mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-27 14:43:58 +08:00
ba74c1448f
Create a distinction between scheduler related preempt_enable_no_resched() calls and the nearly one hundred other places in the kernel that do not want to reschedule, for one reason or another. This distinction matters for -rt, where the scheduler and the non-scheduler preempt models (and checks) are different. For upstream it's purely documentational. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-gs88fvx2mdv5psnzxnv575ke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
156 lines
4.1 KiB
C
156 lines
4.1 KiB
C
#ifndef __LINUX_PREEMPT_H
|
|
#define __LINUX_PREEMPT_H
|
|
|
|
/*
|
|
* include/linux/preempt.h - macros for accessing and manipulating
|
|
* preempt_count (used for kernel preemption, interrupt count, etc.)
|
|
*/
|
|
|
|
#include <linux/thread_info.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/list.h>
|
|
|
|
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
|
|
extern void add_preempt_count(int val);
|
|
extern void sub_preempt_count(int val);
|
|
#else
|
|
# define add_preempt_count(val) do { preempt_count() += (val); } while (0)
|
|
# define sub_preempt_count(val) do { preempt_count() -= (val); } while (0)
|
|
#endif
|
|
|
|
#define inc_preempt_count() add_preempt_count(1)
|
|
#define dec_preempt_count() sub_preempt_count(1)
|
|
|
|
#define preempt_count() (current_thread_info()->preempt_count)
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
|
|
asmlinkage void preempt_schedule(void);
|
|
|
|
#define preempt_check_resched() \
|
|
do { \
|
|
if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
|
|
preempt_schedule(); \
|
|
} while (0)
|
|
|
|
#else /* !CONFIG_PREEMPT */
|
|
|
|
#define preempt_check_resched() do { } while (0)
|
|
|
|
#endif /* CONFIG_PREEMPT */
|
|
|
|
|
|
#ifdef CONFIG_PREEMPT_COUNT
|
|
|
|
#define preempt_disable() \
|
|
do { \
|
|
inc_preempt_count(); \
|
|
barrier(); \
|
|
} while (0)
|
|
|
|
#define sched_preempt_enable_no_resched() \
|
|
do { \
|
|
barrier(); \
|
|
dec_preempt_count(); \
|
|
} while (0)
|
|
|
|
#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
|
|
|
|
#define preempt_enable() \
|
|
do { \
|
|
preempt_enable_no_resched(); \
|
|
barrier(); \
|
|
preempt_check_resched(); \
|
|
} while (0)
|
|
|
|
/* For debugging and tracer internals only! */
|
|
#define add_preempt_count_notrace(val) \
|
|
do { preempt_count() += (val); } while (0)
|
|
#define sub_preempt_count_notrace(val) \
|
|
do { preempt_count() -= (val); } while (0)
|
|
#define inc_preempt_count_notrace() add_preempt_count_notrace(1)
|
|
#define dec_preempt_count_notrace() sub_preempt_count_notrace(1)
|
|
|
|
#define preempt_disable_notrace() \
|
|
do { \
|
|
inc_preempt_count_notrace(); \
|
|
barrier(); \
|
|
} while (0)
|
|
|
|
#define preempt_enable_no_resched_notrace() \
|
|
do { \
|
|
barrier(); \
|
|
dec_preempt_count_notrace(); \
|
|
} while (0)
|
|
|
|
/* preempt_check_resched is OK to trace */
|
|
#define preempt_enable_notrace() \
|
|
do { \
|
|
preempt_enable_no_resched_notrace(); \
|
|
barrier(); \
|
|
preempt_check_resched(); \
|
|
} while (0)
|
|
|
|
#else /* !CONFIG_PREEMPT_COUNT */
|
|
|
|
#define preempt_disable() do { } while (0)
|
|
#define sched_preempt_enable_no_resched() do { } while (0)
|
|
#define preempt_enable_no_resched() do { } while (0)
|
|
#define preempt_enable() do { } while (0)
|
|
|
|
#define preempt_disable_notrace() do { } while (0)
|
|
#define preempt_enable_no_resched_notrace() do { } while (0)
|
|
#define preempt_enable_notrace() do { } while (0)
|
|
|
|
#endif /* CONFIG_PREEMPT_COUNT */
|
|
|
|
#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
|
|
struct preempt_notifier;
|
|
|
|
/**
|
|
* preempt_ops - notifiers called when a task is preempted and rescheduled
|
|
* @sched_in: we're about to be rescheduled:
|
|
* notifier: struct preempt_notifier for the task being scheduled
|
|
* cpu: cpu we're scheduled on
|
|
* @sched_out: we've just been preempted
|
|
* notifier: struct preempt_notifier for the task being preempted
|
|
* next: the task that's kicking us out
|
|
*
|
|
* Please note that sched_in and out are called under different
|
|
* contexts. sched_out is called with rq lock held and irq disabled
|
|
* while sched_in is called without rq lock and irq enabled. This
|
|
* difference is intentional and depended upon by its users.
|
|
*/
|
|
struct preempt_ops {
|
|
void (*sched_in)(struct preempt_notifier *notifier, int cpu);
|
|
void (*sched_out)(struct preempt_notifier *notifier,
|
|
struct task_struct *next);
|
|
};
|
|
|
|
/**
|
|
* preempt_notifier - key for installing preemption notifiers
|
|
* @link: internal use
|
|
* @ops: defines the notifier functions to be called
|
|
*
|
|
* Usually used in conjunction with container_of().
|
|
*/
|
|
struct preempt_notifier {
|
|
struct hlist_node link;
|
|
struct preempt_ops *ops;
|
|
};
|
|
|
|
void preempt_notifier_register(struct preempt_notifier *notifier);
|
|
void preempt_notifier_unregister(struct preempt_notifier *notifier);
|
|
|
|
static inline void preempt_notifier_init(struct preempt_notifier *notifier,
|
|
struct preempt_ops *ops)
|
|
{
|
|
INIT_HLIST_NODE(¬ifier->link);
|
|
notifier->ops = ops;
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif /* __LINUX_PREEMPT_H */
|