+/*
+ * Algorithm to find the log2 of a 32-bit unsigned integer.
+ * source: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
+ * Originally from Public Domain.
+ */
+static const char LogTable256[256] =
+{
+#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
+ -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+ LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
+ LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
+};
+
+uint32_t log2_u32(uint32_t v)
+{
+ uint32_t t, tt;
+
+ if ((tt = (v >> 16)))
+ return (t = (tt >> 8))
+ ? 24 + LogTable256[t]
+ : 16 + LogTable256[tt];
+ else
+ return (t = (v >> 8))
+ ? 8 + LogTable256[t]
+ : LogTable256[v];
+}
+
+static
+void ht_resize_lazy(struct rcu_ht *ht, struct rcu_table *t, int growth);
+
+static
+void check_resize(struct rcu_ht *ht, struct rcu_table *t,
+ uint32_t chain_len)
+{
+ if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD)
+ ht_resize_lazy(ht, t,
+ log2_u32(chain_len - CHAIN_LEN_TARGET - 1));
+}
+