Re: [PATCH] KVM: Avoid wasting pages for small lpage_info arrays

[Avi Kivity <avi@redhat.com>]

On 05/14/2012 04:29 PM, Takuya Yoshikawa wrote:
> On Sun, 13 May 2012 13:20:46 +0300
> Avi Kivity <avi@redhat.com> wrote:
>
> > I don't feel that the savings is worth the extra complication.  We save
> > two pages per memslot here.
>
> Using a 4KB vmalloced page for a 16B array is ...
>
> Actually I felt like you before and did not do this, but recently there
> was a talk about creating hundreds of memslots.
>
> > What about using kvmalloc() instead of vmalloc()?  It's in
> > security/apparmor now, but can be made generic.
>
> Andrew once, maybe some times, rejected making such an API generic saying
> that there should not be a generic criterion by which we can decide which
> function - vmalloc() or kmalloc() - to use.
>
> So each caller should decide by its own criteria.
>
> In this case, we need to implement kvm specific kvmalloc().
> BTW, we are already doing this for dirty_bitmap.

Okay, a local kvmalloc() is better than open-coding the logic.

Andrew, prepare yourself for some code duplication.

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