bonding: allow use of tx hashing in balance-alb

The rx load balancing provided by balance-alb is not mutually
exclusive with using hashing for tx selection, and should provide a decent
speed increase because this eliminates spinlocks and cache contention.

Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_alb.c

@@ -1478,8 +1478,24 @@ netdev_tx_t bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 	}
 
 	if (do_tx_balance) {
-		hash_index = _simple_hash(hash_start, hash_size);
-		tx_slave = tlb_choose_channel(bond, hash_index, skb->len);
+		if (bond->params.tlb_dynamic_lb) {
+			hash_index = _simple_hash(hash_start, hash_size);
+			tx_slave = tlb_choose_channel(bond, hash_index, skb->len);
+		} else {
+			/*
+			 * do_tx_balance means we are free to select the tx_slave
+			 * So we do exactly what tlb would do for hash selection
+			 */
+
+			struct bond_up_slave *slaves;
+			unsigned int count;
+
+			slaves = rcu_dereference(bond->slave_arr);
+			count = slaves ? READ_ONCE(slaves->count) : 0;
+			if (likely(count))
+				tx_slave = slaves->arr[bond_xmit_hash(bond, skb) %
+						       count];
+		}
 	}
 
 	return bond_do_alb_xmit(skb, bond, tx_slave);

drivers/net/bonding/bond_main.c

@@ -159,7 +159,7 @@ module_param(min_links, int, 0);
 MODULE_PARM_DESC(min_links, "Minimum number of available links before turning on carrier");
 
 module_param(xmit_hash_policy, charp, 0);
-MODULE_PARM_DESC(xmit_hash_policy, "balance-xor and 802.3ad hashing method; "
+MODULE_PARM_DESC(xmit_hash_policy, "balance-alb, balance-tlb, balance-xor, 802.3ad hashing method; "
 				   "0 for layer 2 (default), 1 for layer 3+4, "
 				   "2 for layer 2+3, 3 for encap layer 2+3, "
 				   "4 for encap layer 3+4");
@@ -1735,7 +1735,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
 		unblock_netpoll_tx();
 	}
 
-	if (bond_mode_uses_xmit_hash(bond))
+	if (bond_mode_can_use_xmit_hash(bond))
 		bond_update_slave_arr(bond, NULL);
 
 	bond->nest_level = dev_get_nest_level(bond_dev);
@@ -1870,7 +1870,7 @@ static int __bond_release_one(struct net_device *bond_dev,
 	if (BOND_MODE(bond) == BOND_MODE_8023AD)
 		bond_3ad_unbind_slave(slave);
 
-	if (bond_mode_uses_xmit_hash(bond))
+	if (bond_mode_can_use_xmit_hash(bond))
 		bond_update_slave_arr(bond, slave);
 
 	netdev_info(bond_dev, "Releasing %s interface %s\n",
@@ -3102,7 +3102,7 @@ static int bond_slave_netdev_event(unsigned long event,
 		 * events. If these (miimon/arpmon) parameters are configured
 		 * then array gets refreshed twice and that should be fine!
 		 */
-		if (bond_mode_uses_xmit_hash(bond))
+		if (bond_mode_can_use_xmit_hash(bond))
 			bond_update_slave_arr(bond, NULL);
 		break;
 	case NETDEV_CHANGEMTU:
@@ -3322,7 +3322,7 @@ static int bond_open(struct net_device *bond_dev)
 		 */
 		if (bond_alb_initialize(bond, (BOND_MODE(bond) == BOND_MODE_ALB)))
 			return -ENOMEM;
-		if (bond->params.tlb_dynamic_lb)
+		if (bond->params.tlb_dynamic_lb || BOND_MODE(bond) == BOND_MODE_ALB)
 			queue_delayed_work(bond->wq, &bond->alb_work, 0);
 	}
 
@@ -3341,7 +3341,7 @@ static int bond_open(struct net_device *bond_dev)
 		bond_3ad_initiate_agg_selection(bond, 1);
 	}
 
-	if (bond_mode_uses_xmit_hash(bond))
+	if (bond_mode_can_use_xmit_hash(bond))
 		bond_update_slave_arr(bond, NULL);
 
 	return 0;
@@ -3894,7 +3894,7 @@ err:
  * to determine the slave interface -
  * (a) BOND_MODE_8023AD
  * (b) BOND_MODE_XOR
- * (c) BOND_MODE_TLB && tlb_dynamic_lb == 0
+ * (c) (BOND_MODE_TLB || BOND_MODE_ALB) && tlb_dynamic_lb == 0
  *
  * The caller is expected to hold RTNL only and NO other lock!
  */
@@ -3947,6 +3947,11 @@ int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave)
 			continue;
 		if (skipslave == slave)
 			continue;
+
+		netdev_dbg(bond->dev,
+			   "Adding slave dev %s to tx hash array[%d]\n",
+			   slave->dev->name, new_arr->count);
+
 		new_arr->arr[new_arr->count++] = slave;
 	}
 
@@ -4324,9 +4329,9 @@ static int bond_check_params(struct bond_params *params)
 	}
 
 	if (xmit_hash_policy) {
-		if ((bond_mode != BOND_MODE_XOR) &&
-		    (bond_mode != BOND_MODE_8023AD) &&
-		    (bond_mode != BOND_MODE_TLB)) {
+		if (bond_mode == BOND_MODE_ROUNDROBIN ||
+		    bond_mode == BOND_MODE_ACTIVEBACKUP ||
+		    bond_mode == BOND_MODE_BROADCAST) {
 			pr_info("xmit_hash_policy param is irrelevant in mode %s\n",
 				bond_mode_name(bond_mode));
 		} else {

drivers/net/bonding/bond_options.c

@@ -395,7 +395,7 @@ static const struct bond_option bond_opts[BOND_OPT_LAST] = {
 		.id = BOND_OPT_TLB_DYNAMIC_LB,
 		.name = "tlb_dynamic_lb",
 		.desc = "Enable dynamic flow shuffling",
-		.unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_TLB)),
+		.unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_TLB) | BIT(BOND_MODE_ALB)),
 		.values = bond_tlb_dynamic_lb_tbl,
 		.flags = BOND_OPTFLAG_IFDOWN,
 		.set = bond_option_tlb_dynamic_lb_set,

include/net/bonding.h

@@ -285,8 +285,15 @@ static inline bool bond_needs_speed_duplex(const struct bonding *bond)
 
 static inline bool bond_is_nondyn_tlb(const struct bonding *bond)
 {
-	return (BOND_MODE(bond) == BOND_MODE_TLB)  &&
-	       (bond->params.tlb_dynamic_lb == 0);
+	return (bond_is_lb(bond) && bond->params.tlb_dynamic_lb == 0);
+}
+
+static inline bool bond_mode_can_use_xmit_hash(const struct bonding *bond)
+{
+	return (BOND_MODE(bond) == BOND_MODE_8023AD ||
+		BOND_MODE(bond) == BOND_MODE_XOR ||
+		BOND_MODE(bond) == BOND_MODE_TLB ||
+		BOND_MODE(bond) == BOND_MODE_ALB);
 }
 
 static inline bool bond_mode_uses_xmit_hash(const struct bonding *bond)