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=1.4 required=3.0 tests=DATE_IN_FUTURE_03_06, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=no 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 80E93C46464 for ; Mon, 13 Aug 2018 09:57:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4369121728 for ; Mon, 13 Aug 2018 09:57:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4369121728 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.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 S1729056AbeHMMjK (ORCPT ); Mon, 13 Aug 2018 08:39:10 -0400 Received: from mga06.intel.com ([134.134.136.31]:28735 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728493AbeHMMjK (ORCPT ); Mon, 13 Aug 2018 08:39:10 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Aug 2018 02:57:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,232,1531810800"; d="scan'208";a="253630878" Received: from dazhang1-z97x.sh.intel.com (HELO [10.239.13.128]) ([10.239.13.128]) by fmsmga005.fm.intel.com with ESMTP; 13 Aug 2018 02:57:36 -0700 Subject: Re: [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory To: Pankaj Gupta , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= 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 References: <2b7856596e519130946c834d5d61b00b7f592770.1533811181.git.yi.z.zhang@linux.intel.com> <872818364.892078.1533806608252.JavaMail.zimbra@redhat.com> From: "Zhang,Yi" Message-ID: <5ea50e63-b55a-c1e1-50be-6e2d951c04cf@linux.intel.com> Date: Tue, 14 Aug 2018 01:41:40 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <872818364.892078.1533806608252.JavaMail.zimbra@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年08月09日 17:23, Pankaj Gupta wrote: >> 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 Yes, it is, thanks for your remind, Pankaj. Adding Jerome for Dan's questions on V1: [Dan]: Jerome, might there be any use case to pass MEMORY_DEVICE_PUBLIC memory to a guest vm? > >> + >> #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 >> >>