This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: Re: [Xen-devel] Balloon driver for Linux/HVM

To: George Dunlap <dunlapg@xxxxxxxxx>, Xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: Re: [Xen-devel] Balloon driver for Linux/HVM
From: Chu Rui <ruichu@xxxxxxxxx>
Date: Tue, 16 Nov 2010 23:37:12 +0800
Delivery-date: Tue, 16 Nov 2010 07:38:01 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=qnF49Uz3AUe+/kGeZPe0bJ0Drur2Z5E+OJCa1NMKLuY=; b=HzComhqzCTrPEOv9DRkjFhyzvDlmxNtZan00pfhPJd0jUB3m/5bZINqoIJ1hMMF2jo 0tGQ9IGkYbX1S4uyFL4WHKdgOGrJWw+23FTfxi3DwD0yqXP9vHdEXocUf5v5Uy6VkrtB JRhuNK3xMYUi5Hky43JAPBm01uRVLNiZIv5pY=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=PdhMpSbqOWkxCrlDJVwjedHwYt3ca2V+AUTpXQwm3G3OJt479Ng4WWcyHxD36+17gF bRKknjuxSpC4rsnROnNRlqSP2yPzNO3GQph1Mow83Mn4WjuQ3dWwFUQWRonT10TIqLK8 n2d9ece7b8/NYEecJnRke1etACZvCz7u3EhiQ=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <AANLkTinEEc=3rFaoWBPrD4zrGU_dqR5s4rmW74jJH543@xxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTimG5Z3FFrKc21Mtfg-q3eF-aEPEeWZ1cfEDqB7D@xxxxxxxxxxxxxx> <alpine.DEB.2.00.1011161133350.2373@kaball-desktop> <1ae18b.16279.12c547ff769.Coremail.topperxin@xxxxxxx> <AANLkTinEEc=3rFaoWBPrD4zrGU_dqR5s4rmW74jJH543@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thank you for your kind reply, George.
I am interested on the PoD memory. In my perspective, PoD mainly works in the system initialization stage. Before the balloon driver begins to work, it can limit the  memory consumption of the guests. However, after a while the guest OS will commit more memory, but PoD cannot reclaim any more at that time even when the committed pages is IO cache. While the balloon keeps work all of the time.

Would you please tell me whether my thought is correct?

Actually, in my opinion, the guest IO cache is mostly useless, since the Dom0 will cache the IO operations. Such a double-cache wastes the memory resources. Is there any good idea for that like Transcendent Memory while works with HVM?

在 2010年11月16日 下午8:56,George Dunlap <dunlapg@xxxxxxxxx>写道:
2010/11/16 牛立新 <topperxin@xxxxxxx>:
> o, it's strange, the old version have no this limitation.

No; unfortunately a great deal of functionality present in "classic
xen" has been lost in the process of getting the core dom0 support
into the pvops kernel.  I think the plan is, once we have the
necessary changes to non-xen code pushed up stream, we can start
working on getting feature parity with classic xen.

> At 2010-11-16 19:35:50,"Stefano Stabellini" <stefano.stabellini@xxxxxxxxxxxxx> wrote:
>>On Tue, 16 Nov 2010, Chu Rui wrote:
>>> Hi,
>>> I have noticed that, in the code of linux/drivers/xen/balloon.c, there exists the snippet as this:
>>> static int __init balloon_init(void)
>>> {
>>> unsigned long pfn;
>>> struct page *page;
>>> if (!xen_pv_domain())
>>> return -ENODEV;
>>> .....
>>> }
>>> Does it means the driver will not work in HVM? If so, where is the HVN-enabled code for that?
>>not yet, even though I have a patch ready to enable it:
>>git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git 2.6.36-rc7-pvhvm-v1
> ________________________________
> 网易163/126邮箱百分百兼容iphone ipad邮件收发
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

Xen-devel mailing list