Re: [PATCH] Fix auto-ballooning of dom0 for HVM domains

["Charles Coffing" <ccoffing@novell.com>]

Sorry, I forgot the Signed-off-by line.  Consider this my sign-off on
the previous email:

Signed-off-by: Charles Coffing <ccoffing@novell.com>


>>> On Thu, May 18, 2006 at 11:04 AM, in message
<446C5554.D169.003C.0@novell.com>,
"Charles Coffing" <ccoffing@novell.com> wrote: 
> Hi,
> 
> I've been trying to make the auto- ballooning of domain 0 work
reliably
> for HVM domains.
> 
> Patch #1 is a simple bug fix, in preparation for patch #2.  Patch #2
> tries to calculate how much memory is needed for HVM domains
(XenSource
> bug #521) and is certainly open for discussion.  Patches apply
cleanly
> to both 3.0- testing and unstable.
> 
> Patch #1 (xen- hvm- auto- balloon.diff):
> When a domain (whether para-  or fully- virtualized) reports how
much
> overhead memory it requires (via getDomainMemory in image.py), all
such
> memory was immediately allocated to the domain itself.  This is
> certainly incorrect for HVM domains, since additional
> increase_reservation calls are made later in qemu.  Since all
ballooned
> memory is already taken, qemu will fail.  The fix is to treat the
> requested memory size and the overhead size as separate values.  The
> requested memory size is immediately allocated to the new domain;
the
> overhead is left unallocated for whatever else might need it later.
> 
> Patch #2 (xen- get- dom- memory.diff):
> This patch calculates the overhead needed for HVM domains.  If HVM
is
> supported by the hardware, I add a little ballooning overhead to
> paravirtualized VMs also, to avoid low- memory situations.  (There
are
> various unchecked alloc_domheap_pages calls in shadow*.c that I am
> trying to avoid tripping over for now...)  The values in this patch
work
> fine on 32 bit; I may update them later based on feedback and/or
testing
> on 64 bit.
> 
> Thanks,
> Chuck