From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kees Cook <keescook@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v8 04/16] kbuild: lto: limit inlining
Date: Tue, 1 Dec 2020 13:36:55 -0800 [thread overview]
Message-ID: <20201201213707.541432-5-samitolvanen@google.com> (raw)
In-Reply-To: <20201201213707.541432-1-samitolvanen@google.com>
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>
---
Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Makefile b/Makefile
index 222ae96d179d..ac836907d8b1 100644
--- a/Makefile
+++ b/Makefile
@@ -899,6 +899,9 @@ 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
--
2.29.2.576.ga3fc446d84-goog
WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>
Cc: linux-arch@vger.kernel.org, Kees Cook <keescook@chromium.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
kernel-hardening@lists.openwall.com,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kbuild@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
clang-built-linux@googlegroups.com,
Sami Tolvanen <samitolvanen@google.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v8 04/16] kbuild: lto: limit inlining
Date: Tue, 1 Dec 2020 13:36:55 -0800 [thread overview]
Message-ID: <20201201213707.541432-5-samitolvanen@google.com> (raw)
In-Reply-To: <20201201213707.541432-1-samitolvanen@google.com>
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>
---
Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Makefile b/Makefile
index 222ae96d179d..ac836907d8b1 100644
--- a/Makefile
+++ b/Makefile
@@ -899,6 +899,9 @@ 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
--
2.29.2.576.ga3fc446d84-goog
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next prev parent reply other threads:[~2020-12-01 21:39 UTC|newest]
Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 21:36 [PATCH v8 00/16] Add support for Clang LTO Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 01/16] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:47 ` Steven Rostedt
2020-12-01 21:47 ` Steven Rostedt
2020-12-01 21:36 ` [PATCH v8 02/16] kbuild: add support for Clang LTO Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-02 2:59 ` Masahiro Yamada
2020-12-02 2:59 ` Masahiro Yamada
2020-12-03 0:07 ` Nick Desaulniers
2020-12-03 0:07 ` Nick Desaulniers
2020-12-03 0:07 ` Nick Desaulniers
2020-12-01 21:36 ` [PATCH v8 03/16] kbuild: lto: fix module versioning Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen [this message]
2020-12-01 21:36 ` [PATCH v8 04/16] kbuild: lto: limit inlining Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 05/16] kbuild: lto: merge module sections Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 06/16] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 07/16] init: lto: ensure initcall ordering Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 08/16] init: lto: fix PREL32 relocations Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 09/16] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 10/16] modpost: lto: strip .lto from module names Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 11/16] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 12/16] efi/libstub: disable LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 13/16] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 14/16] arm64: vdso: disable LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 15/16] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 16/16] arm64: allow LTO to be selected Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-03 0:01 ` [PATCH v8 00/16] Add support for Clang LTO Nick Desaulniers
2020-12-03 0:01 ` Nick Desaulniers
2020-12-03 0:01 ` Nick Desaulniers
2020-12-03 11:26 ` Will Deacon
2020-12-03 11:26 ` Will Deacon
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 18:21 ` Nathan Chancellor
2020-12-03 18:21 ` Nathan Chancellor
2020-12-03 18:22 ` Will Deacon
2020-12-03 18:22 ` Will Deacon
2020-12-03 22:32 ` Nick Desaulniers
2020-12-03 22:32 ` Nick Desaulniers
2020-12-03 22:32 ` Nick Desaulniers
2020-12-04 9:35 ` Will Deacon
2020-12-04 9:35 ` Will Deacon
2020-12-04 22:52 ` Sami Tolvanen
2020-12-04 22:52 ` Sami Tolvanen
2020-12-04 22:52 ` Sami Tolvanen
2020-12-06 6:50 ` Nathan Chancellor
2020-12-06 6:50 ` Nathan Chancellor
2020-12-06 20:09 ` Sami Tolvanen
2020-12-06 20:09 ` Sami Tolvanen
2020-12-06 20:09 ` Sami Tolvanen
2020-12-08 0:46 ` Nathan Chancellor
2020-12-08 0:46 ` Nathan Chancellor
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:56 ` Arnd Bergmann
2020-12-08 16:56 ` Arnd Bergmann
2020-12-08 16:56 ` Arnd Bergmann
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 20:59 ` Arnd Bergmann
2020-12-08 20:59 ` Arnd Bergmann
2020-12-08 21:02 ` Arnd Bergmann
2020-12-08 21:02 ` Arnd Bergmann
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:59 ` Arnd Bergmann
2020-12-09 9:59 ` Arnd Bergmann
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 19:24 ` Arnd Bergmann
2020-12-09 19:24 ` Arnd Bergmann
2020-12-09 19:24 ` Arnd Bergmann
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 22:20 ` Arnd Bergmann
2020-12-08 22:20 ` Arnd Bergmann
2020-12-08 22:20 ` Arnd Bergmann
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 4:55 ` Fangrui Song
2020-12-09 4:55 ` Fangrui Song
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 17:51 ` Arnd Bergmann
2020-12-09 17:51 ` Arnd Bergmann
2020-12-09 17:51 ` Arnd Bergmann
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