[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Xen-devel] [RFC][PATCH] 0/9 Populate-on-demand memory

>From: Tim Deegan [mailto:Tim.Deegan@xxxxxxxxxx] 
>Sent: Tuesday, December 30, 2008 5:27 PM
>At 15:46 +0000 on 24 Dec (1230133560), George Dunlap wrote:
>> On Wed, Dec 24, 2008 at 3:35 PM, Dan Magenheimer
>> <dan.magenheimer@xxxxxxxxxx> wrote:
>> >> We could to allocate a new page at that point; but it's 
>likely that
>> >> the allocation will fail unless there happens to be memory lying
>> >> around somewhere, not used by dom0 or any other doamin.  
>And if that
>> >> were the case, why not just start it with that much 
>memory to begin
>> >> with?
>> >
>> > Actually, if dom0_mem is used rather than the default of letting
>> > domain0 absorb all free memory and dole it as needed to launching
>> > VMs, there will almost always be some memory lying around.
>> At any rate, I suppose it might not be a bad idea to *try* 
>to allocate
>> more memory in an emergency.  I'll add that to the list of
>> improvements.
>Please don't do this.  It's not OK for a domain to start using more
>memory without the say-so of the tool stack.  Since this emergency
>condition means something has gone wrong (balloon driver failed to
>start) then you're probably just postponing the inevitable, and in the
>meantime you might cause problems for domains that *aren't* 

Then a user controlled option would fit here, which indicate whether
given domain is important and then emergency expansion could be
allowed in such case if mandatory kill is not acceptable.

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.