Re: [PATCH v2 12/28] kbuild: lto: limit inlining

From: Kees Cook
Date: Thu Sep 03 2020 - 18:20:24 EST


On Thu, Sep 03, 2020 at 01:30:37PM -0700, Sami Tolvanen wrote:
> This change limits function inlining across translation unit boundaries
> in order to reduce the binary size with LTO. The -import-instr-limit
> flag defines a size limit, as the number of LLVM IR instructions, for
> importing functions from other TUs, defaulting to 100.
>
> Based on testing with arm64 defconfig, we found that a limit of 5 is a
> reasonable compromise between performance and binary size, reducing the
> size of a stripped vmlinux by 11%.
>
> Suggested-by: George Burgess IV <gbiv@xxxxxxxxxx>
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook