[PATCH] bonding-tlb: better balance when choosing slaves

["Weiping Pan(潘卫平)" <panweiping3@gmail.com>]

tlb_get_least_loaded_slave() always chooses slave from
bonding->first_slave, that gives the beginnig slaves more chances to be used.

Let tlb_get_least_loaded_slave() chooses slave from a random positon in the
slave list, make all slaves transmit packets more balanced.

Signed-off-by: Weiping Pan(潘卫平) <panweiping3@gmail.com>
---
 drivers/net/bonding/bond_alb.c |   17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 9bc5de3..9fa64b0 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -36,6 +36,7 @@
 #include <linux/if_bonding.h>
 #include <linux/if_vlan.h>
 #include <linux/in.h>
+#include <linux/random.h>
 #include <net/ipx.h>
 #include <net/arp.h>
 #include <net/ipv6.h>
@@ -206,15 +207,27 @@ static long long compute_gap(struct slave *slave)
 /* Caller must hold bond lock for read */
 static struct slave *tlb_get_least_loaded_slave(struct bonding *bond)
 {
-	struct slave *slave, *least_loaded;
+	struct slave *slave, *least_loaded, *start_slave;
 	long long max_gap;
 	int i;
+	u8 n;
 
 	least_loaded = NULL;
+	start_slave = bond->first_slave;
 	max_gap = LLONG_MIN;
+        
+	get_random_bytes(&n, 1);
+
+	if (bond->slave_cnt == 0)
+		return NULL;
+	n = n % bond->slave_cnt;
+
+	for (i=0; i<n; ++i) {
+		start_slave = start_slave->next;
+	}
 
 	/* Find the slave with the largest gap */
-	bond_for_each_slave(bond, slave, i) {
+	bond_for_each_slave_from(bond, slave, i, start_slave) {
 		if (SLAVE_IS_OK(slave)) {
 			long long gap = compute_gap(slave);
 
-- 
1.7.4