Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp3254483imu; Fri, 18 Jan 2019 07:22:35 -0800 (PST) X-Google-Smtp-Source: ALg8bN5kNpfVySeuqvpbF2E93kipwgC0nozhkDra3cwCKo+XuATLs4yFYOliiIs2EO4k3eATThZd X-Received: by 2002:a63:70c:: with SMTP id 12mr17577793pgh.352.1547824955936; Fri, 18 Jan 2019 07:22:35 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547824955; cv=none; d=google.com; s=arc-20160816; b=ym2QbobGgbZhZ9QaHDtAhjdt2Y3HjgHlj2j04ZwoufYRYJ8SCGhBOSKIt8ItVlaPFx T94oQY5lwZPfVI47xpZtcf/I1mAuAqlZhTyfUfbSMLuaZyA1GoE8dEHrYVTDm9CedKyU eqojkPiKOSVvQKS9ZDkkAKWrdh/F7swTAf7Rk0wk4zuRf4zDUBWX8HsRehW9F0dba57D AmkyqBnyqKBIKENW/oJcxUYk6ABz9RGhPGfs2QMHIkTFE8JGyX4sMDAAPJXWmFIdQmfi d+sCMIKIOSTISdNE3Fl8pAmPQvakNF+YfW+2kcnLUFFgfOy/IybntOLFoQB14Qx2VRtQ /abw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:autocrypt:openpgp:from:references:cc:to:subject; bh=I5GPVH5lWgHtzPSF9bVd3GPhPTMh3q3zwEtwMrAokg0=; b=qN+wCilGFLyj9jV8tPHcW8OjSFaINMF+S8lN1p3psncXHsrQmoupQNT/V6GO98rPhI EbELBu97axEk/Q5XS07o8tQiIJcMChdKE0Ys7XARcUXiNdhilO+tuHT5BrTaW37D4kje 70S4tlVbVBDT4qpqW/bVcT1gT8E0uik+NoItrkVuIh6D4UgCVOD5pWViJlmHLJYXfKfa KnW9nleB+G1J34u/F7XnsJSlm2ICNl1hgQ4S/a7SxJRC1+rXLjfiXJeDjSNJ/CiaopTs KBQ1mfBmKVr9Ei9rXAtXgIjVJSvg+q37bakD6KOaHiefC3/W9zDaz93NSlFS+ES5Auvv rIIQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id l10si5001818pls.162.2019.01.18.07.22.16; Fri, 18 Jan 2019 07:22:35 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727688AbfARPUq (ORCPT + 99 others); Fri, 18 Jan 2019 10:20:46 -0500 Received: from mga11.intel.com ([192.55.52.93]:19275 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727020AbfARPUp (ORCPT ); Fri, 18 Jan 2019 10:20:45 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Jan 2019 07:20:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,491,1539673200"; d="scan'208";a="126883457" Received: from wstone-mobl.amr.corp.intel.com (HELO [10.251.10.184]) ([10.251.10.184]) by FMSMGA003.fm.intel.com with ESMTP; 18 Jan 2019 07:20:43 -0800 Subject: Re: [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM To: Yanmin Zhang , Dave Hansen , dave@sr71.net 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-kernel@vger.kernel.org, linux-mm@kvack.org, ying.huang@intel.com, fengguang.wu@intel.com, bp@suse.de, bhelgaas@google.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de References: <20190116181859.D1504459@viggo.jf.intel.com> <20190116181905.12E102B4@viggo.jf.intel.com> <5ef5d5e9-9d35-fb84-b69e-7456dcf4c241@linux.intel.com> <1e9377c6-11a0-3bbd-763d-d9347bd556cf@intel.com> <74c01a55-1a47-d649-a32a-ea597c24ab4a@linux.intel.com> From: Dave Hansen Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@intel.com; keydata= mQINBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABtEVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT6JAjgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lcuQINBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABiQIfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y Message-ID: <49681805-b521-71c9-23c0-9bb35d25ba58@intel.com> Date: Fri, 18 Jan 2019 07:20:43 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <74c01a55-1a47-d649-a32a-ea597c24ab4a@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/17/19 11:47 PM, Yanmin Zhang wrote: > a chance for kernel to allocate PMEM as DMA buffer. > Some super speed devices like 10Giga NIC, USB (SSIC connecting modem), > might not work well if DMA buffer is in PMEM as it's slower than DRAM. > > Should your patchset consider it? No, I don't think so. They can DMA to persistent memory whether this patch set exists or not. So, if the hardware falls over, that's a separate problem. If an app wants memory that performs in a particular way, then I would suggest those app find the NUMA nodes on the system that match their needs with these patches: > http://lkml.kernel.org/r/20190116175804.30196-1-keith.busch@intel.com and use the existing NUMA APIs to select that memory.