Re: [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} with bitmap_weight_eq()
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Date: 2021-11-28 04:39:45
Also in:
kvm, linux-alpha, linux-crypto, linux-mips, linux-mm, linux-perf-users, linux-riscv, linux-s390, lkml
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;
-}[...]
quoted hunk ↗ jump to hunk
+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