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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:

  b30f0e3ffe ("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>
This commit is contained in:
Frederic Weisbecker 2015-06-04 17:39:08 +02:00 committed by Ingo Molnar
parent be690035df
commit 4eaca0a887
8 changed files with 13 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/x86/include/asm/preempt.h
View File

@ -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 */

4
arch/x86/kernel/i386_ksyms_32.c
View File

@ -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

4
arch/x86/kernel/x8664_ksyms_64.c
View File

@ -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

4
arch/x86/lib/thunk_32.S
View File

@ -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

4
arch/x86/lib/thunk_64.S
View File

@ -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) \

7
include/asm-generic/preempt.h
View File

@ -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 */

6
include/linux/preempt.h
View File

@ -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() \

8
kernel/sched/core.c
View File

@ -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 */