Re: [PATCH][RFC] kvm-scheduler integration

[Avi Kivity <avi@qumranet.com>]

Ingo Molnar wrote:
> * Avi Kivity <avi@qumranet.com> wrote:
>
>   
>>>> +#ifdef CONFIG_SCHED_KVM
>>>> +static __read_mostly struct sched_kvm_hooks kvm_hooks;
>>>> +#endif
>>>>         
>>> please just add a current->put_vcpu() function pointer instead of 
>>> this hooks thing.
>>>       
>> Won't that increase task_struct (16 bytes on 64-bit) unnecessarily?  
>> The function pointers are common to all virtual machines.
>>     
>
> well, this function pointer could then be reused by other virtual 
> machines as well, couldnt it? 

I don't get this.  If we add a couple of members to task_struct, it 
can't be reused.  The values will be the same across all tasks, but the 
memory will be gone (including tasks which aren't virtual machines).

> If the task struct overhead is a problem 
> (it really isnt, and it's dependent on CONFIG_KVM) then we could switch 
> it around to a notifier-alike mechanism.
>   

I'm hoping that CONFIG_KVM will be enabled on most distro kernels, so we 
need to optimize for that case as well.

-- 
error compiling committee.c: too many arguments to function