Re: [Qemu-devel] broken incoming migration

[liu ping fan]

Hi Peter,

Is it that sending zero page mostly service the first iteration, ie
bluk-stage? And for the subsequent iteration, dirty pages are normally
not zero.

Thanks

On Wed, Jun 5, 2013 at 2:09 PM, Peter Lieven <address@hidden> wrote:
>
> Am 05.06.2013 um 05:37 schrieb Alexey Kardashevskiy <address@hidden>:
>
>> On 06/05/2013 05:15 AM, Peter Lieven wrote:
>>>
>>> Am 04.06.2013 um 17:17 schrieb Paolo Bonzini <address@hidden>:
>>>
>>>> Il 04/06/2013 16:48, Peter Lieven ha scritto:
>>>>> Still using 3.2, but strange enough the above example is also not
>>>>> increasing RSS size for me.
>>>>>
>>>>> Can you try the following:
>>>>> qemu git master with 1G of memory (hanging in bios with no boot device)
>>>>> and migrate it. Before migration RSS Size os somewhat
>>>>> around 16MB. After migration its RSS size is in the order of 1G.
>>>>
>>>> That may be a kernel bug.  The kernel did not do the copy-on-write trick
>>>> on huge zero pages.  It was fixed last year, maybe 3.2 is not enough.
>>>> Try adding a MADV_HUGEPAGE madvise to the testcase and see if it 
>>>> reproduces.
>>>
>>> that's it. thanks for the pointer. the huge zero page was introduced in 3.8.
>>>
>>> paolo, alexey: can you please verify the following works for you:
>>> https://github.com/plieven/qemu/tree/fix-migration
>>
>> These two?
>> 848b796 Tue Jun 4 14:43:04 2013 +0200 Peter Lieven migration: do not
>> overwrite zero pages
>> 2206ac8 Tue Jun 4 14:25:33 2013 +0200 Peter Lieven Revert "migration: do
>> not sent zero pages in bulk stage"
>
> Yes, sorry forgot to mention this.
>
>>
>> That works for me (qemu 1.5, kernel 3.9-rc2).
>> Tested-by: Alexey Kardashevskiy <address@hidden>
>
> Thank you,
> Peter