From a9df3d0f312f4b1aefec76ae5ee86cccbf7cd4e0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 14 Jan 2006 13:21:33 -0800 Subject: [PATCH] [PATCH] When CONFIG_CC_OPTIMIZE_FOR_SIZE, allow gcc4 to control inlining If optimizing for size (CONFIG_CC_OPTIMIZE_FOR_SIZE), allow gcc4 compilers to decide what to inline and what not - instead of the kernel forcing gcc to inline all the time. This requires several places that require to be inlined to be marked as such, previous patches in this series do that. Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/feature-removal-schedule.txt | 9 +++++++++ include/linux/compiler-gcc4.h | 9 +++++++++ lib/Kconfig.debug | 14 ++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 9474501..b4a1ea7 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -123,6 +123,15 @@ Who: Christoph Hellwig --------------------------- +What: CONFIG_FORCED_INLINING +When: June 2006 +Why: Config option is there to see if gcc is good enough. (in january + 2006). If it is, the behavior should just be the default. If it's not, + the option should just go away entirely. +Who: Arjan van de Ven + +--------------------------- + What: START_ARRAY ioctl for md When: July 2006 Files: drivers/md/md.c diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 8249115..6f5cc6f 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -3,6 +3,15 @@ /* These definitions are for GCC v4.x. */ #include +#ifdef CONFIG_FORCED_INLINING +# undef inline +# undef __inline__ +# undef __inline +# define inline inline __attribute__((always_inline)) +# define __inline__ __inline__ __attribute__((always_inline)) +# define __inline __inline __attribute__((always_inline)) +#endif + #define __attribute_used__ __attribute__((__used__)) #define __must_check __attribute__((warn_unused_result)) #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a609235..a314e66 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -195,6 +195,20 @@ config FRAME_POINTER some architectures or if you use external debuggers. If you don't debug the kernel, you can say N. +config FORCED_INLINING + bool "Force gcc to inline functions marked 'inline'" + depends on DEBUG_KERNEL + default y + 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 + disabling this option will generate a smaller kernel there. Hopefully + this algorithm is so good that allowing gcc4 to make the decision can + become the default in the future, until then this option is there to + test gcc for this. + config RCU_TORTURE_TEST tristate "torture tests for RCU" depends on DEBUG_KERNEL -- 2.7.4