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. Thanks, tglx
