Re: [Xen-devel] Runtime adjustment of hypervisor parameters

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 04/08/17 14:20, Juergen Gross wrote:
> Last year Jan posted a patch series to change hypervisor log level
> thresholds via xl command [1]. This approach was later modified by Wei
> resulting in patch series [2].
>
> I'd like to follow up with another approach being able to do the same,
> but being much more flexible:
>
> Instead of controlling only loglvl I suggest to add a xl command
>
> xl xen-param <parameters>
>
> which will take a <parameters> string being parsed by the hypervisor
> the same way it is parsing boot parameters. Allowed parameters are
> specified in the hypervisor the same way as boot parameters, but with
> another set of macros (e.g. custom_runtime_param(), ...). Often enough
> (e.g. in the loglvl case) the definitions could be just the same, while
> in other cases they might differ a little bit (example: conring_size
> would require a different handling as at boot time due to race
> condition handling).
>
> Parsing functions could be reused in most cases, they'd just need to
> lose the __init modifier.
>
> What do you think: is this approach sensible, or can I just put it into
> /dev/null instead of starting with the patches?

What sort of parameters were you thinking of tweaking?  (Without any
evidence) I'm going to go out on a limb and say that most of the
hypervisor command line parameters are not safe to play with after boot.

~Andrew

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