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1da177e4 LT |
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 | ||
f037360f | 9 | #include <linux/thread_info.h> |
1da177e4 | 10 | #include <linux/linkage.h> |
e107be36 | 11 | #include <linux/list.h> |
1da177e4 | 12 | |
6cd8a4bb | 13 | #if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER) |
ec701584 HH |
14 | extern void add_preempt_count(int val); |
15 | extern void sub_preempt_count(int val); | |
1da177e4 LT |
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 | ||
28 | asmlinkage void preempt_schedule(void); | |
29 | ||
30 | #define preempt_disable() \ | |
31 | do { \ | |
32 | inc_preempt_count(); \ | |
33 | barrier(); \ | |
34 | } while (0) | |
35 | ||
36 | #define preempt_enable_no_resched() \ | |
37 | do { \ | |
38 | barrier(); \ | |
39 | dec_preempt_count(); \ | |
40 | } while (0) | |
41 | ||
42 | #define preempt_check_resched() \ | |
43 | do { \ | |
44 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \ | |
45 | preempt_schedule(); \ | |
46 | } while (0) | |
47 | ||
48 | #define preempt_enable() \ | |
49 | do { \ | |
50 | preempt_enable_no_resched(); \ | |
d6f02913 | 51 | barrier(); \ |
1da177e4 LT |
52 | preempt_check_resched(); \ |
53 | } while (0) | |
54 | ||
50282528 SR |
55 | /* For debugging and tracer internals only! */ |
56 | #define add_preempt_count_notrace(val) \ | |
57 | do { preempt_count() += (val); } while (0) | |
58 | #define sub_preempt_count_notrace(val) \ | |
59 | do { preempt_count() -= (val); } while (0) | |
60 | #define inc_preempt_count_notrace() add_preempt_count_notrace(1) | |
61 | #define dec_preempt_count_notrace() sub_preempt_count_notrace(1) | |
62 | ||
63 | #define preempt_disable_notrace() \ | |
64 | do { \ | |
65 | inc_preempt_count_notrace(); \ | |
66 | barrier(); \ | |
67 | } while (0) | |
68 | ||
69 | #define preempt_enable_no_resched_notrace() \ | |
70 | do { \ | |
71 | barrier(); \ | |
72 | dec_preempt_count_notrace(); \ | |
73 | } while (0) | |
74 | ||
75 | /* preempt_check_resched is OK to trace */ | |
76 | #define preempt_enable_notrace() \ | |
77 | do { \ | |
78 | preempt_enable_no_resched_notrace(); \ | |
79 | barrier(); \ | |
80 | preempt_check_resched(); \ | |
81 | } while (0) | |
82 | ||
1da177e4 LT |
83 | #else |
84 | ||
85 | #define preempt_disable() do { } while (0) | |
86 | #define preempt_enable_no_resched() do { } while (0) | |
87 | #define preempt_enable() do { } while (0) | |
88 | #define preempt_check_resched() do { } while (0) | |
89 | ||
50282528 SR |
90 | #define preempt_disable_notrace() do { } while (0) |
91 | #define preempt_enable_no_resched_notrace() do { } while (0) | |
92 | #define preempt_enable_notrace() do { } while (0) | |
93 | ||
1da177e4 LT |
94 | #endif |
95 | ||
e107be36 AK |
96 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
97 | ||
98 | struct preempt_notifier; | |
99 | ||
100 | /** | |
101 | * preempt_ops - notifiers called when a task is preempted and rescheduled | |
102 | * @sched_in: we're about to be rescheduled: | |
103 | * notifier: struct preempt_notifier for the task being scheduled | |
104 | * cpu: cpu we're scheduled on | |
105 | * @sched_out: we've just been preempted | |
106 | * notifier: struct preempt_notifier for the task being preempted | |
107 | * next: the task that's kicking us out | |
108 | */ | |
109 | struct preempt_ops { | |
110 | void (*sched_in)(struct preempt_notifier *notifier, int cpu); | |
111 | void (*sched_out)(struct preempt_notifier *notifier, | |
112 | struct task_struct *next); | |
113 | }; | |
114 | ||
115 | /** | |
116 | * preempt_notifier - key for installing preemption notifiers | |
117 | * @link: internal use | |
118 | * @ops: defines the notifier functions to be called | |
119 | * | |
120 | * Usually used in conjunction with container_of(). | |
121 | */ | |
122 | struct preempt_notifier { | |
123 | struct hlist_node link; | |
124 | struct preempt_ops *ops; | |
125 | }; | |
126 | ||
127 | void preempt_notifier_register(struct preempt_notifier *notifier); | |
128 | void preempt_notifier_unregister(struct preempt_notifier *notifier); | |
129 | ||
130 | static inline void preempt_notifier_init(struct preempt_notifier *notifier, | |
131 | struct preempt_ops *ops) | |
132 | { | |
133 | INIT_HLIST_NODE(¬ifier->link); | |
134 | notifier->ops = ops; | |
135 | } | |
136 | ||
137 | #endif | |
138 | ||
1da177e4 | 139 | #endif /* __LINUX_PREEMPT_H */ |