Re: [PATCH 0 of 4] videoram allocation and stdvga improvements

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Samuel Thibault wrote:

> Samuel Thibault, le Tue 13 Jan 2009 15:01:08 +0100, a écrit :
>> Stefano Stabellini, le Tue 13 Jan 2009 12:17:47 +0000, a écrit :
>>> In order to simplify the codepath and the libxc API, this patch series
>>> removes the videoram allocation code from hvmloader and lets qemu do the
>>> job, using xc_domain_memory_populate_physmap.
>> That's what it was doing before I made hvmloader do it.  The reason was
>> to make save/restore work fine with stubdomains dirty log, etc.
> 
> Ah, now I remember the precise reason, written in the 18383 changelog:
> 
> When creating an HVM domain, if e.g. another domain is created before
> qemu allocates video memory, the extra 8MB memory ballooning is not
> available any more, because it got consumed by the other domain.
> 

The current design of the autoballoner is limited, as a consequence the
autoballoner is racy and it should not be used at all if the user plans
to start multiple domains at the same time.