From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f50.google.com (mail-oi0-f50.google.com [209.85.218.50]) by kanga.kvack.org (Postfix) with ESMTP id E282E6B0038 for ; Mon, 23 Nov 2015 18:03:08 -0500 (EST) Received: by oiww189 with SMTP id w189so142215925oiw.3 for ; Mon, 23 Nov 2015 15:03:08 -0800 (PST) Received: from g9t5009.houston.hp.com (g9t5009.houston.hp.com. [15.240.92.67]) by mx.google.com with ESMTPS id np6si9062765obc.26.2015.11.23.15.03.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Nov 2015 15:03:08 -0800 (PST) Message-ID: <1448319526.19320.58.camel@hpe.com> Subject: Re: [PATCH] dax: Split pmd map when fallback on COW From: Toshi Kani Date: Mon, 23 Nov 2015 15:58:46 -0700 In-Reply-To: <1448309120-20911-1-git-send-email-toshi.kani@hpe.com> References: <1448309120-20911-1-git-send-email-toshi.kani@hpe.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: dan.j.williams@intel.com Cc: kirill.shutemov@linux.intel.com, willy@linux.intel.com, ross.zwisler@linux.intel.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org On Mon, 2015-11-23 at 13:05 -0700, Toshi Kani wrote: > An infinite loop of PMD faults was observed when attempted to > mlock() a private read-only PMD mmap'd range of a DAX file. Typo: the above description should be (remove "read-only"): An infinite loop of PMD faults was observed when attempted to mlock() a private PMD mmap'd range of a DAX file. -Toshi > __dax_pmd_fault() simply returns with VM_FAULT_FALLBACK when > falling back to PTE on COW. However, __handle_mm_fault() > returns without falling back to handle_pte_fault() because > a PMD map is present in this case. > > Change __dax_pmd_fault() to split the PMD map, if present, > before returning with VM_FAULT_FALLBACK. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org