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Message-Id: <1433432349-1021-3-git-send-email-fweisbec@gmail.com>
Date: Thu, 4 Jun 2015 17:39:08 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Fengguang Wu <fengguang.wu@...el.com>,
Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH 2/3] 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 b30f0e3ffedfa52b1d67a302ae5860c49998e5e2
("sched/preempt: Optimize preemption operations on __schedule() callers")
introduced function based preemp_coun_*() 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@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Fengguang Wu <fengguang.wu@...el.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
arch/x86/include/asm/preempt.h | 8 +++-----
arch/x86/kernel/i386_ksyms_32.c | 4 +---
arch/x86/kernel/x8664_ksyms_64.c | 4 +---
arch/x86/lib/thunk_32.S | 4 +---
arch/x86/lib/thunk_64.S | 4 +---
include/asm-generic/preempt.h | 7 ++-----
include/linux/preempt.h | 6 +-----
kernel/sched/core.c | 8 +++-----
8 files changed, 13 insertions(+), 32 deletions(-)
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 8f327184..dca7171 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 05fd74f..64341aa 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 37d8fa4..a0695be 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 5eb7150..e407941 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 f89ba4e9..2198902 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 eb6f9e6..d0a7a47 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 a1a00e1..7686dd6 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 4c3d41f..053947a 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 */
--
2.1.4
--
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