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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65D3EC433F5 for ; Thu, 12 May 2022 07:03:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350649AbiELHDu (ORCPT ); Thu, 12 May 2022 03:03:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229934AbiELHDq (ORCPT ); Thu, 12 May 2022 03:03:46 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 555B457B12 for ; Thu, 12 May 2022 00:03:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652339025; x=1683875025; h=message-id:subject:from:to:date:in-reply-to:references: mime-version:content-transfer-encoding; bh=2BoPkenWCDtGr5uisyAJ+mBH2Rf2kRq/FNVqeUodPQc=; b=ZpgMFcEVxMlVjm1Ez1YSVa3LQaLy/3RbjD0u6zcOr5aQNwmvIgjEp1qj uz9sr2RKdKnsT5dJVeuUUUfNUREeQHRX86dQMbVHfGZpZTD7amyMrVaj4 87hfy4Qe2y2czrjP2Ga8DOiWWeHUFRwWTry843//VqAAKo15RZEHUCzD+ doW4U3RfudPZgqUYRhN8HW2ILHZRJyvY72Pc4AKIzVrdF3VxdVWZl78Se B1drLnpozpniYCXABYtw1C5ILqAtUasi/ssbDXQfecA5AoxXtmPB0pYIJ Sk7+YeAQPANuVbesy8TwGNaHIyeXOjXZmca6Aa+J1ret2hOedJ2oLOHMV A==; X-IronPort-AV: E=McAfee;i="6400,9594,10344"; a="267500389" X-IronPort-AV: E=Sophos;i="5.91,218,1647327600"; d="scan'208";a="267500389" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 May 2022 00:03:45 -0700 X-IronPort-AV: E=Sophos;i="5.91,218,1647327600"; d="scan'208";a="697915194" Received: from ruonanwa-mobl.ccr.corp.intel.com ([10.254.212.157]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 May 2022 00:03:39 -0700 Message-ID: <56b41ce6922ed5f640d9bd46a603fa27576532a9.camel@intel.com> Subject: Re: RFC: Memory Tiering Kernel Interfaces (v2) From: "ying.huang@intel.com" To: Wei Xu , Andrew Morton , Greg Thelen , "Aneesh Kumar K.V" , Yang Shi , Linux Kernel Mailing List , Jagdish Gediya , Michal Hocko , Tim C Chen , Dave Hansen , Alistair Popple , Baolin Wang , Feng Tang , Jonathan Cameron , Davidlohr Bueso , Dan Williams , David Rientjes , Linux MM , Brice Goglin , Hesham Almatary Date: Thu, 12 May 2022 15:03:36 +0800 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2022-05-11 at 23:22 -0700, Wei Xu wrote: > Sysfs Interfaces > ================ > > * /sys/devices/system/memtier/memtierN/nodelist > >   where N = 0, 1, 2 (the kernel supports only 3 tiers for now). > >   Format: node_list > >   Read-only. When read, list the memory nodes in the specified tier. > >   Tier 0 is the highest tier, while tier 2 is the lowest tier. > >   The absolute value of a tier id number has no specific meaning. >   What matters is the relative order of the tier id numbers. > >   When a memory tier has no nodes, the kernel can hide its memtier >   sysfs files. > > * /sys/devices/system/node/nodeN/memtier > >   where N = 0, 1, ... > >   Format: int or empty > >   When read, list the memory tier that the node belongs to. Its value >   is empty for a CPU-only NUMA node. > >   When written, the kernel moves the node into the specified memory >   tier if the move is allowed. The tier assignment of all other nodes >   are not affected. > >   Initially, we can make this interface read-only. It seems that "/sys/devices/system/node/nodeN/memtier" has all information we needed. Do we really need "/sys/devices/system/memtier/memtierN/nodelist"? That can be gotten via a simple shell command line, $ grep . /sys/devices/system/node/nodeN/memtier | sort -n -k 2 -t ':' Best Regards, Huang, Ying