On Mon, Jul 16, 2018 at 01:05:24AM +0000, Dou Liyang wrote: > Dear Kirill, > > Sorry to trouble you. > > I am trying to make the Crash can parse the kernel with 5-level paging. > > I met a problem, seek help. > > IMO, all user-sapce tasks must using 5-level paging if the kernel > has been in 5-level paging decided by '__pgtable_l5_enabled=1'. Correct? There's no way to enable paging mode on per-task basis. It's enabled with flag in CR4 therefore it's global. > And, In the Documentation/x86/x86_64/5level-paging.txt: > > ... > To mitigate this, we are not going to allocate virtual address space > above 47-bit by default. > > But userspace can ask for allocation from full address space by > specifying hint address (with or without MAP_FIXED) above 47-bits. > ... > > I guess it just means that some user-space tasks can't using the address > above 47-bits, it doesn't mean that the tasks will back to use 4-level > paging if the kernel has been in 5-level paging. Is it right? Right. -- Kirill A. Shutemov -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
