include/linux/preempt.h

   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/config.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
  27 asmlinkage void preempt_schedule(void);
  28
  29 #define preempt_disable() \
  30 do { \
  31         inc_preempt_count(); \
  32         barrier(); \
  33 } while (0)
  34
  35 #define preempt_enable_no_resched() \
  36 do { \
  37         barrier(); \
  38         dec_preempt_count(); \
  39 } while (0)
  40
  41 #define preempt_check_resched() \
  42 do { \
  43         if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
  44                 preempt_schedule(); \
  45 } while (0)
  46
  47 #define preempt_enable() \
  48 do { \
  49         preempt_enable_no_resched(); \
  50         preempt_check_resched(); \
  51 } while (0)
  52
  53 #else
  54
  55 #define preempt_disable()               do { } while (0)
  56 #define preempt_enable_no_resched()     do { } while (0)
  57 #define preempt_enable()                do { } while (0)
  58 #define preempt_check_resched()         do { } while (0)
  59
  60 #endif
  61
  62 #endif /* __LINUX_PREEMPT_H */