Re: [PATCH 1 of 4 RFC] xen, p2m: get_entry returns level of entry as well

[George Dunlap <george.dunlap@eu.citrix.com>]

On 14/06/12 11:21, Tim Deegan wrote:
> At 12:54 +0100 on 08 Jun (1339160091), George Dunlap wrote:
>> Return the p2m level of the entry which filled this request.
>> Intended to be used to see if pages returned by the balloon
>> driver are part of a superpage, and reclaim them if so.
> This looks broadly correct, but it's a bit invasive.  If there's any way
> to rework patch 2 not to need it that would be helpful.  It looks like
> the main use is for detecting and removing superpage PoD entries; maybe
> that could be done with a sweep like you have in the non-PoD case?
You mean the non-balloon case?  I forget why I thought that was a bad 
idea, exactly.  Let me think about that.
> One niggle: returning level=5 on error is non-obvious, and it doesn't
> look like your code in patch 2 uses that.
Were you thinking -1 or something like that?

  -George