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 <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
[ Fixed build error. ]
Signed-off-by: Ingo Molnar <[email protected]>
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 2343d87..a3d9dc8 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -50,18 +50,17 @@
#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 @@
#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()
