Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754604AbdFWWU4 convert rfc822-to-8bit (ORCPT ); Fri, 23 Jun 2017 18:20:56 -0400 Received: from g2t1383g.austin.hpe.com ([15.233.16.89]:57785 "EHLO g2t1383g.austin.hpe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753942AbdFWWUy (ORCPT ); Fri, 23 Jun 2017 18:20:54 -0400 From: "Elliott, Robert (Persistent Memory)" To: "Luck, Tony" , Borislav Petkov CC: Dave Hansen , Naoya Horiguchi , "x86@kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Yazen Ghannam , "Kani, Toshimitsu" , "'dan.j.williams@intel.com'" , "linux-nvdimm@lists.01.org" Subject: RE: [PATCH] mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages Thread-Topic: [PATCH] mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages Thread-Index: AQHS6SY7NIkyryuYLUCNcd9KLhmfHaIvmqcAgANumbA= Date: Fri, 23 Jun 2017 22:19:35 +0000 Message-ID: References: <20170616190200.6210-1-tony.luck@intel.com> <20170619180147.qolal6mz2wlrjbxk@pd.tnic> <20170621174740.npbtg2e4o65tyrss@intel.com> In-Reply-To: <20170621174740.npbtg2e4o65tyrss@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: intel.com; dkim=none (message not signed) header.d=none;intel.com; dmarc=none action=none header.from=hpe.com; x-originating-ip: [15.203.227.2] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;AT5PR84MB0098;7: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 x-forefront-antispam-report: SFV:SKI;SCL:-1SFV:NSPM;SFS:(10019020)(6009001)(39840400002)(39860400002)(39410400002)(39450400003)(39400400002)(39850400002)(5250100002)(55016002)(8676002)(8936002)(81166006)(8666007)(14454004)(25786009)(4326008)(66066001)(2906002)(189998001)(6506006)(305945005)(33656002)(3280700002)(74316002)(478600001)(6116002)(102836003)(38730400002)(3660700001)(229853002)(50986999)(7416002)(6436002)(76176999)(5660300001)(54356999)(86362001)(7696004)(53936002)(6246003)(9686003)(3846002)(2900100001)(2950100002)(54906002);DIR:OUT;SFP:1102;SCL:1;SRVR:AT5PR84MB0098;H:AT5PR84MB0082.NAMPRD84.PROD.OUTLOOK.COM;FPR:;SPF:None;MLV:sfv;LANG:en; x-ms-office365-filtering-correlation-id: 5b7b2bda-ea9e-4ed0-e326-08d4ba85ee2b x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(2017030254075)(48565401081)(201703131423075)(201703031133081)(201702281549075);SRVR:AT5PR84MB0098; x-ms-traffictypediagnostic: AT5PR84MB0098: x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(236129657087228); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(6040450)(601004)(2401047)(8121501046)(5005006)(10201501046)(100000703101)(100105400095)(3002001)(93006095)(93001095)(6055026)(6041248)(20161123560025)(20161123562025)(20161123555025)(20161123558100)(20161123564025)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(6072148)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:AT5PR84MB0098;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:AT5PR84MB0098; x-forefront-prvs: 0347410860 spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Jun 2017 22:19:35.4102 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-Transport-CrossTenantHeadersStamped: AT5PR84MB0098 X-OriginatorOrg: hpe.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 600 Lines: 17 > > > + if (set_memory_np(decoy_addr, 1)) > > > + pr_warn("Could not invalidate pfn=0x%lx from 1:1 map \n", Another concept to consider is mapping the page as UC rather than completely unmapping it. The uncorrectable error scope could be smaller than a page size, like: * memory ECC width (e.g., 8 bytes) * cache line size (e.g., 64 bytes) * block device logical block size (e.g., 512 bytes, for persistent memory) UC preserves the ability to access adjacent data within the page that hasn't gone bad, and is particularly useful for persistent memory. --- Robert Elliott, HPE Persistent Memory