On Fri, Sep 14, 2018 at 12:41:01AM +0300, Timofey Titovets wrote:
> From: Timofey Titovets <nefelim4ag@xxxxxxxxx>
>
> xxh32() - fast on both 32/64-bit platforms
> xxh64() - fast only on 64-bit platform
>
> Create xxhash() which will pickup fastest version
> on compile time.
>
> As result depends on cpu word size,
> the main proporse of that - in memory hashing.
>
> Changes:
> v2:
> - Create that patch
> v3 -> v8:
> - Nothing, whole patchset version bump
>
> Signed-off-by: Timofey Titovets <nefelim4ag@xxxxxxxxx>
> Reviewed-by: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>
Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
> CC: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> CC: linux-mm@xxxxxxxxx
> CC: kvm@xxxxxxxxxxxxxxx
> CC: leesioh <solee@xxxxxxxxxxxxxx>
> ---
> include/linux/xxhash.h | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/include/linux/xxhash.h b/include/linux/xxhash.h
> index 9e1f42cb57e9..52b073fea17f 100644
> --- a/include/linux/xxhash.h
> +++ b/include/linux/xxhash.h
> @@ -107,6 +107,29 @@ uint32_t xxh32(const void *input, size_t length, uint32_t seed);
> */
> uint64_t xxh64(const void *input, size_t length, uint64_t seed);
>
> +/**
> + * xxhash() - calculate wordsize hash of the input with a given seed
> + * @input: The data to hash.
> + * @length: The length of the data to hash.
> + * @seed: The seed can be used to alter the result predictably.
> + *
> + * If the hash does not need to be comparable between machines with
> + * different word sizes, this function will call whichever of xxh32()
> + * or xxh64() is faster.
> + *
> + * Return: wordsize hash of the data.
> + */
> +
> +static inline unsigned long xxhash(const void *input, size_t length,
> + uint64_t seed)
> +{
> +#if BITS_PER_LONG == 64
> + return xxh64(input, length, seed);
> +#else
> + return xxh32(input, length, seed);
> +#endif
> +}
> +
> /*-****************************
> * Streaming Hash Functions
> *****************************/
> --
> 2.19.0
>
--
Sincerely yours,
Mike.
