From: Dan Williams <dan.j.williams@intel.com>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Yumei Huang <yuhuang@redhat.com>, KVM <kvm@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: DAX can not work on virtual nvdimm device
Date: Tue, 30 Aug 2016 10:09:01 -0700 [thread overview]
Message-ID: <CAPcyv4hrFSxNcmmVLVZT4fK3+hspPCDKW0rVBj1=3GkJRgZ29Q@mail.gmail.com> (raw)
In-Reply-To: <61d5c470-a8bf-86d5-d1fe-b4b577a85967@linux.intel.com>
On Mon, Aug 29, 2016 at 11:53 PM, Xiao Guangrong
<guangrong.xiao@linux.intel.com> wrote:
>
>
> On 08/30/2016 03:30 AM, Ross Zwisler wrote:
>
>>
>> Can you please verify that you are using "usable" memory for your memmap?
>> All
>> the details are here:
>>
>>
>> https://nvdimm.wiki.kernel.org/how_to_choose_the_correct_memmap_kernel_parameter_for_pmem_on_your_system
>
>
> Sure.
>
> This is the BIOS E820 info in the guest:
>
> e820: BIOS-provided physical RAM map:
> BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
> BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
> BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
> BIOS-e820: [mem 0x0000000000100000-0x00000000bffdefff] usable
> BIOS-e820: [mem 0x00000000bffdf000-0x00000000bfffffff] reserved
> BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
> BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
> BIOS-e820: [mem 0x0000000100000000-0x000000083fffffff] usable
> NX (Execute Disable) protection: active
> e820: user-defined physical RAM map:
> user: [mem 0x0000000000000000-0x000000000009fbff] usable
> user: [mem 0x000000000009fc00-0x000000000009ffff] reserved
> user: [mem 0x00000000000f0000-0x00000000000fffff] reserved
> user: [mem 0x0000000000100000-0x00000000bffdefff] usable
> user: [mem 0x00000000bffdf000-0x00000000bfffffff] reserved
> user: [mem 0x00000000feffc000-0x00000000feffffff] reserved
> user: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
> user: [mem 0x0000000100000000-0x000000027fffffff] usable
> user: [mem 0x0000000280000000-0x00000003ffffffff] persistent (type 12)
> user: [mem 0x0000000400000000-0x000000083fffffff] usable
>
> So that the memory we used to emulate PMEM split the 'usable' region.
>
>>
>> My guess is that Boaz was correct, and that your memmap is off using
>> addresses
>> that don't actually map to memory.
>
>
> I do not think so. :(
>
> I did mmap-write and mmap-read test, the data written by mmap-write can be
> correctly read out, so that the backend memory is really existing.
>
Can you post your exact reproduction steps? This test is not failing for me.
next prev parent reply other threads:[~2016-08-30 17:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-19 11:19 DAX can not work on virtual nvdimm device Xiao Guangrong
2016-08-19 14:59 ` Dan Williams
2016-08-19 18:30 ` Ross Zwisler
2016-08-21 9:55 ` Boaz Harrosh
2016-08-29 7:54 ` Xiao Guangrong
2016-08-29 19:30 ` Ross Zwisler
2016-08-30 6:53 ` Xiao Guangrong
2016-08-30 17:09 ` Dan Williams [this message]
2016-08-31 8:44 ` Xiao Guangrong
2016-08-31 16:46 ` Ross Zwisler
2016-09-02 2:57 ` Ross Zwisler
2016-09-06 15:06 ` Jan Kara
2016-09-08 20:47 ` Ross Zwisler
2016-09-09 9:19 ` Jan Kara
2016-09-09 14:03 ` Theodore Ts'o
2016-09-09 16:34 ` Ross Zwisler
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