[INET]: Avoid an integer divide in rt_garbage_collect()

Since 'goal' is a signed int, compiler may emit an integer divide
to compute goal/2.

Using a right shift is OK here and less expensive.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 1cc6c23..933b093 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -851,14 +851,14 @@ static int rt_garbage_collect(void)
                        equilibrium = ipv4_dst_ops.gc_thresh;
                goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
                if (goal > 0) {
-                       equilibrium += min_t(unsigned int, goal / 2, rt_hash_mask + 1);
+                       equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
                        goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
                }
        } else {
                /* We are in dangerous area. Try to reduce cache really
                 * aggressively.
                 */
-               goal = max_t(unsigned int, goal / 2, rt_hash_mask + 1);
+               goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
                equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
        }