Re: [Xen-devel] PML (Page Modification Logging) design for Xen

[George Dunlap <dunlapg@xxxxxxxxx>]

On Tue, Feb 17, 2015 at 10:19 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 12.02.15 at 03:39, <kai.huang@xxxxxxxxxxxxxxx> wrote:
>> On 02/11/2015 07:52 PM, Andrew Cooper wrote:
>>> On 11/02/15 08:28, Kai Huang wrote:
>>>> Design
>>>> ======
>>>>
>>>> - PML feature is used globally
>>>>
>>>> A new Xen boot parameter, say 'opt_enable_pml', will be introduced to
>>>> control PML feature detection, and PML feature will only be detected
>>>> if opt_enable_pml = 1. Once PML feature is detected, it will be used
>>>> for dirty logging for all domains globally. Currently we don't support
>>>> to use PML on basis of per-domain as it will require additional
>>>> control from XL tool.
>>> Rather than adding in a new top level command line option for an ept
>>> subfeature, it would be preferable to add an "ept=" option which has
>>> "pml" as a sub boolean.
>> Which is good to me, if Jan agrees.
>>
>> Jan, which do you prefer here?
>
> A single "ept=" option as Andrew suggested.

Sorry to be coming late to this party -- what's the logic behind
having this enabled with "ept="? You're not changing anything about
how EPT itself works; you're adding a secondary feature which happens
to depend on ept.  Is there another hypervisor command-line option you
had in mind that works this way?

It might also be nice to be able to enable or disable this feature
with a sysctl call; but that's just a nice-to-have.

 -George

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