* 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? BTW, I think what matters most is the .text section size, while 'size' would also add exceptions/out-of-line sections too. Here's a way to display the .text section only: triton:~/tip> printf "# vmlinux .text size: %d\n" 0x$(echo $(readelf -W -e vmlinux | grep ' \[ 1\] .text ') | cut -d' ' -f7) # vmlinux .text size: 9797610 triton:~/tip> size vmlinux text data bss dec hex filename 10748306 4875500 876544 16500350 fbc67e vmlinux Thanks, Ingo -- 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>
