tmp_suning_uos_patched/include/asm-generic/preempt.h
Frederic Weisbecker 4eaca0a887 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>
2015-06-07 15:57:42 +02:00

87 lines
1.8 KiB
C

#ifndef __ASM_PREEMPT_H
#define __ASM_PREEMPT_H
#include <linux/thread_info.h>
#define PREEMPT_ENABLED (0)
static __always_inline int preempt_count(void)
{
return current_thread_info()->preempt_count;
}
static __always_inline int *preempt_count_ptr(void)
{
return &current_thread_info()->preempt_count;
}
static __always_inline void preempt_count_set(int pc)
{
*preempt_count_ptr() = pc;
}
/*
* must be macros to avoid header recursion hell
*/
#define init_task_preempt_count(p) do { \
task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
} while (0)
#define init_idle_preempt_count(p, cpu) do { \
task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
} while (0)
static __always_inline void set_preempt_need_resched(void)
{
}
static __always_inline void clear_preempt_need_resched(void)
{
}
static __always_inline bool test_preempt_need_resched(void)
{
return false;
}
/*
* The various preempt_count add/sub methods
*/
static __always_inline void __preempt_count_add(int val)
{
*preempt_count_ptr() += val;
}
static __always_inline void __preempt_count_sub(int val)
{
*preempt_count_ptr() -= val;
}
static __always_inline bool __preempt_count_dec_and_test(void)
{
/*
* Because of load-store architectures cannot do per-cpu atomic
* operations; we cannot use PREEMPT_NEED_RESCHED because it might get
* lost.
*/
return !--*preempt_count_ptr() && tif_need_resched();
}
/*
* Returns true when we need to resched and can (barring IRQ state).
*/
static __always_inline bool should_resched(void)
{
return unlikely(!preempt_count() && tif_need_resched());
}
#ifdef CONFIG_PREEMPT
extern asmlinkage void preempt_schedule(void);
#define __preempt_schedule() preempt_schedule()
extern asmlinkage void preempt_schedule_notrace(void);
#define __preempt_schedule_notrace() preempt_schedule_notrace()
#endif /* CONFIG_PREEMPT */
#endif /* __ASM_PREEMPT_H */