On Thu, Oct 12, 2023 at 10:53 PM Dave Hansen <[email protected]> wrote: > > On 10/12/23 13:12, Uros Bizjak wrote: > > The last patch introduces (%rip) suffix and uses it for x86_64 target, > > resulting in a small code size decrease: text data bss dec hex filename > > 25510677 4386685 808388 30705750 1d48856 vmlinux-new.o 25510629 4386685 > > 808388 30705702 1d48826 vmlinux-old.o > > I feel like I'm missing some of the motivation here. > > 50 bytes is great and all, but it isn't without the cost of changing > some rules and introducing potential PER_CPU_ARG() vs. PER_CPU_VAR() > confusion. > > Are there some other side benefits? What else does this enable?
These changes are necessary to build the kernel as Position Independent Executable (PIE) on x86_64 [1]. And since I was working in percpu area I thought that it was worth implementing them. [1] https://lore.kernel.org/lkml/[email protected]/ Uros.
