Re: [RFC][PATCH 3/6] mm: VMA sequence count

From: Kirill A. Shutemov
Date: Thu Oct 23 2014 - 08:39:38 EST


On Wed, Oct 22, 2014 at 03:44:16PM +0200, Peter Zijlstra wrote:
> On Wed, Oct 22, 2014 at 02:15:54PM +0200, Peter Zijlstra wrote:
> > On Wed, Oct 22, 2014 at 02:53:04PM +0300, Kirill A. Shutemov wrote:
> > > Em, no. In this case change_protection() will not touch the pte, since
> > > it's pte_none() and the pte_same() check will pass just fine.
> >
> > Oh, that's what you meant. Yes that's a problem, yes vm_page_prot
> > needs wrapping too.
>
> Maybe also vm_policy, is there anything else that can change while a vma
> lives?

- vm_flags, obviously;
- shared, anon_vma and anon_vma_chain (at least on the first write fault
to private mapping);
- vm_pgoff (mremap(2) ?);
- vm_private_data -- it's all over drivers. Potential nightmare, but
seems not in use for anon mappings.

--
Kirill A. Shutemov
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/