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    Subject[PATCH 06/22] kbuild: lto: limit inlining
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    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.
    The default value is 100, and decreasing it to 5 reduces the size
    of a stripped arm64 defconfig vmlinux by 11%.

    Suggested-by: George Burgess IV <gbiv@google.com>
    Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
    ---
    Makefile | 4 ++++
    1 file changed, 4 insertions(+)

    diff --git a/Makefile b/Makefile
    index 3a7e5e5c17b9..ee66513a5b66 100644
    --- a/Makefile
    +++ b/Makefile
    @@ -894,6 +894,10 @@ else
    CC_FLAGS_LTO_CLANG := -flto
    endif
    CC_FLAGS_LTO_CLANG += -fvisibility=default
    +
    +# Limit inlining across translation units to reduce binary size
    +LD_FLAGS_LTO_CLANG := -mllvm -import-instr-limit=5
    +KBUILD_LDFLAGS += $(LD_FLAGS_LTO_CLANG)
    endif

    ifdef CONFIG_LTO
    --
    2.27.0.212.ge8ba1cc988-goog
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