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=-0.9 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 8B8DAC04EB9 for ; Mon, 3 Dec 2018 09:22:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56F4D2147C for ; Mon, 3 Dec 2018 09:22:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56F4D2147C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S1726032AbeLCJWk (ORCPT ); Mon, 3 Dec 2018 04:22:40 -0500 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:25800 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725888AbeLCJWk (ORCPT ); Mon, 3 Dec 2018 04:22:40 -0500 X-IronPort-AV: E=Sophos;i="5.56,310,1539640800"; d="scan'208";a="358424770" Received: from nat-inria-bordeaux-52-gw-01-bso.bordeaux.inria.fr (HELO [10.204.4.43]) ([194.199.1.52]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/AES128-SHA; 03 Dec 2018 10:22:25 +0100 Subject: Re: [PATCH 0/9] Allow persistent memory to be used like normal RAM To: Dave Hansen , linux-kernel@vger.kernel.org Cc: dan.j.williams@intel.com, dave.jiang@intel.com, zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, akpm@linux-foundation.org, mhocko@suse.com, linux-nvdimm@lists.01.org, linux-mm@kvack.org, ying.huang@intel.com, fengguang.wu@intel.com References: <20181022201317.8558C1D8@viggo.jf.intel.com> From: Brice Goglin Openpgp: preference=signencrypt Autocrypt: addr=brice.goglin@gmail.com; prefer-encrypt=mutual; keydata= mQINBFNg91oBEADMfOyfz9iilNPe1Yy3pheXLf5O/Vpr+gFJoXcjA80bMeSWBf4on8Mt5Fg/ jpVuNBhii0Zyq4Lip1I2ve+WQjfL3ixYQqvNRLgfw/FL0gNHSOe9dVFo0ol0lT+vu3AXOVmh AM4IrsOp2Tmt+w89Oyvu+xwHW54CJX3kXp4c7COz79A6OhbMEPQUreerTavSvYpH5pLY55WX qOSdjmlXD45yobQbMg9rFBy1BECrj4DJSpym/zJMFVnyC5yAq2RdPFRyvYfS0c491adD/iw9 eFZY1XWj+WqLSW8zEejdl78npWOucfin7eAKvov5Bqa1MLGS/2ojVMHXJN0qpStpKcueV5Px igX8i4O4pPT10xCXZ7R6KIGUe1FE0N7MLErLvBF6AjMyiFHix9rBG0pWADgCQUUFjc8YBKng nwIKl39uSpk5W5rXbZ9nF3Gp/uigTBNVvaLO4PIDw9J3svHQwCB31COsUWS1QhoLMIQPdUkk GarScanm8i37Ut9G+nB4nLeDRYpPIVBFXFD/DROIEfLqOXNbGwOjDd5RWuzA0TNzJSeOkH/0 qYr3gywjiE81zALO3UeDj8TaPAv3Dmu7SoI86Bl7qm6UOnSL7KQxZWuMTlU3BF3d+0Ly0qxv k1XRPrL58IyoHIgAVom0uUnLkRKHczdhGDpNzsQDJaO71EPp8QARAQABuQINBFNg91oBEADp 3vwjw8tQBnNfYJNJMs6AXC8PXB5uApT1pJ0fioaXvifPNL6gzsGtAF53aLeqB7UXuByHr8Bm sz7BvwA06XfXXdyLQP+8Oz3ZnUpw5inDIzLpRbUuAjI+IjUtguIKAkU1rZNdCXMOqEwCaomR itwaiX9H7yiDTKCUaqx8yAuAQWactWDdyFii2FA7IwVlD/GBqMWVweZsMfeWgPumKB3jyElm 1RpkzULrtKbu7MToMH2fmWqBtTkRptABkY7VEd8qENKJBZKJGiskFk6ylp8VzZdwbAtEDDTG K00Vg4PZGiIGbQo8mBqbc63DY+MdyUEksTTu2gTcqZMm/unQUJA8xB4JrTAyljo/peIt6lsQ a4+/eVolfKL1t1C3DY8f4wMoqnZORagnWA2oHsLsYKvcnqzA0QtYIIb1S1YatV+MNMFf3HuN 7xr/jWlfdt59quXiOHU3qxIzXJo/OfC3mwNW4zQWJkG233UOf6YErmrSaTIBTIWF8CxGY9iX PaJGNYSUa6R/VJS09EWeZgRz9Gk3h5AyDrdo5RFN9HNwOj41o0cjeLDF69092Lg5p5isuOqs rlPi5imHKcDtrXS7LacUI6H0c8onWoH9LuW99WznEtFgPJg++TAvf9M2x57Gzl+/nYTB5/Kp l1qdPPC91zUipiKbnF5f8bQpol0WC+ovmQARAQABiQIfBBgBAgAJBQJTYPdaAhsMAAoJEESR kPMjWr074+0P/iEcN27dx3oBTzoeGEBhZUVQRZ7w4A61H/vW8oO8IPkZv9kFr5pCfIonmHEb Blg6yfjeHXwF5SF2ywWRKkRsFHpaFWywxqk9HWXu8cGR1pFsrwC3EdossuVbEFNmhjHvcAo1 1nJ7JFzPTEnlPjE6OY9tEDwl+kp1WvyXqNk9bosaX8ivikhmhB477BA3Kv8uUE7UL6p7CBdq umaOFISi1we5PYE4P/6YcyhQ9Z2wH6ad2PpwAFNBwxSu+xCrVmaDskAwknf6UVPN3bt67sFA aVgotepx6SPhBuH4OSOxVHMDDLMu7W7pJjnSKzMcAyXmdjON05SzSaILwfceByvHAnvcFh2p XK9U4E/SyWZDJEcGRRt79akzZxls52stJK/2Tsr0vKtZVAwogiaKuSp+m6BRQcVVhTo/Kq3E 0tSnsTHFeIO6QFHKJCJv4FRE3Dmtz15lueihUBowsq9Hk+u3UiLoSmrMAZ6KgA4SQxB2p8/M 53kNJl92HHc9nc//aCQDi1R71NyhtSx+6PyivoBkuaKYs+S4pHmtsFE+5+pkUNROtm4ExLen 4N4OL6Kq85mWGf2f6hd+OWtn8we1mADjDtdnDHuv+3E3cacFJPP/wFV94ZhqvW4QcyBWcRNF A5roa7vcnu/MsCcBoheR0UdYsOnJoEpSZswvC/BGqJTkA2sf Message-ID: Date: Mon, 3 Dec 2018 10:22:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20181022201317.8558C1D8@viggo.jf.intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 22/10/2018 à 22:13, Dave Hansen a écrit : > Persistent memory is cool. But, currently, you have to rewrite > your applications to use it. Wouldn't it be cool if you could > just have it show up in your system like normal RAM and get to > it like a slow blob of memory? Well... have I got the patch > series for you! > > This series adds a new "driver" to which pmem devices can be > attached. Once attached, the memory "owned" by the device is > hot-added to the kernel and managed like any other memory. On > systems with an HMAT (a new ACPI table), each socket (roughly) > will have a separate NUMA node for its persistent memory so > this newly-added memory can be selected by its unique NUMA > node. Hello Dave What happens on systems without an HMAT? Does this new memory get merged into existing NUMA nodes? Also, do you plan to have a way for applications to find out which NUMA nodes are "real DRAM" while others are "pmem-backed"? (something like a new attribute in /sys/devices/system/node/nodeX/) Or should we use HMAT performance attributes for this? Brice