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From: David Vrabel <david.vrabel@citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>,
	Oliver Chick <oliver.chick@citrix.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Jan Beulich <JBeulich@suse.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [Xen-devel] [PATCH] Persistent grant maps for xen blk drivers
Date: Fri, 21 Sep 2012 17:17:36 +0100	[thread overview]
Message-ID: <505C9320.8030905@citrix.com> (raw)
In-Reply-To: <20120921142733.GB3389@phenom.dumpdata.com>

On 21/09/12 15:27, Konrad Rzeszutek Wilk wrote:
> On Fri, Sep 21, 2012 at 01:23:48PM +0100, David Vrabel wrote:
>>
>> It's not just virtual space.  blkback in pvops kernels allocates its
>> pages from the balloon and if there aren't enough ballooned out pages it
>> has to allocate real pages (releasing the MFN back to Xen).
>>
>> Classic kernels didn't need to do this as there was an API for allocate
>> new "empty" struct page's that get mapped into kernel space.
> 
> Can we ressurect/implement that in the new pvops? We could use the memory
> hotplug mechanism to allocate "non-existent" memory. 

I don't see why not.  Provided the limitations are documented I wouldn't
make merging the persistent grant stuff dependent on it.

David

  reply	other threads:[~2012-09-21 16:17 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-19 10:51 [PATCH] Persistent grant maps for xen blk drivers Oliver Chick
2012-09-19 11:17 ` Konrad Rzeszutek Wilk
2012-09-19 12:03 ` [Xen-devel] " Jan Beulich
2012-09-20  8:51   ` Oliver Chick
2012-09-20  9:11     ` Jan Beulich
2012-09-19 13:16 ` Pasi Kärkkäinen
2012-09-20  9:35   ` Oliver Chick
2012-09-20 10:09     ` Pasi Kärkkäinen
2012-09-19 14:11 ` Konrad Rzeszutek Wilk
2012-09-20 13:12   ` Oliver Chick
2012-09-20 13:52     ` Konrad Rzeszutek Wilk
2012-09-20 10:34 ` [Xen-devel] " David Vrabel
2012-09-20 11:30   ` Oliver Chick
2012-09-20 11:48     ` Jan Beulich
2012-09-20 13:49       ` Konrad Rzeszutek Wilk
2012-09-20 14:13         ` Oliver Chick
2012-09-20 16:10           ` Jan Beulich
2012-09-20 21:24           ` Konrad Rzeszutek Wilk
2012-09-21  7:18             ` Jan Beulich
2012-09-21  8:41               ` Oliver Chick
2012-09-21  9:41                 ` Jan Beulich
2012-09-21  8:10             ` Ian Campbell
2012-09-21 14:26               ` Konrad Rzeszutek Wilk
2012-09-20 15:35         ` Jan Beulich
2012-09-21 12:23       ` David Vrabel
2012-09-21 14:27         ` Konrad Rzeszutek Wilk
2012-09-21 16:17           ` David Vrabel [this message]
2012-09-21 17:13             ` Konrad Rzeszutek Wilk

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