On Wed, Jun 13, 2018 at 08:35:46PM +0000, Dave Hansen wrote: > On 06/13/2018 01:31 PM, Kirill A. Shutemov wrote: > >> What actually happens without this patch in place? > > > > One of processes would get the page mapped with wrong KeyID and see > > garbage. > > OK, but what about two pages with the same KeyID? It's actually totally > possible for KSM to determine that two pages have the same plaintext and > merge them. Why don't we do that?
That's exactly what we do :) > > We setup mapping according to KeyID in vma->vm_page_prot. > > Then why do we bother with page_keyid() and the page_ext stuff? VMA is not always around. Using KeyID in vma->vm_page_prot we don't need to change anything in PTE setup functions. It just works. -- Kirill A. Shutemov
