Re: [kvm-devel] [GIT PULL][RESEND] KVM cpu hotplug fixes

Avi Kivity
2007-06-02T07:33:16Z

Jun Koi wrote:
> Hi Avi,
>
> On 6/2/07, Avi Kivity <avi@qumranet.com> wrote:
>> Linus Torvalds wrote:
>> > Don't send me pull requests like this. And absolutely do NOT send
>> them as
>> > resends. I just get grumpy.
>> >
>> > If all the added code had been KVM-only, I might not care. But when
>> the
>> > bulk of the code touches core files, you had better explain why
>> this is so
>> > important that it cannot wait for the next merge window.
>>
>> Ok. This was really wanted by laptop-carrying users, but I guess
>> they'll have to wait for 2.6.23.
>>
>
> Could you explain a bit:
>
> 1) Why CPU hotplug is that important for virtualization?
>

It's not specifically important for virtualization. It's a Linux kernel
feature, and right now it doesn't work very well when kvm is enabled,
and that should be fixed.

> 2) Why this patch is wanted by laptop users?

CPU hotplug is used by suspend/resume (basically, suspend hot-unplugs
all cpus except one an then suspends the machine. Resume hotplugs the
cpus back after restarting the devices).

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