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authorPeter Zijlstra <peterz@infradead.org>2013-08-14 14:51:00 +0200
committerIngo Molnar <mingo@kernel.org>2013-09-25 14:23:07 +0200
commit1a338ac32ca630f67df25b4a16436cccc314e997 (patch)
tree3291247c33c17376160821d19d1460c2da1da1a6 /include
parentc2daa3bed53a81171cf8c1a36db798e82b91afe8 (diff)
downloadlinux-1a338ac32ca630f67df25b4a16436cccc314e997.tar.gz
sched, x86: Optimize the preempt_schedule() call
Remove the bloat of the C calling convention out of the
preempt_enable() sites by creating an ASM wrapper which allows us to
do an asm("call ___preempt_schedule") instead.

calling.h bits by Andi Kleen

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org
[ Fixed build error. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/asm-generic/preempt.h10
-rw-r--r--include/linux/preempt.h13
2 files changed, 15 insertions, 8 deletions
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index 82d958fc3823..5dc14ed3791c 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -100,4 +100,14 @@ static __always_inline bool should_resched(void)
 	return unlikely(!*preempt_count_ptr());
 }
 
+#ifdef CONFIG_PREEMPT
+extern asmlinkage void preempt_schedule(void);
+#define __preempt_schedule() preempt_schedule()
+
+#ifdef CONFIG_CONTEXT_TRACKING
+extern asmlinkage void preempt_schedule_context(void);
+#define __preempt_schedule_context() preempt_schedule_context()
+#endif
+#endif /* CONFIG_PREEMPT */
+
 #endif /* __ASM_PREEMPT_H */
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 2343d8715299..a3d9dc8c2c00 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -50,18 +50,17 @@ do { \
 #define preempt_enable_no_resched() sched_preempt_enable_no_resched()
 
 #ifdef CONFIG_PREEMPT
-asmlinkage void preempt_schedule(void);
 #define preempt_enable() \
 do { \
 	barrier(); \
 	if (unlikely(preempt_count_dec_and_test())) \
-		preempt_schedule(); \
+		__preempt_schedule(); \
 } while (0)
 
 #define preempt_check_resched() \
 do { \
 	if (should_resched()) \
-		preempt_schedule(); \
+		__preempt_schedule(); \
 } while (0)
 
 #else
@@ -83,17 +82,15 @@ do { \
 
 #ifdef CONFIG_PREEMPT
 
-#ifdef CONFIG_CONTEXT_TRACKING
-asmlinkage void preempt_schedule_context(void);
-#else
-#define preempt_schedule_context() preempt_schedule()
+#ifndef CONFIG_CONTEXT_TRACKING
+#define __preempt_schedule_context() __preempt_schedule()
 #endif
 
 #define preempt_enable_notrace() \
 do { \
 	barrier(); \
 	if (unlikely(__preempt_count_dec_and_test())) \
-		preempt_schedule_context(); \
+		__preempt_schedule_context(); \
 } while (0)
 #else
 #define preempt_enable_notrace() preempt_enable_no_resched_notrace()