Re: [Qemu-devel] broken incoming migration

[Peter Lieven]

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