Messages in this thread | | | From | Andy Shevchenko <> | Date | Thu, 8 Jun 2017 04:48:04 +0300 | Subject | Re: [PATCH 3/3] bitmap: Use memcmp optimisation in more situations |
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On Wed, Jun 7, 2017 at 5:29 PM, Matthew Wilcox <willy@infradead.org> wrote:
> 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.
> - 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);
I'm not sure this is a fully correct change. What exactly ' & 7' part does? For me looks like you may just drop it.
-- With Best Regards, Andy Shevchenko
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