Re: [kvm-devel] [PATCH/RFC 4/4, second shot]KVM uses "account_guest_time()"

Avi Kivity
2007-08-17T13:03:23Z

Laurent Vivier wrote:
> KVM updates vtime in task_struct to allow account_guest_time() to modify user,
> system and guest time in cpustat accordingly.
>

> --- kvm.orig/drivers/kvm/Kconfig 2007-08-17 10:24:46.000000000 +0200
> +++ kvm/drivers/kvm/Kconfig 2007-08-17 10:25:25.000000000 +0200
> @@ -41,4 +41,10 @@
> Provides support for KVM on AMD processors equipped with the AMD-V
> (SVM) extensions.
>
> +config GUEST_ACCOUNTING
> + bool "Virtual Machine accounting support"
> + depends on KVM
> + ---help---
> + Allows to account CPU time used by the Virtual Machines.
> +

Other way round. In the patch that adds account_guest_time(), have a
CONFIG_GUEST_ACCOUNTING (defaulting to n, with no description, help, or
dependencies. Then, CONFIG_KVM can select GUEST_ACCOUNTING.

The advantages of this are:
- the puppyvisor can also select this if it so wishes
- we don't have core code reference some obscure module

CONFIG_PREEMPT_NOTIFIERS does the same thing.

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