Linux kernel mirror (for testing)
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linux
1#ifndef __LINUX_PREEMPT_H
2#define __LINUX_PREEMPT_H
3
4/*
5 * include/linux/preempt.h - macros for accessing and manipulating
6 * preempt_count (used for kernel preemption, interrupt count, etc.)
7 */
8
9#include <linux/thread_info.h>
10#include <linux/linkage.h>
11#include <linux/list.h>
12
13#ifdef CONFIG_DEBUG_PREEMPT
14 extern void add_preempt_count(int val);
15 extern void sub_preempt_count(int val);
16#else
17# define add_preempt_count(val) do { preempt_count() += (val); } while (0)
18# define sub_preempt_count(val) do { preempt_count() -= (val); } while (0)
19#endif
20
21#define inc_preempt_count() add_preempt_count(1)
22#define dec_preempt_count() sub_preempt_count(1)
23
24#define preempt_count() (current_thread_info()->preempt_count)
25
26#ifdef CONFIG_PREEMPT
27
28asmlinkage void preempt_schedule(void);
29
30#define preempt_disable() \
31do { \
32 inc_preempt_count(); \
33 barrier(); \
34} while (0)
35
36#define preempt_enable_no_resched() \
37do { \
38 barrier(); \
39 dec_preempt_count(); \
40} while (0)
41
42#define preempt_check_resched() \
43do { \
44 if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
45 preempt_schedule(); \
46} while (0)
47
48#define preempt_enable() \
49do { \
50 preempt_enable_no_resched(); \
51 barrier(); \
52 preempt_check_resched(); \
53} while (0)
54
55#else
56
57#define preempt_disable() do { } while (0)
58#define preempt_enable_no_resched() do { } while (0)
59#define preempt_enable() do { } while (0)
60#define preempt_check_resched() do { } while (0)
61
62#endif
63
64#ifdef CONFIG_PREEMPT_NOTIFIERS
65
66struct preempt_notifier;
67
68/**
69 * preempt_ops - notifiers called when a task is preempted and rescheduled
70 * @sched_in: we're about to be rescheduled:
71 * notifier: struct preempt_notifier for the task being scheduled
72 * cpu: cpu we're scheduled on
73 * @sched_out: we've just been preempted
74 * notifier: struct preempt_notifier for the task being preempted
75 * next: the task that's kicking us out
76 */
77struct preempt_ops {
78 void (*sched_in)(struct preempt_notifier *notifier, int cpu);
79 void (*sched_out)(struct preempt_notifier *notifier,
80 struct task_struct *next);
81};
82
83/**
84 * preempt_notifier - key for installing preemption notifiers
85 * @link: internal use
86 * @ops: defines the notifier functions to be called
87 *
88 * Usually used in conjunction with container_of().
89 */
90struct preempt_notifier {
91 struct hlist_node link;
92 struct preempt_ops *ops;
93};
94
95void preempt_notifier_register(struct preempt_notifier *notifier);
96void preempt_notifier_unregister(struct preempt_notifier *notifier);
97
98static inline void preempt_notifier_init(struct preempt_notifier *notifier,
99 struct preempt_ops *ops)
100{
101 INIT_HLIST_NODE(¬ifier->link);
102 notifier->ops = ops;
103}
104
105#endif
106
107#endif /* __LINUX_PREEMPT_H */