From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41F84C46460 for ; Thu, 9 Aug 2018 09:23:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0C1E21B32 for ; Thu, 9 Aug 2018 09:23:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0C1E21B32 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730327AbeHILr0 (ORCPT ); Thu, 9 Aug 2018 07:47:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47222 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727579AbeHILr0 (ORCPT ); Thu, 9 Aug 2018 07:47:26 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B110730E686C; Thu, 9 Aug 2018 09:23:28 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9A12C65F7F; Thu, 9 Aug 2018 09:23:28 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 818784BB78; Thu, 9 Aug 2018 09:23:28 +0000 (UTC) Date: Thu, 9 Aug 2018 05:23:28 -0400 (EDT) From: Pankaj Gupta To: Zhang Yi Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan j williams , jack@suse.cz, hch@lst.de, yu c zhang , linux-mm@kvack.org, rkrcmar@redhat.com, yi z zhang Message-ID: <872818364.892078.1533806608252.JavaMail.zimbra@redhat.com> In-Reply-To: <2b7856596e519130946c834d5d61b00b7f592770.1533811181.git.yi.z.zhang@linux.intel.com> References: <2b7856596e519130946c834d5d61b00b7f592770.1533811181.git.yi.z.zhang@linux.intel.com> Subject: Re: [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.117.219, 10.4.195.24] Thread-Topic: add a function to differentiate the pages is from DAX device memory Thread-Index: R6K/BJ3yr4CsL362QJ204GQv/2NwBg== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Thu, 09 Aug 2018 09:23:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > DAX driver hotplug the device memory and move it to memory zone, these > pages will be marked reserved flag, however, some other kernel componet > will misconceive these pages are reserved mmio (ex: we map these dev_dax > or fs_dax pages to kvm for DIMM/NVDIMM backend). Together with the type > MEMORY_DEVICE_FS_DAX, we can use is_dax_page() to differentiate the pages > is DAX device memory or not. > > Signed-off-by: Zhang Yi > Signed-off-by: Zhang Yu > --- > include/linux/mm.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 68a5121..de5cbc3 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -889,6 +889,13 @@ static inline bool is_device_public_page(const struct > page *page) > page->pgmap->type == MEMORY_DEVICE_PUBLIC; > } > > +static inline bool is_dax_page(const struct page *page) > +{ > + return is_zone_device_page(page) && > + (page->pgmap->type == MEMORY_DEVICE_FS_DAX || > + page->pgmap->type == MEMORY_DEVICE_DEV_DAX); > +} I think question from Dan for KVM VM with 'MEMORY_DEVICE_PUBLIC' still holds? I am also interested to know if there is any use-case. Thanks, Pankaj > + > #else /* CONFIG_DEV_PAGEMAP_OPS */ > static inline void dev_pagemap_get_ops(void) > { > @@ -912,6 +919,11 @@ static inline bool is_device_public_page(const struct > page *page) > { > return false; > } > + > +static inline bool is_dax_page(const struct page *page) > +{ > + return false; > +} > #endif /* CONFIG_DEV_PAGEMAP_OPS */ > > static inline void get_page(struct page *page) > -- > 2.7.4 > >