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-rw-r--r--include/linux/hash.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/hash.h b/include/linux/hash.h
index bd1754c..d0494c3 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);
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