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

[Bayduraev, Alexey V]

On 30.06.2021 20:24, Arnaldo Carvalho de Melo wrote:
> 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?

Yes, __bitmap_intersects is copy-pasted from the kernel sources,
like the others in bitmap.h

Regards,
Alexey

> 
>> 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
>>
>