Date: Mon, 13 May 2013 16:01:26 -0400
From: Luiz Capitulino <lcapitulino@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org, riel@redhat.com,
        amit.shah@redhat.com, anton@enomsg.org
Subject: Re: [RFC 2/2] virtio_balloon: auto-ballooning support
Message-ID: <20130513160126.4d196719@redhat.com>
In-Reply-To: <20130513190250.GA2496@redhat.com>
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On Mon, 13 May 2013 22:02:50 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, May 13, 2013 at 02:25:11PM -0400, Luiz Capitulino wrote:
> > On Mon, 13 May 2013 11:34:41 -0300
> > Rafael Aquini <aquini@redhat.com> wrote:
> > 
> > > You're right, and the host's member is used to communicate the configured size
> > > to guest's balloon device, however, by not changing it when the shrinker causes 
> > > the balloon to deflate will make the balloon thread to be woken up again 
> > > in order to chase the balloon size target again, won't it? Check
> > 
> > I don't see the balloon thread waking up after the shrinker executes in my
> > testing. Maybe this is so because it will only wake up when QEMU notifies
> > a config change.
> 
> Well that's also a problem.
> Need some mechanism to re-inflate balloon

In this implemention this is done by QEMU, have you looked at the QEMU
patch yet?

 https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg01295.html

> when guest memory pressure is down.

In this implementation we do this when there's pressure in the host. I expect
things to balance over time, and this seems to be what I'm observing in my
testing, but of course we need more testing.

> virtio fs mechanism worth a look?

Can you elaborate?
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