On Thu, May 12 2022 at 21:31, Thomas Gleixner wrote: > On Thu, May 12 2022 at 19:56, Kirill A. Shutemov wrote: >> On Thu, May 12, 2022 at 05:42:58PM +0200, Thomas Gleixner wrote: >>> On Wed, May 11 2022 at 08:49, Peter Zijlstra wrote: >>> > On Wed, May 11, 2022 at 05:27:40AM +0300, Kirill A. Shutemov wrote: >>> > So aren't we creating a problem with LAM_U48 where programs relying on >>> > it are of limited sustainability? >>> > >>> > Any such program simply *cannot* run on 5 level pagetables. Why do we >>> > want to do this? >>> >>> More bits are better :) >>> >>> Seriously, I agree that restricting it to LAM57, which gives us 6 bits, >>> makes a lot of sense _and_ makes the whole thing way simpler. >>> >>> So supporting both needs a truly good justification and a real world use >>> case. >> >> I asked the question before[1]. Basically, more bits more better: >> >> For HWASAN #bits == detection probability. >> For MarkUS #bits == exponential cost reduction > > What is MarkUS? It's not really helpful to provide acronyms which are > not decodable. > >> I would really like to have only LAM_U57, but IIUC 6 bits is not always >> enough. >> >> Dmitry, could you elaborate? >> >> [1] https://mobile.twitter.com/dvyukov/status/1342019823400837120 > > I don't know whether he reacts on posting a link to his twitter > account. I've CC'ed him now. Maybe that works better. Duh. I should have looked at 'To:' and not only at 'Cc:' Maybe someday I get used to this email thing. Thanks, tglx
