On Thu, Aug 17, 2017 at 01:10:05PM +0200, Ingo Molnar wrote: > > * Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > > > On Thu, Aug 17, 2017 at 11:00:38AM +0200, Ingo Molnar wrote: > > > > > > * Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > > > > > > > For boot-time switching between 4- and 5-level paging we need to be able > > > > to fold p4d page table level at runtime. It requires variable > > > > PGDIR_SHIFT and PTRS_PER_P4D. > > > > > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > > > --- > > > > arch/x86/boot/compressed/kaslr.c | 5 +++++ > > > > arch/x86/include/asm/pgtable_32.h | 2 ++ > > > > arch/x86/include/asm/pgtable_32_types.h | 2 ++ > > > > arch/x86/include/asm/pgtable_64_types.h | 15 +++++++++++++-- > > > > arch/x86/kernel/head64.c | 9 ++++++++- > > > > arch/x86/mm/dump_pagetables.c | 12 +++++------- > > > > arch/x86/mm/init_64.c | 2 +- > > > > arch/x86/mm/kasan_init_64.c | 2 +- > > > > arch/x86/platform/efi/efi_64.c | 4 ++-- > > > > include/asm-generic/5level-fixup.h | 1 + > > > > include/asm-generic/pgtable-nop4d.h | 1 + > > > > include/linux/kasan.h | 2 +- > > > > mm/kasan/kasan_init.c | 2 +- > > > > 13 files changed, 43 insertions(+), 16 deletions(-) > > > > > > So I'm wondering what the code generation effect of this is - what's the > > > before/after vmlinux size? > > > > > > My guess is that the effect should be very small, as these constants are not > > > widely used - but I'm only guessing and could be wrong. > > > > This change increase vmlinux size for defconfig + X86_5LEVEL=y by ~4k or > > 0.01%. > > Please add this info to one of the changelogs. > > BTW., some of that might be won back via the later optimizations, right? Sorry, but no. Just chacked. Introducing alternatives increases .text segment size by about 4k. -- Kirill A. Shutemov -- 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>
