From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) by kanga.kvack.org (Postfix) with ESMTP id 167A08E0002 for ; Thu, 17 Jan 2019 11:51:10 -0500 (EST) Received: by mail-oi1-f200.google.com with SMTP id d7so3623639oif.5 for ; Thu, 17 Jan 2019 08:51:10 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id z79sor944928oia.97.2019.01.17.08.51.08 for (Google Transport Security); Thu, 17 Jan 2019 08:51:08 -0800 (PST) MIME-Version: 1.0 References: <20190116181859.D1504459@viggo.jf.intel.com> In-Reply-To: From: Dan Williams Date: Thu, 17 Jan 2019 08:50:57 -0800 Message-ID: Subject: Re: [PATCH 0/4] Allow persistent memory to be used like normal RAM Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Jeff Moyer Cc: Dave Hansen , Tom Lendacky , Fengguang Wu , Dave Hansen , linux-nvdimm , Takashi Iwai , Ross Zwisler , Linux Kernel Mailing List , Linux MM , Michal Hocko , Yaowei Bai , "Huang, Ying" , Bjorn Helgaas , Andrew Morton , Borislav Petkov On Thu, Jan 17, 2019 at 8:29 AM Jeff Moyer wrote: > > Dave Hansen writes: > > > 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! > > So, isn't that what memory mode is for? > https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/ That's a hardware cache that privately manages DRAM in front of PMEM. It benefits from some help from software [1]. > Why do we need this code in the kernel? This goes further and enables software managed allocation decisions with the full DRAM + PMEM address space. [1]: https://lore.kernel.org/lkml/154767945660.1983228.12167020940431682725.stgit@dwillia2-desk3.amr.corp.intel.com/ 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=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,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 170CAC43387 for ; Thu, 17 Jan 2019 16:51:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BF5AF205C9 for ; Thu, 17 Jan 2019 16:51:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="XDmMmTRI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF5AF205C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5AA358E0008; Thu, 17 Jan 2019 11:51:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 557D78E0002; Thu, 17 Jan 2019 11:51:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 45AA58E0008; Thu, 17 Jan 2019 11:51:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) by kanga.kvack.org (Postfix) with ESMTP id 167A08E0002 for ; Thu, 17 Jan 2019 11:51:10 -0500 (EST) Received: by mail-oi1-f200.google.com with SMTP id d7so3623639oif.5 for ; Thu, 17 Jan 2019 08:51:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=eeqNNNSjGfrb/VOAvSUOR6b42db+Jqg9XHBp+kCWRWk=; b=VrOdZnL7IZ2NYf3FQtdQapwE/6V+jRt1AJM/bVuh8Ow4G7bisV5SDAARHlJy+YZOvq RaUBJuUT1rAh+NKFKXM7mwNPhBtitS9usLFCw7Y8yIqwMVT6vUxCcOHAKY00Xygx3CYk 3eeC1Q1FJR8+YrixVqYpVDYKYYhsvYDfEPSBj1xnyYeEoHeQloN9f9d5etZ3uzP+A0nk s3B43vUQROt01wOgSGWHQrwUyZ0GwWDNqrNtXb66oPPzAbOsrbkycKrWMZ4RZG4yL0Fq sYdsLSCIkUdgdLveCnxqPpfSAAyjVDrIati08Vl5PCHrE5J+NwJWXfnWF7+2QuPCzB0P rlYg== X-Gm-Message-State: AJcUukczwn3isGOfSfNzDyIw8dLnOMQnILSF069FWEWmXGcH1IoEqtZI KExeNnPTsymCRIjkrrJd9FvfKZ7piF4bbzSxItuGFqFIUW5f/3Z4hxYkSs5lsBk7wZZ+QSzSA5F EITSl6yqVjqU0k7OqnwkwVYTFWioPbzWMV8B3TJTB8XBGCNlHdq1KXJlDfoluKdn8YSv4bMfAJS LlGYvB6/myPg233D5RTvUJndNncrSV7AmP7Wr+VBWf1a8Z6a1DuMun3m9iSqYUEy9h5B2OSpTYH 3el7BcrD0BW0X0G3id5occ4fblhap/q+sW+NGpvJIH2c8K/+xShZpyQR055KW4CapGT8lyc4DvX 4j1sqBIXOQOGK/IUWsZvQT8cydXc2M7YY5COiYTouFpKK2zVCB0f9i3gJ15t1sQRe5LMwwzy/ry r X-Received: by 2002:a9d:6191:: with SMTP id g17mr9474511otk.56.1547743869617; Thu, 17 Jan 2019 08:51:09 -0800 (PST) X-Received: by 2002:a9d:6191:: with SMTP id g17mr9474481otk.56.1547743868783; Thu, 17 Jan 2019 08:51:08 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547743868; cv=none; d=google.com; s=arc-20160816; b=tuYKd7PFSj1q+jfF5n6pe32f9nkWmGJkT/NIf08wF8yhJlyDXhO1NaFgxtj0m0JOal nB3fFLpHbIgbwjUWT3+E2O3+lzELQfSh0mIbvCGDVrjLupTxOGE4gIXPX1xmPBB/+bDi wVcoQiXqSYQ33O67sps0teMp1GNOWmzRLhHCqt2lp4VQqjkvZlbkpB2FyAqx/zPREwjG YzoXirRmN7i1Lwt5+E92RbdcH37H+uLM6osIMd2SBbtwI3DRPlbpcAXwfe0UoY8x/lBH ZLhtZqTstW4He0uW7BlUo2cX79hU5i3mXLNGgsKp4FmTDF5Qrfl43RblV0PrkWPIPEUg kT5g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=eeqNNNSjGfrb/VOAvSUOR6b42db+Jqg9XHBp+kCWRWk=; b=WO/EzcNQwBYWznT838a1049/XcYVRjZBFm20ZeCJon9cgDtByWwxBTdh86IOCe4Z5r eeDZrPaO1oRoZXFN5RWFPzYMS6l1yOesyhJfVu4UC7c+ra/iT/OY5ezXY85VJYyTbYLP R+T/nu8MubwJKorw9AD/h79tyYNTctueSYWAQ0k09/slOFU1IUV5RpOuTmvaAM+jSjEh bfokUFvafukJpTDEPOmlZmfiHPtgJ+n8yuOJ/auZTYUmbw/zdtQX8Jq/j7TlFoIch3Ts qpFP4+6n7WjvCSti2nqnt930JlwAA3RIKcoLI4CeHCbdAAlfnpGkrpH104ssMn/E1+4Z lk8g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=XDmMmTRI; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id z79sor944928oia.97.2019.01.17.08.51.08 for (Google Transport Security); Thu, 17 Jan 2019 08:51:08 -0800 (PST) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=XDmMmTRI; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=eeqNNNSjGfrb/VOAvSUOR6b42db+Jqg9XHBp+kCWRWk=; b=XDmMmTRIBB5vKWP6TrUwQCEHemONZ8D/s0D83Xpx/UVBf9cANGrt0DX50SHJ9AGymu HGb+gf7w0IPrP41Y1j69q32oQnM1pvz89kwP3E/1/8xqNps7J5ibJPJ1dEso3eGhxQSD uZmCIpOfTK8l9dfeWt+Lryevm4UKRmUTz7h97P7SlCQD6vinUE2fUhhgVng/6w739Zfp Va3bxvf1ta0DfOAnb/GD6tnWwXaj8JFYUtcalUHgaeUCbhZmoeHYX8O7+zSRPw3lHhY4 WJXtIfp+GcvstcMA8ht+i0wW4eTQKWaDy3h/WWczw6uMXUP4+iOlnLScTvXwjiM6b/lF 64ZA== X-Google-Smtp-Source: ALg8bN5MbqsOaTEFby+rDYnDy2cAuiqqwg7op/akn51pGzRtGj2Cio9wpi3j/48ESGJDtvGyDnPXPzS9B6yq0EDd9sg= X-Received: by 2002:aca:d905:: with SMTP id q5mr5249519oig.0.1547743868290; Thu, 17 Jan 2019 08:51:08 -0800 (PST) MIME-Version: 1.0 References: <20190116181859.D1504459@viggo.jf.intel.com> In-Reply-To: From: Dan Williams Date: Thu, 17 Jan 2019 08:50:57 -0800 Message-ID: Subject: Re: [PATCH 0/4] Allow persistent memory to be used like normal RAM To: Jeff Moyer Cc: Dave Hansen , Tom Lendacky , Fengguang Wu , Dave Hansen , linux-nvdimm , Takashi Iwai , Ross Zwisler , Linux Kernel Mailing List , Linux MM , Michal Hocko , Yaowei Bai , "Huang, Ying" , Bjorn Helgaas , Andrew Morton , Borislav Petkov Content-Type: text/plain; charset="UTF-8" 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: <20190117165057.krLBtRleAucfc0Upgtg04W4MH0eeaE9pCVzREYxy1kQ@z> On Thu, Jan 17, 2019 at 8:29 AM Jeff Moyer wrote: > > Dave Hansen writes: > > > 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! > > So, isn't that what memory mode is for? > https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/ That's a hardware cache that privately manages DRAM in front of PMEM. It benefits from some help from software [1]. > Why do we need this code in the kernel? This goes further and enables software managed allocation decisions with the full DRAM + PMEM address space. [1]: https://lore.kernel.org/lkml/154767945660.1983228.12167020940431682725.stgit@dwillia2-desk3.amr.corp.intel.com/