preempt.h revision c559cd81139f97cecad1ad91a0b2e25a5936d531 
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
12#ifdef CONFIG_DEBUG_PREEMPT
13  extern void fastcall add_preempt_count(int val);
14  extern void fastcall sub_preempt_count(int val);
15#else
16# define add_preempt_count(val)	do { preempt_count() += (val); } while (0)
17# define sub_preempt_count(val)	do { preempt_count() -= (val); } while (0)
18#endif
19
20#define inc_preempt_count() add_preempt_count(1)
21#define dec_preempt_count() sub_preempt_count(1)
22
23#define preempt_count()	(current_thread_info()->preempt_count)
24
25#ifdef CONFIG_PREEMPT
26
27asmlinkage void preempt_schedule(void);
28
29#define preempt_disable() \
30do { \
31	inc_preempt_count(); \
32	barrier(); \
33} while (0)
34
35#define preempt_enable_no_resched() \
36do { \
37	barrier(); \
38	dec_preempt_count(); \
39} while (0)
40
41#define preempt_check_resched() \
42do { \
43	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
44		preempt_schedule(); \
45} while (0)
46
47#define preempt_enable() \
48do { \
49	preempt_enable_no_resched(); \
50	barrier(); \
51	preempt_check_resched(); \
52} while (0)
53
54#else
55
56#define preempt_disable()		do { } while (0)
57#define preempt_enable_no_resched()	do { } while (0)
58#define preempt_enable()		do { } while (0)
59#define preempt_check_resched()		do { } while (0)
60
61#endif
62
63#endif /* __LINUX_PREEMPT_H */
64