include/asm-generic/bitops/sched.h

   1 #ifndef _ASM_GENERIC_BITOPS_SCHED_H_
   2 #define _ASM_GENERIC_BITOPS_SCHED_H_
   3
   4 #include <linux/compiler.h>     /* unlikely() */
   5 #include <asm/types.h>
   6
   7 /*
   8  * Every architecture must define this function. It's the fastest
   9  * way of searching a 140-bit bitmap where the first 100 bits are
  10  * unlikely to be set. It's guaranteed that at least one of the 140
  11  * bits is cleared.
  12  */
  13 static inline int sched_find_first_bit(const unsigned long *b)
  14 {
  15 #if BITS_PER_LONG == 64
  16         if (unlikely(b[0]))
  17                 return __ffs(b[0]);
  18         if (likely(b[1]))
  19                 return __ffs(b[1]) + 64;
  20         return __ffs(b[2]) + 128;
  21 #elif BITS_PER_LONG == 32
  22         if (unlikely(b[0]))
  23                 return __ffs(b[0]);
  24         if (unlikely(b[1]))
  25                 return __ffs(b[1]) + 32;
  26         if (unlikely(b[2]))
  27                 return __ffs(b[2]) + 64;
  28         if (b[3])
  29                 return __ffs(b[3]) + 96;
  30         return __ffs(b[4]) + 128;
  31 #else
  32 #error BITS_PER_LONG not defined
  33 #endif
  34 }
  35
  36 #endif /* _ASM_GENERIC_BITOPS_SCHED_H_ */