Re: [PATCH] KVM: PPC: Allocate vcpu struct using vmalloc

[Avi Kivity <avi@redhat.com>]

On 02/21/2010 04:50 PM, Alexander Graf wrote:
> On 21.02.2010, at 13:29, Avi Kivity wrote:
>
>    
>> On 02/19/2010 01:24 PM, Alexander Graf wrote:
>>      
>>> We used to use get_free_pages to allocate our vcpu struct. Unfortunately
>>> that call failed on me several times after my machine had a big enough
>>> uptime, as memory became too fragmented by then.
>>>
>>> Fortunately, we don't need it to be page aligned any more! We can just
>>> vmalloc it and everything's great.
>>>
>>>        
>> Applied, thanks.
>>
>> We have the same problem in x86 (though never observed it in practice); my plan there is to split the various structure so they take less than a page.
>>      
> That was my original idea too, but then I looked over the code again and realized that I never need to access the vcpu struct from critical sections, as we moved everything we need there to the PACA.
>
> I also did experience it several times on PPC. But then again, I'm fairly sure the Book3S vcpu struct is a _lot_ larger than the average x86 vcpu struct ;-). I'd need to actually measure it up, but I'm pretty sure it's>  64k.
>    

Right, x86 is around 8k, which is the thread stack size, and if we can't 
allocate that we're really dead.

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