Re: [PATCH] VMware Balloon driver

[Avi Kivity <avi@redhat.com>]

On 04/06/2010 09:25 PM, Jeremy Fitzhardinge wrote:
> On 04/06/2010 09:32 AM, Avi Kivity wrote:
>> Yeah.  If we wanted commonality, we could make a balloon_core.c that 
>> contains the common code.  IMO that's premature, but perhaps there's 
>> some meat there (like suspend/resume support and /proc//sys interface).
>
> I think it would be useful to have common:
>
>   1. User and kernel mode ABIs for controlling ballooning.  It assumes
>      that the different balloon implementations are sufficiently
>      similar in semantics.   (Once there's a kernel ABI, adding a
>      common user ABI is trivial.)
>   2. Policy driving the ballooning driver, at least from the guest
>      side.  That is, some good metrics from the vm subsystem about
>      memory pressure (both positive and negative), and something to
>      turn those metrics into requests to the balloon driver.
>
> 1) is not a huge amount of code, but something consistent would be 
> nice.  2) is something we've been missing and is a bit of an open 
> question/research project anyway.

3) Code that attempts to reclaim 2MB pages when possible

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.