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[209.85.220.65]) by mx.google.com with SMTPS id d63sor1427809oia.81.2019.05.15.13.26.28 for (Google Transport Security); Wed, 15 May 2019 13:26:28 -0700 (PDT) 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=SAIOuCey; 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=CNowSPd6xUM0oSrW52wC5X6N9h9RHW9ouHTqZZOyPB4=; b=SAIOuCey/H4PDGjItNH6MJbpdQ6eVphhRbi02FoQ/YOnoYGxaydqsOYiVIAO/t3q68 0i+LFQ13vsz1bj8cCiXxLi+GMY0PpVS/n4Tnm/fMII2aHygPYzSJnwoWDtPiIo9XVU4B UF+xwmZUZQ0W+oJace3RMwVkn3Iuq8GIugGZdBu4qRRMMPgZWHzuG5COUhU0vp87nTs/ FG1JFG1PtJ3RikGbUfL/NJErfucnwOSQDnoR242LrP2jVHyNv6FXHEZUgTRCbyr9ydcG Lyzzv47sX90bEqpeR7WfOo7msFCsrbGa0h1IuogufITOeuGE2XDwd6+gyOeGA8Z7o+W9 OqGg== X-Google-Smtp-Source: APXvYqx3oc7K1TBy0FDWKi5FhWmRYToljSQrlPDbQpttbtlguEoDEhZRGEYR3NAHlPXP6/3HQG4xvypvNp6sEKcLSAk= X-Received: by 2002:aca:4208:: with SMTP id p8mr8481558oia.105.1557951987781; Wed, 15 May 2019 13:26:27 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Dan Williams Date: Wed, 15 May 2019 13:26:16 -0700 Message-ID: Subject: Re: [GIT PULL] device-dax for 5.1: PMEM as RAM To: Linus Torvalds Cc: Linux Kernel Mailing List , linux-nvdimm , Linux MM , Dave Hansen , "Luck, Tony" , Vishal L Verma 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: On Mon, Mar 11, 2019 at 5:08 PM Linus Torvalds wrote: > > 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. In case anyone is looking for the above mentioned tooling for use with the v5.1 kernel, Vishal has released ndctl-v65 with the new "clear-errors" command [1]. [1]: https://pmem.io/ndctl/ndctl-clear-errors.html