Messages in this thread Patch in this message | | | From | Matthew Wilcox <> | Subject | [PATCH 3/3] bitmap: Use memcmp optimisation in more situations | Date | Wed, 7 Jun 2017 07:29:24 -0700 |
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From: Matthew Wilcox <mawilcox@microsoft.com>
Commit 7dd968163f ("bitmap: bitmap_equal memcmp optimization") was rather more restrictive than necessary; we can use memcmp() to implement bitmap_equal() as long as the number of bits can be proved to be a multiple of 8. And architectures other than s390 may be able to make good use of this optimisation.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> --- include/linux/bitmap.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 0b3e4452b054..26244e0098f0 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -266,10 +266,8 @@ static inline int bitmap_equal(const unsigned long *src1, { if (small_const_nbits(nbits)) return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); -#ifdef CONFIG_S390 - if (__builtin_constant_p(nbits) && (nbits % BITS_PER_LONG) == 0) + if (__builtin_constant_p(nbits & 7) && IS_ALIGNED(nbits, 8)) return !memcmp(src1, src2, nbits / 8); -#endif return __bitmap_equal(src1, src2, nbits); } -- 2.11.0
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