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

[Takuya Yoshikawa <takuya.yoshikawa@gmail.com>]

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.

Thanks,
	Takuya