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authorFrederic Weisbecker <fweisbec@gmail.com>2015-06-04 17:39:08 +0200
committerIngo Molnar <mingo@kernel.org>2015-06-07 15:57:42 +0200
commit4eaca0a887eaee04fc7a3866d0f5b51b34030dfa (patch)
tree82ebaa639373c69aad063040cb87228fe5a0645c
parentsched: Make preempt_schedule_context() function-tracing safe (diff)
downloadlinux-4eaca0a887eaee04fc7a3866d0f5b51b34030dfa.tar.xz
linux-4eaca0a887eaee04fc7a3866d0f5b51b34030dfa.zip
preempt: Use preempt_schedule_context() as the official tracing preemption point
preempt_schedule_context() is a tracing safe preemption point but it's only used when CONFIG_CONTEXT_TRACKING=y. Other configs have tracing recursion issues since commit: b30f0e3ffedf ("sched/preempt: Optimize preemption operations on __schedule() callers") introduced function based preemp_count_*() ops. Lets make it available on all configs and give it a more appropriate name for its new position. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433432349-1021-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/include/asm/preempt.h8
-rw-r--r--arch/x86/kernel/i386_ksyms_32.c4
-rw-r--r--arch/x86/kernel/x8664_ksyms_64.c4
-rw-r--r--arch/x86/lib/thunk_32.S4
-rw-r--r--arch/x86/lib/thunk_64.S4
-rw-r--r--include/asm-generic/preempt.h7
-rw-r--r--include/linux/preempt.h6
-rw-r--r--kernel/sched/core.c8
8 files changed, 13 insertions, 32 deletions
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 8f3271842533..dca71714f860 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -99,11 +99,9 @@ static __always_inline bool should_resched(void)
extern asmlinkage void ___preempt_schedule(void);
# define __preempt_schedule() asm ("call ___preempt_schedule")
extern asmlinkage void preempt_schedule(void);
-# ifdef CONFIG_CONTEXT_TRACKING
- extern asmlinkage void ___preempt_schedule_context(void);
-# define __preempt_schedule_context() asm ("call ___preempt_schedule_context")
- extern asmlinkage void preempt_schedule_context(void);
-# endif
+ extern asmlinkage void ___preempt_schedule_notrace(void);
+# define __preempt_schedule_notrace() asm ("call ___preempt_schedule_notrace")
+ extern asmlinkage void preempt_schedule_notrace(void);
#endif
#endif /* __ASM_PREEMPT_H */
diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c
index 05fd74f537d6..64341aa485ae 100644
--- a/arch/x86/kernel/i386_ksyms_32.c
+++ b/arch/x86/kernel/i386_ksyms_32.c
@@ -40,7 +40,5 @@ EXPORT_SYMBOL(empty_zero_page);
#ifdef CONFIG_PREEMPT
EXPORT_SYMBOL(___preempt_schedule);
-#ifdef CONFIG_CONTEXT_TRACKING
-EXPORT_SYMBOL(___preempt_schedule_context);
-#endif
+EXPORT_SYMBOL(___preempt_schedule_notrace);
#endif
diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c
index 37d8fa4438f0..a0695be19864 100644
--- a/arch/x86/kernel/x8664_ksyms_64.c
+++ b/arch/x86/kernel/x8664_ksyms_64.c
@@ -75,7 +75,5 @@ EXPORT_SYMBOL(native_load_gs_index);
#ifdef CONFIG_PREEMPT
EXPORT_SYMBOL(___preempt_schedule);
-#ifdef CONFIG_CONTEXT_TRACKING
-EXPORT_SYMBOL(___preempt_schedule_context);
-#endif
+EXPORT_SYMBOL(___preempt_schedule_notrace);
#endif
diff --git a/arch/x86/lib/thunk_32.S b/arch/x86/lib/thunk_32.S
index 5eb715087b80..e407941d0488 100644
--- a/arch/x86/lib/thunk_32.S
+++ b/arch/x86/lib/thunk_32.S
@@ -38,8 +38,6 @@
#ifdef CONFIG_PREEMPT
THUNK ___preempt_schedule, preempt_schedule
-#ifdef CONFIG_CONTEXT_TRACKING
- THUNK ___preempt_schedule_context, preempt_schedule_context
-#endif
+ THUNK ___preempt_schedule_notrace, preempt_schedule_notrace
#endif
diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S
index f89ba4e93025..2198902329b5 100644
--- a/arch/x86/lib/thunk_64.S
+++ b/arch/x86/lib/thunk_64.S
@@ -49,9 +49,7 @@
#ifdef CONFIG_PREEMPT
THUNK ___preempt_schedule, preempt_schedule
-#ifdef CONFIG_CONTEXT_TRACKING
- THUNK ___preempt_schedule_context, preempt_schedule_context
-#endif
+ THUNK ___preempt_schedule_notrace, preempt_schedule_notrace
#endif
#if defined(CONFIG_TRACE_IRQFLAGS) \
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index eb6f9e6c3075..d0a7a4753db2 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -79,11 +79,8 @@ static __always_inline bool should_resched(void)
#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
+extern asmlinkage void preempt_schedule_notrace(void);
+#define __preempt_schedule_notrace() preempt_schedule_notrace()
#endif /* CONFIG_PREEMPT */
#endif /* __ASM_PREEMPT_H */
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index a1a00e14c14f..7686dd63bc35 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -204,15 +204,11 @@ do { \
#ifdef CONFIG_PREEMPT
-#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_notrace(); \
} while (0)
#else
#define preempt_enable_notrace() \
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4e925ea10c0c..af0a5a6cee98 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2937,9 +2937,8 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
NOKPROBE_SYMBOL(preempt_schedule);
EXPORT_SYMBOL(preempt_schedule);
-#ifdef CONFIG_CONTEXT_TRACKING
/**
- * preempt_schedule_context - preempt_schedule called by tracing
+ * preempt_schedule_notrace - preempt_schedule called by tracing
*
* The tracing infrastructure uses preempt_enable_notrace to prevent
* recursion and tracing preempt enabling caused by the tracing
@@ -2952,7 +2951,7 @@ EXPORT_SYMBOL(preempt_schedule);
* instead of preempt_schedule() to exit user context if needed before
* calling the scheduler.
*/
-asmlinkage __visible void __sched notrace preempt_schedule_context(void)
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
{
enum ctx_state prev_ctx;
@@ -2980,8 +2979,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_context(void)
__preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET);
} while (need_resched());
}
-EXPORT_SYMBOL_GPL(preempt_schedule_context);
-#endif /* CONFIG_CONTEXT_TRACKING */
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
#endif /* CONFIG_PREEMPT */