The patch titled
Subject: compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING
has been added to the -mm tree. Its filename is
compiler-allow-all-arches-to-enable-config_optimize_inlining.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/compiler-allow-all-arches-to-enable-config_optimize_inlining.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/compiler-allow-all-arches-to-enable-config_optimize_inlining.patch
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------------------------------------------------------
From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Subject: compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING
60a3cdd06394 ("x86: add optimized inlining") introduced
CONFIG_OPTIMIZE_INLINING, but it has been available only for x86.
The idea is obviously arch-agnostic. This commit moves the config entry
from arch/x86/Kconfig.debug to lib/Kconfig.debug so that all architectures
can benefit from it.
This can make a huge difference in kernel image size especially when
CONFIG_OPTIMIZE_FOR_SIZE is enabled.
For example, I got 3.5% smaller arm64 kernel for v5.1-rc1.
dec file
18983424 arch/arm64/boot/Image.before
18321920 arch/arm64/boot/Image.after
This also slightly improves the "Kernel hacking" Kconfig menu as
e61aca5158a8 ("Merge branch 'kconfig-diet' from Dave Hansen') suggested;
this config option would be a good fit in the "compiler option" menu.
Link: http://lkml.kernel.org/r/20190423034959.13525-12-yamada.masahiro@xxxxxxxxxxxxx
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/Kconfig | 3 ---
arch/x86/Kconfig.debug | 14 --------------
include/linux/compiler_types.h | 3 +--
lib/Kconfig.debug | 14 ++++++++++++++
4 files changed, 15 insertions(+), 19 deletions(-)
--- a/arch/x86/Kconfig~compiler-allow-all-arches-to-enable-config_optimize_inlining
+++ a/arch/x86/Kconfig
@@ -309,9 +309,6 @@ config ZONE_DMA32
config AUDIT_ARCH
def_bool y if X86_64
-config ARCH_SUPPORTS_OPTIMIZED_INLINING
- def_bool y
-
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
def_bool y
--- a/arch/x86/Kconfig.debug~compiler-allow-all-arches-to-enable-config_optimize_inlining
+++ a/arch/x86/Kconfig.debug
@@ -266,20 +266,6 @@ config CPA_DEBUG
---help---
Do change_page_attr() self-tests every 30 seconds.
-config OPTIMIZE_INLINING
- bool "Allow gcc to uninline functions marked 'inline'"
- ---help---
- This option determines if the kernel forces gcc to inline the functions
- developers have marked 'inline'. Doing so takes away freedom from gcc to
- do what it thinks is best, which is desirable for the gcc 3.x series of
- compilers. The gcc 4.x series have a rewritten inlining algorithm and
- enabling this option will generate a smaller kernel there. Hopefully
- this algorithm is so good that allowing gcc 4.x and above to make the
- decision will become the default in the future. Until then this option
- is there to test gcc for this.
-
- If unsure, say N.
-
config DEBUG_ENTRY
bool "Debug low-level entry code"
depends on DEBUG_KERNEL
--- a/include/linux/compiler_types.h~compiler-allow-all-arches-to-enable-config_optimize_inlining
+++ a/include/linux/compiler_types.h
@@ -140,8 +140,7 @@ struct ftrace_likely_data {
* Do not use __always_inline here, since currently it expands to inline again
* (which would break users of __always_inline).
*/
-#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
- !defined(CONFIG_OPTIMIZE_INLINING)
+#if !defined(CONFIG_OPTIMIZE_INLINING)
#define inline inline __attribute__((__always_inline__)) __gnu_inline \
__maybe_unused notrace
#else
--- a/lib/Kconfig.debug~compiler-allow-all-arches-to-enable-config_optimize_inlining
+++ a/lib/Kconfig.debug
@@ -310,6 +310,20 @@ config HEADERS_CHECK
exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
your build tree), to make sure they're suitable.
+config OPTIMIZE_INLINING
+ bool "Allow compiler to uninline functions marked 'inline'"
+ help
+ This option determines if the kernel forces gcc to inline the functions
+ developers have marked 'inline'. Doing so takes away freedom from gcc to
+ do what it thinks is best, which is desirable for the gcc 3.x series of
+ compilers. The gcc 4.x series have a rewritten inlining algorithm and
+ enabling this option will generate a smaller kernel there. Hopefully
+ this algorithm is so good that allowing gcc 4.x and above to make the
+ decision will become the default in the future. Until then this option
+ is there to test gcc for this.
+
+ If unsure, say N.
+
config DEBUG_SECTION_MISMATCH
bool "Enable full Section mismatch analysis"
help
_
Patches currently in -mm which might be from yamada.masahiro@xxxxxxxxxxxxx are
remove-spdx-with-linux-syscall-note-from-kernel-space-headers.patch
arm64-mark-__cpus_have_const_cap-as-__always_inline.patch
mips-mark-mult_sh_align_mod-as-__always_inline.patch
s390-cpacf-mark-scpacf_query-as-__always_inline.patch
mtd-rawnand-vf610_nfc-add-initializer-to-avoid-wmaybe-uninitialized.patch
mips-mark-__fls-and-__ffs-as-__always_inline.patch
arm-mark-setup_machine_tags-stub-as-__init-__noreturn.patch
powerpc-prom_init-mark-prom_getprop-and-prom_getproplen-as-__init.patch
powerpc-mm-radix-mark-__radix__flush_tlb_range_psize-as-__always_inline.patch
powerpc-mm-radix-mark-as-__tlbie_pid-and-friends-as__always_inline.patch
compiler-allow-all-arches-to-enable-config_optimize_inlining.patch
treewide-replace-include-asm-sizesh-with-include-linux-sizesh.patch
arch-remove-asm-sizesh-amd-asm-generic-sizesh.patch
