On Wed, Apr 27, 2016 at 05:57:30PM +0200, Andrea Arcangeli wrote:
> couldn't do a fix as cleaner as this one for 4.6.
ehm "cleaner then"
If you've suggestions for a better name than PageTransCompoundMap I
can respin a new patch though, I considered "CanMap" but I opted for
the short version.
Als
On Wed, Apr 27, 2016 at 06:18:34PM +0300, Kirill A. Shutemov wrote:
> Okay, I see.
>
> But do we really want to make PageTransCompoundMap() visiable beyond KVM
> code? It looks like too KVM-specific.
Any other secondary MMU notifier manager (KVM is just one of the many
MMU notifier users) will ne
On Wed, Apr 27, 2016 at 04:59:57PM +0200, Andrea Arcangeli wrote:
> On Wed, Apr 27, 2016 at 04:50:30PM +0300, Kirill A. Shutemov wrote:
> > I know nothing about kvm. How do you protect against pmd splitting between
> > get_user_pages() and the check?
>
> get_user_pages_fast() runs fully lockless a
On Wed, Apr 27, 2016 at 04:50:30PM +0300, Kirill A. Shutemov wrote:
> I know nothing about kvm. How do you protect against pmd splitting between
> get_user_pages() and the check?
get_user_pages_fast() runs fully lockless and unpins the page right
away (we need a get_user_pages_fast without the FOL
On Wed, Apr 27, 2016 at 02:04:46PM +0200, Andrea Arcangeli wrote:
> After the THP refcounting change, obtaining a compound pages from
> get_user_pages() no longer allows us to assume the entire compound
> page is immediately mappable from a secondary MMU.
>
> A secondary MMU doesn't want to call g
After the THP refcounting change, obtaining a compound pages from
get_user_pages() no longer allows us to assume the entire compound
page is immediately mappable from a secondary MMU.
A secondary MMU doesn't want to call get_user_pages() more than once
for each compound page, in order to know if i
