4 files changed, 35 insertions, 8 deletions

diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index a03e9398a6c2..14f7494280f0 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -23,3 +23,21 @@
  * code
  */
 #define uninitialized_var(x) x = x
+
+#if !(__GNUC__ == 4 && __GNUC_MINOR__ < 3)
+/* Mark functions as cold. gcc will assume any path leading to a call
+   to them will be unlikely.  This means a lot of manual unlikely()s
+   are unnecessary now for any paths leading to the usual suspects
+   like BUG(), printk(), panic() etc. [but let's keep them for now for
+   older compilers]
+
+   Early snapshots of gcc 4.3 don't support this and we can't detect this
+   in the preprocessor, but we can live with this because they're unreleased.
+   Maketime probing would be overkill here.
+
+   gcc also has a __attribute__((__hot__)) to move hot functions into
+   a special section, but I don't see any sense in this right now in
+   the kernel context */
+#define __cold                  __attribute__((__cold__))
+
+#endif
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 8287a72bb6a9..12a1291855e2 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -174,4 +174,13 @@ extern void __chk_io_ptr(const void __iomem *);
 # define __attribute_const__    /* unimplemented */
 #endif
 
+/*
+ * Tell gcc if a function is cold. The compiler will assume any path
+ * directly leading to the call is unlikely.
+ */
+
+#ifndef __cold
+#define __cold
+#endif
+
 #endif /* __LINUX_COMPILER_H */
diff --git a/include/linux/init.h b/include/linux/init.h
index 5b5285316339..f0d0e3295a9b 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -40,10 +40,10 @@
 
 /* These are for everybody (although not all archs will actually
    discard it in modules) */
-#define __init          __attribute__ ((__section__ (".init.text")))
+#define __init          __attribute__ ((__section__ (".init.text"))) __cold
 #define __initdata      __attribute__ ((__section__ (".init.data")))
 #define __exitdata      __attribute__ ((__section__(".exit.data")))
-#define __exit_call     __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
+#define __exit_call     __attribute_used__ __attribute__ ((__section__ (".exitcall.exit"))) __cold
 
 /* modpost check for section mismatches during the kernel build.
  * A section mismatch happens when there are references from a
@@ -59,9 +59,9 @@
 #define __initdata_refok          __attribute__ ((__section__ (".data.init.refok")))
 
 #ifdef MODULE
-#define __exit          __attribute__ ((__section__(".exit.text")))
+#define __exit          __attribute__ ((__section__(".exit.text"))) __cold
 #else
-#define __exit          __attribute_used__ __attribute__ ((__section__(".exit.text")))
+#define __exit          __attribute_used__ __attribute__ ((__section__(".exit.text"))) __cold
 #endif
 
 /* For assembly routines */
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 1eb9cde550c4..4300bb462d29 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -106,7 +106,7 @@ extern int cond_resched(void);
 extern struct atomic_notifier_head panic_notifier_list;
 extern long (*panic_blink)(long time);
 NORET_TYPE void panic(const char * fmt, ...)
-        __attribute__ ((NORET_AND format (printf, 1, 2)));
+        __attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
 extern void oops_enter(void);
 extern void oops_exit(void);
 extern int oops_may_print(void);
@@ -155,14 +155,14 @@ extern void dump_thread(struct pt_regs *regs, struct user *dump);
 asmlinkage int vprintk(const char *fmt, va_list args)
         __attribute__ ((format (printf, 1, 0)));
 asmlinkage int printk(const char * fmt, ...)
-        __attribute__ ((format (printf, 1, 2)));
+        __attribute__ ((format (printf, 1, 2))) __cold;
 #else
 static inline int vprintk(const char *s, va_list args)
         __attribute__ ((format (printf, 1, 0)));
 static inline int vprintk(const char *s, va_list args) { return 0; }
 static inline int printk(const char *s, ...)
         __attribute__ ((format (printf, 1, 2)));
-static inline int printk(const char *s, ...) { return 0; }
+static inline int __cold printk(const char *s, ...) { return 0; }
 #endif
 
 unsigned long int_sqrt(unsigned long);
@@ -212,7 +212,7 @@ extern enum system_states {
 #define TAINT_USER                      (1<<6)
 #define TAINT_DIE                       (1<<7)
 
-extern void dump_stack(void);
+extern void dump_stack(void) __cold;
 
 enum {
         DUMP_PREFIX_NONE,