Messages in this thread | | | Date | Wed, 10 Apr 2019 09:31:40 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 08/10] x86-64: select DYNAMIC_DEBUG_RELATIVE_POINTERS |
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* Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:
> This reduces the size of struct _ddebug from 56 to 40 bytes. There's > one such struct for each pr_debug(), netdev_debug() etc. in a > CONFIG_DYNAMIC_DEBUG kernel. An Ubuntu 4.15 kernel has about 2550 > entries in the __verbose section of vmlinux, amounting to ~40K > saved. (Modules also become smaller, but it's harder to quantify how > much that yields at runtime.) > > For comparison, the __bug_table section of that Ubuntu kernel is 75576 > bytes, i.e. 6298 12-byte bug_entrys, so GENERIC_BUG_RELATIVE_POINTERS > saves ~50K. > > Due to the build-time sanity checks in asm-generic/dynamic_debug.h, we > need to add another #undef to vclock_gettime.c. > > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > --- > arch/x86/Kconfig | 1 + > arch/x86/entry/vdso/vdso32/vclock_gettime.c | 1 + > arch/x86/include/asm/Kbuild | 1 + > 3 files changed, 3 insertions(+) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 5ad92419be19..eb5488b4577d 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -30,6 +30,7 @@ config X86_64 > select SWIOTLB > select X86_DEV_DMA_OPS > select ARCH_HAS_SYSCALL_WRAPPER > + select DYNAMIC_DEBUG_RELATIVE_POINTERS
Acked-by: Ingo Molnar <mingo@kernel.org>
Thanks,
Ingo
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