From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 681636B0010 for ; Mon, 13 Aug 2018 05:57:40 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id h5-v6so7045193pgs.13 for ; Mon, 13 Aug 2018 02:57:40 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTPS id t64-v6si18001763pfj.338.2018.08.13.02.57.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 Aug 2018 02:57:39 -0700 (PDT) Subject: Re: [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory 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 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: owner-linux-mm@kvack.org List-ID: 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 On 2018a1'08ae??09ae?JPY 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 >> >>