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| author | Sami Tolvanen <samitolvanen@google.com> | 2020-12-11 10:46:21 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2021-01-14 08:21:08 -0800 |
| commit | 22d429e75f24d114d99223389d6ba7047e952e32 (patch) | |
| tree | 489a21731b2b0c690c0f5452e99c965d3097e266 /Makefile | |
| parent | 38e89184900385b0dad1ee55c35ae8abcfee6ece (diff) | |
| download | lwn-22d429e75f24d114d99223389d6ba7047e952e32.tar.gz lwn-22d429e75f24d114d99223389d6ba7047e952e32.zip | |
kbuild: lto: limit inlining
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@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-5-samitolvanen@google.com
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -901,6 +901,9 @@ else CC_FLAGS_LTO += -flto endif CC_FLAGS_LTO += -fvisibility=hidden + +# Limit inlining across translation units to reduce binary size +KBUILD_LDFLAGS += -mllvm -import-instr-limit=5 endif ifdef CONFIG_LTO |