Re: [Xen-devel] [RFC PATCH] page_alloc: use first half of higher order chunks when halving

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.04.14 at 00:21, <mvrushton@xxxxxxxxx> wrote:
> On 04/02/14 03:20, Ian Campbell wrote:
>> Dom0 ballooning breaks any assumptions you might make about relying on
>> early allocations.
> 
> I think you're missing the point. I'm not arguing that this change is a 
> general purpose solution to guarantee that dom0 is contiguous. 
> Fragmentation can exist even if dom0 asks for larger allocations like it 
> should (which the balloon driver does I believe). What the change does 
> do is solve a real problem in the current Linux PCI remapping 
> implementation which happens during dom0 intialization. If the 
> allocation strategy is arbitrary why not make the proposed hypervisor 
> change to make existing Linux implementations behave better and in 
> addition fix the problem in Linux so moving forward things are safe?

Apart from all other arguments speaking against this, did you
consider that altering the hypervisor behavior may adversely
affect some other Dom0-capable OS?

Problems in Linux should, as said before, get fixed in Linux. If
older versions are affected, stable backports should subsequently
be requested/done.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel