inclusion of a new system >>> call, subset of it appears on sysfs etc ? My primary concern is not >>> how the attribute information appears on the sysfs but lack of it's >>> completeness. >> >> A new system call makes total sense to me. I have the same concern >> about the completeness of what's exposed in sysfs, I just don't see a >> _route_ to completeness with sysfs itself. Thus, the minimalist >> approach as a first step. > > Outside of platform-firmware-id to Linux-numa-node-id what other > userspace API infrastructure does the kernel need to provide? It seems > userspace enumeration of memory attributes is fully enabled once the > firmware-to-Linux identification is established. Which is true if the user space is required to probe the memory attribute values for the platform-firmware-id from the platform and then request required memory from corresponding Linux-numa-node-id via standard mm interfaces like mbind(). But in this patch series we are not mapping platform-firmware-id to Linux-numa-node-id. We are exporting properties applicable to Linux nodes (Linux-numa-node-id). Even if platform-firmware-id to Linux-numa-node-id is required it can be done through a new file like the following. Applications can just take the platform_id node and query platform about it's properties. /sys/devices/system/node/nodeX/platform_id This above interface would have been okay as its just an extension of the existing node information on sysfs. But thats not the case with this proposal.