From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x232.google.com (mail-oi0-x232.google.com [IPv6:2607:f8b0:4003:c06::232]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id C420F2264A1FE for ; Wed, 4 Apr 2018 07:48:24 -0700 (PDT) Received: by mail-oi0-x232.google.com with SMTP id u141-v6so19483089oif.1 for ; Wed, 04 Apr 2018 07:48:24 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20180404143713.t4lsufodbe7pr2jm@XZHOUW.usersys.redhat.com> References: <20180404143713.t4lsufodbe7pr2jm@XZHOUW.usersys.redhat.com> From: Dan Williams Date: Wed, 4 Apr 2018 07:48:23 -0700 Message-ID: Subject: Re: Can't hit dax pmd fault on nvdimm in raw mode List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Xiong Zhou Cc: linux-nvdimm List-ID: On Wed, Apr 4, 2018 at 7:37 AM, Xiong Zhou wrote: > Hi, > > It works fine in memory mode. Both tested on latest Linus tree with xfs. > > Referring https://nvdimm.wiki.kernel.org/2mib_fs_dax > > Did I miss anything? No, this behavior is by design. See commit ee82c9ed41e8 "dax: disable pmd mappings". The short summary is that struct page is needed to support get_user_pages() on dax pmd mappings, and raw mappings do not provide struct page. Details here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee82c9ed41e8 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm