Re: [PATCH v8 09/22] tools lib: Introduce bitmap_intersects() operation

[Arnaldo Carvalho de Melo]

Em Wed, Jun 30, 2021 at 06:54:48PM +0300, Alexey Bayduraev escreveu:
> Introduce bitmap_intersects() routine that tests whether

Is this _adopting_ bitmap_intersects() from the kernel sources?

> bitmaps bitmap1 and bitmap2 intersects. This routine will
> be used during thread masks initialization.
> 
> Acked-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Acked-by: Namhyung Kim <namhyung@xxxxxxxxx>
> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@xxxxxxxxxxxxxxx>
> ---
>  tools/include/linux/bitmap.h | 11 +++++++++++
>  tools/lib/bitmap.c           | 14 ++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
> index 330dbf7509cc..9d959bc24859 100644
> --- a/tools/include/linux/bitmap.h
> +++ b/tools/include/linux/bitmap.h
> @@ -18,6 +18,8 @@ int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
>  int __bitmap_equal(const unsigned long *bitmap1,
>  		   const unsigned long *bitmap2, unsigned int bits);
>  void bitmap_clear(unsigned long *map, unsigned int start, int len);
> +int __bitmap_intersects(const unsigned long *bitmap1,
> +			const unsigned long *bitmap2, unsigned int bits);
>  
>  #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
>  #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
> @@ -170,4 +172,13 @@ static inline int bitmap_equal(const unsigned long *src1,
>  	return __bitmap_equal(src1, src2, nbits);
>  }
>  
> +static inline int bitmap_intersects(const unsigned long *src1,
> +			const unsigned long *src2, unsigned int nbits)
> +{
> +	if (small_const_nbits(nbits))
> +		return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
> +	else
> +		return __bitmap_intersects(src1, src2, nbits);
> +}
> +
>  #endif /* _PERF_BITOPS_H */
> diff --git a/tools/lib/bitmap.c b/tools/lib/bitmap.c
> index f4e914712b6f..db466ef7be9d 100644
> --- a/tools/lib/bitmap.c
> +++ b/tools/lib/bitmap.c
> @@ -86,3 +86,17 @@ int __bitmap_equal(const unsigned long *bitmap1,
>  
>  	return 1;
>  }
> +
> +int __bitmap_intersects(const unsigned long *bitmap1,
> +			const unsigned long *bitmap2, unsigned int bits)
> +{
> +	unsigned int k, lim = bits/BITS_PER_LONG;
> +	for (k = 0; k < lim; ++k)
> +		if (bitmap1[k] & bitmap2[k])
> +			return 1;
> +
> +	if (bits % BITS_PER_LONG)
> +		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
> +			return 1;
> +	return 0;
> +}
> -- 
> 2.19.0
> 

-- 

- Arnaldo