Re: [Qemu-devel] broken incoming migration

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 06/05/2013 05:15 AM, Peter Lieven wrote:
> 
> Am 04.06.2013 um 17:17 schrieb Paolo Bonzini <pbonzini@redhat.com>:
> 
>> 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"

That works for me (qemu 1.5, kernel 3.9-rc2).
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>



-- 
Alexey