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authorIngo Molnar <mingo@elte.hu>2008-03-03 12:38:52 +0100
committerIngo Molnar <mingo@elte.hu>2008-04-26 17:44:55 +0200
commit60a3cdd0639473c79c253bc08c8ef8f882cca107 (patch)
treee72a5ca87873b286b02966a390277f828139d350 /include
parentb1721d0da266b4af8cb4419473b4ca36206ab200 (diff)
x86: add optimized inlining
add CONFIG_OPTIMIZE_INLINING=y. allow gcc to optimize the kernel image's size by uninlining functions that have been marked 'inline'. Previously gcc was forced by Linux to always-inline these functions via a gcc attribute: #define inline inline __attribute__((always_inline)) Especially when the user has already selected CONFIG_OPTIMIZE_FOR_SIZE=y this can make a huge difference in kernel image size (using a standard Fedora .config): text data bss dec hex filename 5613924 562708 3854336 10030968 990f78 vmlinux.before 5486689 562708 3854336 9903733 971e75 vmlinux.after that's a 2.3% text size reduction (!). Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
-rw-r--r--include/linux/compiler-gcc.h12
1 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index fe23792f05c1..340bc5d92772 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -28,9 +28,15 @@
#define __must_be_array(a) \
BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
-#define inline inline __attribute__((always_inline))
-#define __inline__ __inline__ __attribute__((always_inline))
-#define __inline __inline __attribute__((always_inline))
+/*
+ * Force always-inline if the user requests it so via the .config:
+ */
+#if !defined(CONFIG_OPTIMIZE_INLINING) && (__GNUC__ >= 4)
+# define inline inline __attribute__((always_inline))
+# define __inline__ __inline__ __attribute__((always_inline))
+# define __inline __inline __attribute__((always_inline))
+#endif
+
#define __deprecated __attribute__((deprecated))
#define __packed __attribute__((packed))
#define __weak __attribute__((weak))