From: Pankaj Gupta <pagupta@redhat.com>
To: Zhang Yi <yi.z.zhang@linux.intel.com>
Cc: jack@suse.cz, yu c zhang <yu.c.zhang@intel.com>,
kvm@vger.kernel.org, linux-nvdimm@lists.01.org,
rkrcmar@redhat.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, pbonzini@redhat.com, hch@lst.de,
yi z zhang <yi.z.zhang@intel.com>
Subject: Re: [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory
Date: Thu, 9 Aug 2018 05:23:28 -0400 (EDT) [thread overview]
Message-ID: <872818364.892078.1533806608252.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <2b7856596e519130946c834d5d61b00b7f592770.1533811181.git.yi.z.zhang@linux.intel.com>
>
> 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 <yi.z.zhang@linux.intel.com>
> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com>
> ---
> 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
>
>
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next prev parent reply other threads:[~2018-08-09 9:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-09 10:52 [PATCH V3 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio Zhang Yi
2018-08-09 9:02 ` Jan Kara
2018-08-13 17:33 ` Zhang,Yi
2018-08-09 10:52 ` [PATCH V3 1/4] kvm: remove redundant reserved page check Zhang Yi
2018-08-09 9:13 ` Pankaj Gupta
2018-08-10 11:23 ` David Hildenbrand
2018-08-09 10:53 ` [PATCH V3 2/4] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Zhang Yi
2018-08-09 8:59 ` Jan Kara
2018-08-09 10:53 ` [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory Zhang Yi
2018-08-09 9:23 ` Pankaj Gupta [this message]
2018-08-13 17:41 ` Zhang,Yi
2018-08-13 14:29 ` Jerome Glisse
2018-08-09 10:53 ` [PATCH V3 4/4] kvm: add a check if pfn is from NVDIMM pmem Zhang Yi
2018-08-09 8:32 ` Pankaj Gupta
2018-08-13 17:32 ` Zhang,Yi
2018-08-10 13:27 ` [PATCH V3 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio David Hildenbrand
2018-08-13 17:25 ` Zhang,Yi
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