On Thu, May 25, 2017 at 1:33 PM, Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > Here' my first attempt to bring boot-time between 4- and 5-level paging. > It looks not too terrible to me. I've expected it to be worse. If I read this right, you just made it a global on/off thing. May I suggest possibly a different model entirely? Can you make it a per-mm flag instead? And then we (a) make all kthreads use the 4-level page tables (b) which means that all the init code uses the 4-level page tables (c) which means that all those checks for "start_secondary" etc can just go away, because those all run with 4-level page tables. Or is it just much too expensive to switch between 4-level and 5-level paging at run-time? Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>