From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by kanga.kvack.org (Postfix) with ESMTP id 8EAD48E0002 for ; Thu, 17 Jan 2019 16:57:22 -0500 (EST) Received: by mail-qt1-f198.google.com with SMTP id z6so10408132qtj.21 for ; Thu, 17 Jan 2019 13:57:22 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id a123si6317145qkd.182.2019.01.17.13.57.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Jan 2019 13:57:21 -0800 (PST) From: Jeff Moyer Subject: Re: [PATCH 0/4] Allow persistent memory to be used like normal RAM References: <20190116181859.D1504459@viggo.jf.intel.com> <20190117164736.GC31543@localhost.localdomain> <20190117193403.GD31543@localhost.localdomain> Date: Thu, 17 Jan 2019 16:57:17 -0500 In-Reply-To: <20190117193403.GD31543@localhost.localdomain> (Keith Busch's message of "Thu, 17 Jan 2019 12:34:03 -0700") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Keith Busch Cc: Dave Hansen , thomas.lendacky@amd.com, fengguang.wu@intel.com, dave@sr71.net, linux-nvdimm@lists.01.org, tiwai@suse.de, zwisler@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, baiyaowei@cmss.chinamobile.com, ying.huang@intel.com, bhelgaas@google.com, akpm@linux-foundation.org, bp@suse.de Keith Busch writes: >> Keith, you seem to be implying that there are platforms that won't >> support memory mode. Do you also have some insight into how customers >> want to use this, beyond my speculation? It's really frustrating to see >> patch sets like this go by without any real use cases provided. > > Right, most NFIT reporting platforms today don't have memory mode, and > the kernel currently only supports the persistent DAX mode with these. > This series adds another option for those platforms. All NFIT reporting platforms today are shipping NVDIMM-Ns, where it makes absolutely no sense to use them as regular DRAM. I don't think that's a good argument to make. > I think numactl as you mentioned is the first consideration for how > customers may make use. Dave or Dan might have other use cases in mind. Well, it sure looks like this took a lot of work, so I thought there were known use cases or users asking for this functionality. Cheers, Jeff 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 autolearn=unavailable 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 D839DC43387 for ; Thu, 17 Jan 2019 21:57:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 727CC20859 for ; Thu, 17 Jan 2019 21:57:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 727CC20859 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CB32C8E000F; Thu, 17 Jan 2019 16:57:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C635B8E0002; Thu, 17 Jan 2019 16:57:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B525E8E000F; Thu, 17 Jan 2019 16:57:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by kanga.kvack.org (Postfix) with ESMTP id 8EAD48E0002 for ; Thu, 17 Jan 2019 16:57:22 -0500 (EST) Received: by mail-qt1-f198.google.com with SMTP id z6so10408132qtj.21 for ; Thu, 17 Jan 2019 13:57:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:references:date:in-reply-to:message-id:user-agent :mime-version; bh=yID1VjSwUJ3rwmXIhP+rRft52nSsW6OpmvtouVrsmbc=; b=cdDXqHiIsTCiweQWED/50kStf2xrnM4Ov3BoThLyjMdmOVpR0XPrPYpmiWEgow2Xlt bpsEI/dGGq/DuY90X8lvvy0PVXzQs2UaYlz5NOvUhDp78wfg9RnTCR1zLmQr2eLtrgmf CEeYJSypgKy5ye35/sSK4BBIVk+ZYASVfZE9JvmfljVT1j7D5vtD09xtCCjSmMpTlCLE idmBP0+rro95dzFa7ii6CakUlBgT3CVHprkarqywDS2nhPIS4n0rUALGPxPlasTAbSrb iNmeOzJHj8l3cCp3WJW7CNK/lJVl9jTli30h4kRMUlcbih+tEKxz2E+X37ipQgj4F8NG KKfw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: AJcUukeeBEzDH8K7RV/Yqhk1bJoaxbELjwHEln17K6iyQvRV5tei0U/X DixEDM38XckCdyDId/XW1YZSUJBnOZSbe6MHy6bCkOF8j/fMvwjIYWWkUktzK7ZOFxpNfS9vMnl VCNuTsTfl86BrQSp8CAxbP8OM9SWMq3bmLBLzL2exd3KpEEp5SgTWfXzPWtmBu9mPmg== X-Received: by 2002:ad4:5307:: with SMTP id y7mr13328269qvr.9.1547762242322; Thu, 17 Jan 2019 13:57:22 -0800 (PST) X-Google-Smtp-Source: ALg8bN60jnZobReSLENe5EhLQUZm0FAPZTquI66EQB0eawGLfvXNvpZYYsiQS/84fGHyJfUvFGkU X-Received: by 2002:ad4:5307:: with SMTP id y7mr13328239qvr.9.1547762241767; Thu, 17 Jan 2019 13:57:21 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547762241; cv=none; d=google.com; s=arc-20160816; b=OUSZVz1EnhDc6R0yVJ9CBHEw9pBjXDXAaf/Byq5q8HUtvU/mk4tw/ItLzk0ztkA4pz BPh/ms5Gz/AnulHjkXXxP1ffeklOZr5dW3j4jSi9JHqj1kyuF01JssepbaOvKX2/q1s9 gpR0/bJx8VJNOdyO94pTW2YqFnfMyDR7qEHmb9+oQLbm05oElADZVdrCoul7/5fYYGNE gNCoenKA48/3HkjeLRkWTPodO/zbBQZ09o9zz0nYjKcpNKgTfJxtXuNafw2sOc9wyjg3 noMCf+VLV90MS5IKwQwGYrLisiYs3T1SLfynqcUOE1WaG68CF3IUV/U3lITvQ4FdhUNC htKw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:message-id:in-reply-to:date:references :subject:cc:to:from; bh=yID1VjSwUJ3rwmXIhP+rRft52nSsW6OpmvtouVrsmbc=; b=kX+fB+i9JhV9CnuspqhdvAKpihMrsW0MYFZVpben3b7I+tX0aTyriawK4EMJ7SYTFp DnnfII9s5ZbCcMJCPIfoOuHGT4pg4r24ggUGpe4FwS8fK1cIkHCEM58ZfdzLuxs8sbI3 PBnlUGBWhoiBan3l05aJrxXO+MlsT/n26XOgOfAL+yJw44Jkk9NnWLs3grjsMHwRdTe1 xZ8bW8+w//c2vcwS2UvYR19/9h0fHGLDinO1SvpKEkVwfynsgo/oBsk75saX1ZkgpctS pRe0yz9cXE91GEhFLvtmVV2/JtYT7nwov6DgU/cFQB4m0KXsSUClc8w516o895YfbMMz qSaQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id a123si6317145qkd.182.2019.01.17.13.57.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Jan 2019 13:57:21 -0800 (PST) Received-SPF: pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A727AA7875; Thu, 17 Jan 2019 21:57:20 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BDA6061B6C; Thu, 17 Jan 2019 21:57:18 +0000 (UTC) From: Jeff Moyer To: Keith Busch Cc: Dave Hansen , thomas.lendacky@amd.com, fengguang.wu@intel.com, dave@sr71.net, linux-nvdimm@lists.01.org, tiwai@suse.de, zwisler@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, baiyaowei@cmss.chinamobile.com, ying.huang@intel.com, bhelgaas@google.com, akpm@linux-foundation.org, bp@suse.de Subject: Re: [PATCH 0/4] Allow persistent memory to be used like normal RAM References: <20190116181859.D1504459@viggo.jf.intel.com> <20190117164736.GC31543@localhost.localdomain> <20190117193403.GD31543@localhost.localdomain> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Thu, 17 Jan 2019 16:57:17 -0500 In-Reply-To: <20190117193403.GD31543@localhost.localdomain> (Keith Busch's message of "Thu, 17 Jan 2019 12:34:03 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 17 Jan 2019 21:57:21 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Message-ID: <20190117215717.FuuGcw_btVIeNzf95gs4WLztDQOV1JMcwjqINQBisvg@z> Keith Busch writes: >> Keith, you seem to be implying that there are platforms that won't >> support memory mode. Do you also have some insight into how customers >> want to use this, beyond my speculation? It's really frustrating to see >> patch sets like this go by without any real use cases provided. > > Right, most NFIT reporting platforms today don't have memory mode, and > the kernel currently only supports the persistent DAX mode with these. > This series adds another option for those platforms. All NFIT reporting platforms today are shipping NVDIMM-Ns, where it makes absolutely no sense to use them as regular DRAM. I don't think that's a good argument to make. > I think numactl as you mentioned is the first consideration for how > customers may make use. Dave or Dan might have other use cases in mind. Well, it sure looks like this took a lot of work, so I thought there were known use cases or users asking for this functionality. Cheers, Jeff