diff mbox

[net-next-2.6,V3] net: convert bonding to use rx_handler

Message ID 20110219080523.GB2782@psychotron.redhat.com
State Superseded, archived
Delegated to: David Miller
Headers show

Commit Message

Jiri Pirko Feb. 19, 2011, 8:05 a.m. UTC 
This patch converts bonding to use rx_handler. Results in cleaner
__netif_receive_skb() with much less exceptions needed. Also
bond-specific work is moved into bond code.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>

v1->v2:
        using skb_iif instead of new input_dev to remember original
	device
v2->v3:
	set orig_dev = skb->dev if skb_iif is set

---
 drivers/net/bonding/bond_main.c |   75 ++++++++++++++++++++++++-
 net/core/dev.c                  |  120 +++++++++-----------------------------
 2 files changed, 103 insertions(+), 92 deletions(-)

Comments

Eric Dumazet Feb. 19, 2011, 8:37 a.m. UTC | #1 
Le samedi 19 février 2011 à 09:05 +0100, Jiri Pirko a écrit :
> This patch converts bonding to use rx_handler. Results in cleaner
> __netif_receive_skb() with much less exceptions needed. Also
> bond-specific work is moved into bond code.
> 
> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
> 
> v1->v2:
>         using skb_iif instead of new input_dev to remember original
> 	device
> v2->v3:
> 	set orig_dev = skb->dev if skb_iif is set
> 

Seems much better ;)

Do you have some performance numbers ?



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jiri Pirko Feb. 19, 2011, 8:58 a.m. UTC | #2 
Sat, Feb 19, 2011 at 09:37:55AM CET, eric.dumazet@gmail.com wrote:
>Le samedi 19 février 2011 à 09:05 +0100, Jiri Pirko a écrit :
>> This patch converts bonding to use rx_handler. Results in cleaner
>> __netif_receive_skb() with much less exceptions needed. Also
>> bond-specific work is moved into bond code.
>> 
>> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
>> 
>> v1->v2:
>>         using skb_iif instead of new input_dev to remember original
>> 	device
>> v2->v3:
>> 	set orig_dev = skb->dev if skb_iif is set
>> 
>
>Seems much better ;)
>
>Do you have some performance numbers ?

I don't. I can surely obtain some. What's the best way to measure this?

>
>
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Eric Dumazet Feb. 19, 2011, 9:22 a.m. UTC | #3 
Le samedi 19 février 2011 à 09:58 +0100, Jiri Pirko a écrit :
> Sat, Feb 19, 2011 at 09:37:55AM CET, eric.dumazet@gmail.com wrote:
> >Le samedi 19 février 2011 à 09:05 +0100, Jiri Pirko a écrit :
> >> This patch converts bonding to use rx_handler. Results in cleaner
> >> __netif_receive_skb() with much less exceptions needed. Also
> >> bond-specific work is moved into bond code.
> >> 
> >> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
> >> 
> >> v1->v2:
> >>         using skb_iif instead of new input_dev to remember original
> >> 	device
> >> v2->v3:
> >> 	set orig_dev = skb->dev if skb_iif is set
> >> 
> >
> >Seems much better ;)
> >
> >Do you have some performance numbers ?
> 
> I don't. I can surely obtain some. What's the best way to measure this?
> 

Hmm, since its receive path :

Two machines, one sending (pktgen) a flood, one receiving it and
check/count how many frames hit destination, before/after patch.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Nicolas de Pesloüan Feb. 19, 2011, 10:56 a.m. UTC | #4 
Le 19/02/2011 09:05, Jiri Pirko a écrit :
> This patch converts bonding to use rx_handler. Results in cleaner
> __netif_receive_skb() with much less exceptions needed. Also
> bond-specific work is moved into bond code.
>
> Signed-off-by: Jiri Pirko<jpirko@redhat.com>
>
> v1->v2:
>          using skb_iif instead of new input_dev to remember original
> 	device
> v2->v3:
> 	set orig_dev = skb->dev if skb_iif is set
>

Why do we need to let the rx_handlers call netif_rx() or __netif_receive_skb()?

Bonding used to be handled with very few overhead, simply replacing skb->dev with skb->dev->master. 
Time has passed and we eventually added many special processing for bonding into 
__netif_receive_skb(), but the overhead remained very light.

Calling netif_rx() (or __netif_receive_skb()) to allow nesting would probably lead to some overhead.

Can't we, instead, loop inside __netif_receive_skb(), and deliver whatever need to be delivered, to 
whoever need, inside the loop ?

rx_handler = rcu_dereference(skb->dev->rx_handler);
while (rx_handler) {
	/* ...  */
	orig_dev = skb->dev;
	skb = rx_handler(skb);
	/* ... */
	rx_handler = (skb->dev != orig_dev) ? rcu_dereference(skb->dev->rx_handler) : NULL;
}

This would reduce the overhead, while still allowing nesting: vlan on top on bonding, bridge on top 
on bonding, ...

That way, we can probably keep the list of crossed devices inside a local array, and call 
deliver_skb() with the current "orig_dev" when appropriate. No need to overload sk_buff nor to use a 
global variable.

Of course, this might be a very simplistic view.

Any comments?

	Nicolas.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jiri Pirko Feb. 19, 2011, 11:08 a.m. UTC | #5 
Sat, Feb 19, 2011 at 11:56:23AM CET, nicolas.2p.debian@gmail.com wrote:
>Le 19/02/2011 09:05, Jiri Pirko a écrit :
>>This patch converts bonding to use rx_handler. Results in cleaner
>>__netif_receive_skb() with much less exceptions needed. Also
>>bond-specific work is moved into bond code.
>>
>>Signed-off-by: Jiri Pirko<jpirko@redhat.com>
>>
>>v1->v2:
>>         using skb_iif instead of new input_dev to remember original
>>	device
>>v2->v3:
>>	set orig_dev = skb->dev if skb_iif is set
>>
>
>Why do we need to let the rx_handlers call netif_rx() or __netif_receive_skb()?
>
>Bonding used to be handled with very few overhead, simply replacing
>skb->dev with skb->dev->master. Time has passed and we eventually
>added many special processing for bonding into __netif_receive_skb(),
>but the overhead remained very light.
>
>Calling netif_rx() (or __netif_receive_skb()) to allow nesting would probably lead to some overhead.
>
>Can't we, instead, loop inside __netif_receive_skb(), and deliver
>whatever need to be delivered, to whoever need, inside the loop ?
>
>rx_handler = rcu_dereference(skb->dev->rx_handler);
>while (rx_handler) {
>	/* ...  */
>	orig_dev = skb->dev;
>	skb = rx_handler(skb);
>	/* ... */
>	rx_handler = (skb->dev != orig_dev) ? rcu_dereference(skb->dev->rx_handler) : NULL;
>}
>
>This would reduce the overhead, while still allowing nesting: vlan on
>top on bonding, bridge on top on bonding, ...

I see your point. Makes sense to me. But the loop would have to include
at least processing of ptype_all too. I'm going to cook a follow-up
patch.

>
>That way, we can probably keep the list of crossed devices inside a
>local array, and call deliver_skb() with the current "orig_dev" when
>appropriate. No need to overload sk_buff nor to use a global
>variable.
>
>Of course, this might be a very simplistic view.
>
>Any comments?
>
>	Nicolas.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 77e3c6a..a856a11 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1423,6 +1423,68 @@  static void bond_setup_by_slave(struct net_device *bond_dev,
 	bond->setup_by_slave = 1;
 }
 
+/* On bonding slaves other than the currently active slave, suppress
+ * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and
+ * ARP on active-backup slaves with arp_validate enabled.
+ */
+static bool bond_should_deliver_exact_match(struct sk_buff *skb,
+					    struct net_device *slave_dev,
+					    struct net_device *bond_dev)
+{
+	if (slave_dev->priv_flags & IFF_SLAVE_INACTIVE) {
+		if (slave_dev->priv_flags & IFF_SLAVE_NEEDARP &&
+		    skb->protocol == __cpu_to_be16(ETH_P_ARP))
+			return false;
+
+		if (bond_dev->priv_flags & IFF_MASTER_ALB &&
+		    skb->pkt_type != PACKET_BROADCAST &&
+		    skb->pkt_type != PACKET_MULTICAST)
+				return false;
+
+		if (bond_dev->priv_flags & IFF_MASTER_8023AD &&
+		    skb->protocol == __cpu_to_be16(ETH_P_SLOW))
+			return false;
+
+		return true;
+	}
+	return false;
+}
+
+static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
+{
+	struct net_device *slave_dev;
+	struct net_device *bond_dev;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return NULL;
+	slave_dev = skb->dev;
+	bond_dev = ACCESS_ONCE(slave_dev->master);
+	if (unlikely(!bond_dev))
+		return skb;
+
+	if (bond_dev->priv_flags & IFF_MASTER_ARPMON)
+		slave_dev->last_rx = jiffies;
+
+	if (bond_should_deliver_exact_match(skb, slave_dev, bond_dev)) {
+		skb->deliver_no_wcard = 1;
+		return skb;
+	}
+
+	skb->dev = bond_dev;
+
+	if (bond_dev->priv_flags & IFF_MASTER_ALB &&
+	    bond_dev->priv_flags & IFF_BRIDGE_PORT &&
+	    skb->pkt_type == PACKET_HOST) {
+		u16 *dest = (u16 *) eth_hdr(skb)->h_dest;
+
+		memcpy(dest, bond_dev->dev_addr, ETH_ALEN);
+	}
+
+	netif_rx(skb);
+	return NULL;
+}
+
 /* enslave device <slave> to bond device <master> */
 int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 {
@@ -1599,11 +1661,17 @@  int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 		pr_debug("Error %d calling netdev_set_bond_master\n", res);
 		goto err_restore_mac;
 	}
+	res = netdev_rx_handler_register(slave_dev, bond_handle_frame, NULL);
+	if (res) {
+		pr_debug("Error %d calling netdev_rx_handler_register\n", res);
+		goto err_unset_master;
+	}
+
 	/* open the slave since the application closed it */
 	res = dev_open(slave_dev);
 	if (res) {
 		pr_debug("Opening slave %s failed\n", slave_dev->name);
-		goto err_unset_master;
+		goto err_unreg_rxhandler;
 	}
 
 	new_slave->dev = slave_dev;
@@ -1811,6 +1879,9 @@  int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 err_close:
 	dev_close(slave_dev);
 
+err_unreg_rxhandler:
+	netdev_rx_handler_unregister(slave_dev);
+
 err_unset_master:
 	netdev_set_bond_master(slave_dev, NULL);
 
@@ -1992,6 +2063,7 @@  int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 		netif_addr_unlock_bh(bond_dev);
 	}
 
+	netdev_rx_handler_unregister(slave_dev);
 	netdev_set_bond_master(slave_dev, NULL);
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -2114,6 +2186,7 @@  static int bond_release_all(struct net_device *bond_dev)
 			netif_addr_unlock_bh(bond_dev);
 		}
 
+		netdev_rx_handler_unregister(slave_dev);
 		netdev_set_bond_master(slave_dev, NULL);
 
 		/* close slave before restoring its mac address */
diff --git a/net/core/dev.c b/net/core/dev.c
index 4f69439..4ebf7fe 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3092,54 +3092,23 @@  void netdev_rx_handler_unregister(struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister);
 
-static inline void skb_bond_set_mac_by_master(struct sk_buff *skb,
-					      struct net_device *master)
+static void vlan_on_bond_hook(struct sk_buff *skb)
 {
-	if (skb->pkt_type == PACKET_HOST) {
-		u16 *dest = (u16 *) eth_hdr(skb)->h_dest;
-
-		memcpy(dest, master->dev_addr, ETH_ALEN);
-	}
-}
-
-/* On bonding slaves other than the currently active slave, suppress
- * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and
- * ARP on active-backup slaves with arp_validate enabled.
- */
-static int __skb_bond_should_drop(struct sk_buff *skb,
-				  struct net_device *master)
-{
-	struct net_device *dev = skb->dev;
-
-	if (master->priv_flags & IFF_MASTER_ARPMON)
-		dev->last_rx = jiffies;
-
-	if ((master->priv_flags & IFF_MASTER_ALB) &&
-	    (master->priv_flags & IFF_BRIDGE_PORT)) {
-		/* Do address unmangle. The local destination address
-		 * will be always the one master has. Provides the right
-		 * functionality in a bridge.
-		 */
-		skb_bond_set_mac_by_master(skb, master);
-	}
-
-	if (dev->priv_flags & IFF_SLAVE_INACTIVE) {
-		if ((dev->priv_flags & IFF_SLAVE_NEEDARP) &&
-		    skb->protocol == __cpu_to_be16(ETH_P_ARP))
-			return 0;
-
-		if (master->priv_flags & IFF_MASTER_ALB) {
-			if (skb->pkt_type != PACKET_BROADCAST &&
-			    skb->pkt_type != PACKET_MULTICAST)
-				return 0;
-		}
-		if (master->priv_flags & IFF_MASTER_8023AD &&
-		    skb->protocol == __cpu_to_be16(ETH_P_SLOW))
-			return 0;
+	/*
+	 * Make sure ARP frames received on VLAN interfaces stacked on
+	 * bonding interfaces still make their way to any base bonding
+	 * device that may have registered for a specific ptype.
+	 */
+	if (skb->dev->priv_flags & IFF_802_1Q_VLAN &&
+	    vlan_dev_real_dev(skb->dev)->priv_flags & IFF_BONDING &&
+	    skb->protocol == htons(ETH_P_ARP)) {
+		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
-		return 1;
+		if (!skb2)
+			return;
+		skb2->dev = vlan_dev_real_dev(skb->dev);
+		netif_rx(skb2);
 	}
-	return 0;
 }
 
 static int __netif_receive_skb(struct sk_buff *skb)
@@ -3147,8 +3116,7 @@  static int __netif_receive_skb(struct sk_buff *skb)
 	struct packet_type *ptype, *pt_prev;
 	rx_handler_func_t *rx_handler;
 	struct net_device *orig_dev;
-	struct net_device *null_or_orig;
-	struct net_device *orig_or_bond;
+	struct net_device *null_or_dev;
 	int ret = NET_RX_DROP;
 	__be16 type;
 
@@ -3161,33 +3129,6 @@  static int __netif_receive_skb(struct sk_buff *skb)
 	if (netpoll_receive_skb(skb))
 		return NET_RX_DROP;
 
-	if (!skb->skb_iif)
-		skb->skb_iif = skb->dev->ifindex;
-
-	/*
-	 * bonding note: skbs received on inactive slaves should only
-	 * be delivered to pkt handlers that are exact matches.  Also
-	 * the deliver_no_wcard flag will be set.  If packet handlers
-	 * are sensitive to duplicate packets these skbs will need to
-	 * be dropped at the handler.
-	 */
-	null_or_orig = NULL;
-	orig_dev = skb->dev;
-	if (skb->deliver_no_wcard)
-		null_or_orig = orig_dev;
-	else if (netif_is_bond_slave(orig_dev)) {
-		struct net_device *bond_master = ACCESS_ONCE(orig_dev->master);
-
-		if (likely(bond_master)) {
-			if (__skb_bond_should_drop(skb, bond_master)) {
-				skb->deliver_no_wcard = 1;
-				/* deliver only exact match */
-				null_or_orig = orig_dev;
-			} else
-				skb->dev = bond_master;
-		}
-	}
-
 	__this_cpu_inc(softnet_data.processed);
 	skb_reset_network_header(skb);
 	skb_reset_transport_header(skb);
@@ -3197,6 +3138,13 @@  static int __netif_receive_skb(struct sk_buff *skb)
 
 	rcu_read_lock();
 
+	if (!skb->skb_iif) {
+		skb->skb_iif = skb->dev->ifindex;
+		orig_dev = skb->dev;
+	} else {
+		orig_dev = dev_get_by_index_rcu(dev_net(skb->dev), skb->skb_iif);
+	}
+
 #ifdef CONFIG_NET_CLS_ACT
 	if (skb->tc_verd & TC_NCLS) {
 		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
@@ -3205,8 +3153,7 @@  static int __netif_receive_skb(struct sk_buff *skb)
 #endif
 
 	list_for_each_entry_rcu(ptype, &ptype_all, list) {
-		if (ptype->dev == null_or_orig || ptype->dev == skb->dev ||
-		    ptype->dev == orig_dev) {
+		if (!ptype->dev || ptype->dev == skb->dev) {
 			if (pt_prev)
 				ret = deliver_skb(skb, pt_prev, orig_dev);
 			pt_prev = ptype;
@@ -3220,7 +3167,6 @@  static int __netif_receive_skb(struct sk_buff *skb)
 ncls:
 #endif
 
-	/* Handle special case of bridge or macvlan */
 	rx_handler = rcu_dereference(skb->dev->rx_handler);
 	if (rx_handler) {
 		if (pt_prev) {
@@ -3244,24 +3190,16 @@  ncls:
 			goto out;
 	}
 
-	/*
-	 * Make sure frames received on VLAN interfaces stacked on
-	 * bonding interfaces still make their way to any base bonding
-	 * device that may have registered for a specific ptype.  The
-	 * handler may have to adjust skb->dev and orig_dev.
-	 */
-	orig_or_bond = orig_dev;
-	if ((skb->dev->priv_flags & IFF_802_1Q_VLAN) &&
-	    (vlan_dev_real_dev(skb->dev)->priv_flags & IFF_BONDING)) {
-		orig_or_bond = vlan_dev_real_dev(skb->dev);
-	}
+	vlan_on_bond_hook(skb);
+
+	/* deliver only exact match when indicated */
+	null_or_dev = skb->deliver_no_wcard ? skb->dev : NULL;
 
 	type = skb->protocol;
 	list_for_each_entry_rcu(ptype,
 			&ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
-		if (ptype->type == type && (ptype->dev == null_or_orig ||
-		     ptype->dev == skb->dev || ptype->dev == orig_dev ||
-		     ptype->dev == orig_or_bond)) {
+		if (ptype->type == type &&
+		    (ptype->dev == null_or_dev || ptype->dev == skb->dev)) {
 			if (pt_prev)
 				ret = deliver_skb(skb, pt_prev, orig_dev);
 			pt_prev = ptype;