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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED 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 3E3A4C10F06 for ; Tue, 12 Mar 2019 00:08:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B1772075C for ; Tue, 12 Mar 2019 00:08:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552349286; bh=MBBhdiZfWZ2ilnjglUlq5xOXlZEERkebtEGLShrSceo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=j9oVFLdchoAPZ2LO7JiVuFOm03bykmz5cMNY5tBpCN09pWG17uTXZ+dvObm9zoUox Te7yt8CgoxcnBmpmn/FACWaoD5QCJ0dp6elFD6ZiQQQnQ5G1a08KBdezdi42bQNlQS z8NibN4hdzfv1UpdBvg4JX19FBrphpa3xHYG1+y4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726485AbfCLAIE (ORCPT ); Mon, 11 Mar 2019 20:08:04 -0400 Received: from mail-lf1-f67.google.com ([209.85.167.67]:39211 "EHLO mail-lf1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725932AbfCLAID (ORCPT ); Mon, 11 Mar 2019 20:08:03 -0400 Received: by mail-lf1-f67.google.com with SMTP id m13so660453lfb.6 for ; Mon, 11 Mar 2019 17:08:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Qt694sGi2lwRRCAVHkTT7ndj+scdvDKwGl7sZfr8K8k=; b=A0yHjNKx5WvptfvDAlJCIScPZv5yWQVdV6SuSraSXLmHtTV6Ax0AesK3ins9D80g60 Ku3kCS5faTcIuBqylJyRTEgWvdj0jF1oK1H1QNGjebEf0GRRcM7bohsnDyUdK4KpY0dr qNth7eZOZNiQyNe0TsSFjfOMEJDmo08bqpyEg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Qt694sGi2lwRRCAVHkTT7ndj+scdvDKwGl7sZfr8K8k=; b=WYpBVpa3SL2w/pe+sg4Ka+dcuv/3j2g3SqsUNtxJf9EgYgjebUyOy1kPr7/TRnOjeo rE09UPiy7Gyv5JI00qaE/LdFfFTRoPNj0KnHV9s0qtW9ggJzZft1Gt6NQF/FnBNJNU/6 +aeppeE2aNRgL3WhCJ48APOzbk5L48Gao5clDatNrVZ1zA6/lHxnu8mCLXmw4WISp+7o bOWTzE37VGmnwTXDbEviGt3Z0dXLM+ioMgLbv47le3vMh/+pFp6S3cyRbyvFbdiWTH5M KOwd4ew5SuqFEVUHJjAexQ3yu//FFQCJ5pISniUo/sPDroJjLy4f7UOLCNRNlF1v7Jeh MjVg== X-Gm-Message-State: APjAAAWp1BHAK1MLdZW4ke1iXF775HcyUIzDuIgjt02Y8e1+xTgvOROP IpZudJ1B2V4pGBTd/3ur/w+N8jj6WAg= X-Google-Smtp-Source: APXvYqxBF6mSLdr72stqyidF4hjvLFOWFt6lPWlJ7X+EMjxaRe/6liheKpDRO0uWmqiflvSSgMgHxg== X-Received: by 2002:a19:9a8d:: with SMTP id c135mr18247873lfe.100.1552349280646; Mon, 11 Mar 2019 17:08:00 -0700 (PDT) Received: from mail-lj1-f178.google.com (mail-lj1-f178.google.com. [209.85.208.178]) by smtp.gmail.com with ESMTPSA id d23sm1296923lfc.11.2019.03.11.17.07.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Mar 2019 17:07:59 -0700 (PDT) Received: by mail-lj1-f178.google.com with SMTP id v16so649334ljg.13 for ; Mon, 11 Mar 2019 17:07:59 -0700 (PDT) X-Received: by 2002:a2e:8018:: with SMTP id j24mr17374435ljg.118.1552349279030; Mon, 11 Mar 2019 17:07:59 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Linus Torvalds Date: Mon, 11 Mar 2019 17:07:43 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [GIT PULL] device-dax for 5.1: PMEM as RAM To: Dan Williams Cc: Linux Kernel Mailing List , linux-nvdimm , Linux MM , Dave Hansen , "Luck, Tony" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 11, 2019 at 8:37 AM Dan Williams wrote: > > Another feature the userspace tooling can support for the PMEM as RAM > case is the ability to complete an Address Range Scrub of the range > before it is added to the core-mm. I.e at least ensure that previously > encountered poison is eliminated. Ok, so this at least makes sense as an argument to me. In the "PMEM as filesystem" part, the errors have long-term history, while in "PMEM as RAM" the memory may be physically the same thing, but it doesn't have the history and as such may not be prone to long-term errors the same way. So that validly argues that yes, when used as RAM, the likelihood for errors is much lower because they don't accumulate the same way. > The driver can also publish an > attribute to indicate when rep; mov is recoverable, and gate the > hotplug policy on the result. In my opinion a positive indicator of > the cpu's ability to recover rep; mov exceptions is a gap that needs > addressing. Is there some way to say "don't raise MC for this region"? Or at least limit it to a nonfatal one? Linus