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From: Stefan Priebe <s.priebe@profihost.ag>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Orit Wasserman <owasserm@redhat.com>, Peter Lieven <pl@kamp.de>,
	qemu-devel <qemu-devel@nongnu.org>,
	Dave Gilbert <dgilbert@redhat.com>,
	Juan Quintela <quintela@redhat.com>
Subject: Re: [Qemu-devel] memory allocation of migration changed?
Date: Tue, 11 Feb 2014 19:30:54 +0100	[thread overview]
Message-ID: <52FA6C5E.1060300@profihost.ag> (raw)
In-Reply-To: <CAJSP0QWyA195Pdhy_juSimfnuPFTakwcHtN2beyJdE31ghgemQ@mail.gmail.com>

Am 11.02.2014 16:44, schrieb Stefan Hajnoczi:
> On Tue, Feb 11, 2014 at 3:54 PM, Stefan Priebe - Profihost AG
> <s.priebe@profihost.ag> wrote:
>> in the past (Qemu 1.5) a migration failed if there was not enogh memory
>> on the target host available directly at the beginning.
>>
>> Now with Qemu 1.7 i've seen succeeded migrations but the kernel OOM
>> memory killer killing qemu processes. So the migration seems to takes
>> place without having anough memory on the target machine?
>
> How much memory is the guest configured with?  How much memory does
> the host have?

Guest: 48GB
Host: 192GB

> I wonder if there are zero pages that can be migrated almost "for
> free" and the destination host doesn't touch.  When they are touched
> for the first time after migration handover, they need to be allocated
> on the destination host.  This can lead to OOM if you overcommitted
> memory.

In the past the migration failed immediatly with exit code 255.

> Can you reproduce the OOM reliably?  It should be possible to debug it
> and figure out whether it's just bad luck or a true regression.

So there is no known patch changing this behaviour?

What is about those?
fc1c4a5d32e15a4c40c47945da85ef9c1e0c1b54
211ea74022f51164a7729030b28eec90b6c99a08
f1c72795af573b24a7da5eb52375c9aba8a37972

Stefan

  parent reply	other threads:[~2014-02-11 18:30 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-11 14:54 [Qemu-devel] memory allocation of migration changed? Stefan Priebe - Profihost AG
2014-02-11 15:44 ` Stefan Hajnoczi
2014-02-11 16:22   ` Peter Lieven
2014-02-11 18:32     ` Stefan Priebe
2014-02-14 14:59       ` Stefan Hajnoczi
2014-02-14 18:15         ` Stefan Priebe
2014-02-11 18:30   ` Stefan Priebe [this message]
2014-02-14 15:03     ` Stefan Hajnoczi
2014-02-14 18:16       ` Stefan Priebe
2014-02-24 15:00         ` Stefan Hajnoczi
2014-02-24 16:13           ` Eric Blake
2014-03-12 19:15             ` Stefan Priebe

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