Re: [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} with bitmap_weight_eq()

Michał Mirosław
2021-11-28T04:39:43Z

On Sat, Nov 27, 2021 at 07:56:57PM -0800, Yury Norov wrote:
> Now as we have bitmap_weight_eq(), switch bitmap_full() and
> bitmap_empty() to using it.
[...]
> -static inline bool bitmap_empty(const unsigned long *src, unsigned nbits)
> -{
> - if (small_const_nbits(nbits))
> - return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
> -
> - return find_first_bit(src, nbits) == nbits;
> -}
[...]
> +static __always_inline bool bitmap_empty(const unsigned long *src, unsigned int nbits)
> +{
> + return bitmap_weight_eq(src, nbits, 0);
> +}
[..]

What's the speed difference? Have you benchmarked this?

Best Regards
Michał Mirosław