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| author | James Morris <james.l.morris@oracle.com> | 2014-11-19 21:32:12 +1100 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2014-11-19 21:32:12 +1100 |
| commit | b10778a00d40b3d9fdaaf5891e802794781ff71c (patch) | |
| tree | 6ba4cbac86eecedc3f30650e7f764ecf00c83898 /include/linux/hash.h | |
| parent | 594081ee7145cc30a3977cb4e218f81213b63dc5 (diff) | |
| parent | bfe01a5ba2490f299e1d2d5508cbbbadd897bbe9 (diff) | |
Merge commit 'v3.17' into next
Diffstat (limited to 'include/linux/hash.h')
| -rw-r--r-- | include/linux/hash.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/hash.h b/include/linux/hash.h index bd1754c7ece..d0494c39939 100644 --- a/include/linux/hash.h +++ b/include/linux/hash.h @@ -37,6 +37,9 @@ static __always_inline u64 hash_64(u64 val, unsigned int bits) { u64 hash = val; +#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 + hash = hash * GOLDEN_RATIO_PRIME_64; +#else /* Sigh, gcc can't optimise this alone like it does for 32 bits. */ u64 n = hash; n <<= 18; @@ -51,6 +54,7 @@ static __always_inline u64 hash_64(u64 val, unsigned int bits) hash += n; n <<= 2; hash += n; +#endif /* High bits are more random, so use them. */ return hash >> (64 - bits); |