From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f45.google.com (mail-oi0-f45.google.com [209.85.218.45]) by kanga.kvack.org (Postfix) with ESMTP id 60E8B6B0038 for ; Mon, 23 Nov 2015 16:08:46 -0500 (EST) Received: by oige206 with SMTP id e206so140350874oig.2 for ; Mon, 23 Nov 2015 13:08:46 -0800 (PST) Received: from g4t3428.houston.hp.com (g4t3428.houston.hp.com. [15.201.208.56]) by mx.google.com with ESMTPS id ro4si9491491oeb.94.2015.11.23.13.08.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Nov 2015 13:08:45 -0800 (PST) Message-ID: <1448312664.19320.9.camel@hpe.com> Subject: Re: [PATCH] dax: Split pmd map when fallback on COW From: Toshi Kani Date: Mon, 23 Nov 2015 14:04:24 -0700 In-Reply-To: References: <1448309120-20911-1-git-send-email-toshi.kani@hpe.com> <1448311559.19320.2.camel@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 Williams Cc: "Kirill A. Shutemov" , Matthew Wilcox , Ross Zwisler , Linux MM , linux-fsdevel , "linux-nvdimm@lists.01.org" , "linux-kernel@vger.kernel.org" On Mon, 2015-11-23 at 12:56 -0800, Dan Williams wrote: > On Mon, Nov 23, 2015 at 12:45 PM, Toshi Kani wrote: > > On Mon, 2015-11-23 at 12:45 -0800, Dan Williams wrote: > > > On Mon, Nov 23, 2015 at 12:05 PM, Toshi Kani wrote: > [..] > > > This is a nop if CONFIG_TRANSPARENT_HUGEPAGE=n, so I don't think it's > > > a complete fix. > > > > Well, __dax_pmd_fault() itself depends on CONFIG_TRANSPARENT_HUGEPAGE. > > > > Indeed it is... I think that's wrong because transparent huge pages > rely on struct page?? I do not think this issue is related with struct page. wp_huge_pmd() calls either do_huge_pmd_wp_page() or dax_pmd_fault(). do_huge_pmd_wp_page() splits a pmd page when it returns with VM_FAULT_FALLBACK. So, this change keeps them consistent on VM_FAULT_FALLBACK. Thanks, -Toshi -- 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