1. 根目录:
2. tools
3. perf
4. util
5. include
6. linux
7. bitmap.h

#ifndef _PERF_BITOPS_H
#define _PERF_BITOPS_H

#include <string.h>
#include <linux/bitops.h>

int __bitmap_weight(const unsigned long *bitmap, int bits);
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
		 const unsigned long *bitmap2, int bits);

#define BITMAP_LAST_WORD_MASK(nbits)					\
(									\
	((nbits) % BITS_PER_LONG) ?					\
		(1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL		\
)

#define small_const_nbits(nbits) \
	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)

static inline void bitmap_zero(unsigned long *dst, int nbits)
{
	if (small_const_nbits(nbits))
		*dst = 0UL;
	else {
		int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
		memset(dst, 0, len);
	}
}

static inline int bitmap_weight(const unsigned long *src, int nbits)
{
	if (small_const_nbits(nbits))
		return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
	return __bitmap_weight(src, nbits);
}

static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
			     const unsigned long *src2, int nbits)
{
	if (small_const_nbits(nbits))
		*dst = *src1 | *src2;
	else
		__bitmap_or(dst, src1, src2, nbits);
}

#endif /* _PERF_BITOPS_H */