[PATCH v5 12/29] kbuild: lto: limit inlining
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2020-10-09 16:14:23
Also in:
linux-arch, linux-kbuild, linux-pci, lkml
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
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 <redacted> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <redacted> --- Makefile | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/Makefile b/Makefile
index 6d31a78d79ce..3fe2dca17261 100644
--- a/Makefile
+++ b/Makefile@@ -894,6 +894,9 @@ else CC_FLAGS_LTO += -flto endif CC_FLAGS_LTO += -fvisibility=default + +# Limit inlining across translation units to reduce binary size +KBUILD_LDFLAGS += -mllvm -import-instr-limit=5 endif ifdef CONFIG_LTO
--
2.28.0.1011.ga647a8990f-goog
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel