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[198.145.29.99]) by mx.google.com with ESMTPS id p2si28021813pls.31.2019.05.02.10.34.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 May 2019 10:34:26 -0700 (PDT) Received-SPF: pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=hp6CAJKt; spf=pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sashal@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from localhost (adsl-173-228-226-134.prtc.net [173.228.226.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C09C5205F4; Thu, 2 May 2019 17:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556818466; bh=k1Mng5fkxG2kqXsRSaQDBN/3qrjtIBnMdTR42nRFITQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hp6CAJKtym6IoN734hnJoB9bKolzpSd0R7qRYpUjsgNKYsINuqSetNrT1/y1xcNaN 6xMHqCPis63NBoZhcvCRXmKfvQQYWd1l/DP9A5DA3xV1FqO6dXcr1bM8eS8DJT8DaH JFX5NmJuqQJsTHn1vYCIS0QS8K+KpZZYBJoG9Pjs= Date: Thu, 2 May 2019 13:34:19 -0400 From: Sasha Levin To: Pavel Tatashin Cc: jmorris@namei.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, akpm@linux-foundation.org, mhocko@suse.com, dave.hansen@linux.intel.com, dan.j.williams@intel.com, keith.busch@intel.com, vishal.l.verma@intel.com, dave.jiang@intel.com, zwisler@kernel.org, thomas.lendacky@amd.com, ying.huang@intel.com, fengguang.wu@intel.com, bp@suse.de, bhelgaas@google.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de, jglisse@redhat.com, david@redhat.com Subject: Re: [v4 2/2] device-dax: "Hotremove" persistent memory that is used like normal RAM Message-ID: <20190502173419.GA3048@sasha-vm> References: <20190501191846.12634-1-pasha.tatashin@soleen.com> <20190501191846.12634-3-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190501191846.12634-3-pasha.tatashin@soleen.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Wed, May 01, 2019 at 03:18:46PM -0400, Pavel Tatashin wrote: >It is now allowed to use persistent memory like a regular RAM, but >currently there is no way to remove this memory until machine is >rebooted. > >This work expands the functionality to also allows hotremoving >previously hotplugged persistent memory, and recover the device for use >for other purposes. > >To hotremove persistent memory, the management software must first >offline all memory blocks of dax region, and than unbind it from >device-dax/kmem driver. So, operations should look like this: > >echo offline > echo offline > /sys/devices/system/memory/memoryN/state This looks wrong :) -- Thanks, Sasha