Thread (7 messages) 7 messages, 4 authors, 2011-01-12
STALE5632d

[PATCH] net: remove dev_txq_stats_fold()

From: Eric Dumazet <hidden>
Date: 2011-01-12 15:02:05
Subsystem: networking drivers, networking [general], tc subsystem, the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds

Possibly related (same subject, not in this thread)

Le mercredi 12 janvier 2011 à 14:52 +0100, Eric Dumazet a écrit :
Or even better, remove these counters since there is no users left but
ixgbe.

(vlans, tunnels, ... now use percpu stats)
Thanks Jarek for the reminder :)

[PATCH] net: remove dev_txq_stats_fold()

After recent changes, (percpu stats on vlan/tunnels...), we dont need
anymore per struct netdev_queue tx_bytes/tx_packets/tx_dropped counters.

Only remaining users are ixgbe, sch_teql & macvlan :

1) ixgbe can be converted to use existing tx_ring counters.

2) macvlan incremented txq->tx_dropped, it can use the
dev->stats.tx_dropped counter.

3) sch_teql : almost revert ab35cd4b8f42 (Use net_device internal stats)
    Now we have ndo_get_stats64(), use it.

This removes a lockdep warning (and possible lockup) in rndis gadget,
calling dev_get_stats() from hard IRQ context.

Ref: http://www.spinics.net/lists/netdev/msg149202.html

Reported-by: Neil Jones <redacted>
Signed-off-by: Eric Dumazet <redacted>
CC: Jarek Poplawski <redacted>
CC: Alexander Duyck <redacted>
CC: Jeff Kirsher <redacted>
---
 drivers/net/ixgbe/ixgbe_main.c |   23 ++++++++++++++++-------
 drivers/net/macvtap.c          |    2 +-
 include/linux/netdevice.h      |    5 -----
 net/core/dev.c                 |   29 -----------------------------
 net/sched/sch_teql.c           |   26 +++++++++++++++++++++-----
 5 files changed, 38 insertions(+), 47 deletions(-)
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index a060610..602078b 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -6667,8 +6667,6 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
 			  struct ixgbe_adapter *adapter,
 			  struct ixgbe_ring *tx_ring)
 {
-	struct net_device *netdev = tx_ring->netdev;
-	struct netdev_queue *txq;
 	unsigned int first;
 	unsigned int tx_flags = 0;
 	u8 hdr_len = 0;
@@ -6765,9 +6763,6 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
 		/* add the ATR filter if ATR is on */
 		if (test_bit(__IXGBE_TX_FDIR_INIT_DONE, &tx_ring->state))
 			ixgbe_atr(tx_ring, skb, tx_flags, protocol);
-		txq = netdev_get_tx_queue(netdev, tx_ring->queue_index);
-		txq->tx_bytes += skb->len;
-		txq->tx_packets++;
 		ixgbe_tx_queue(tx_ring, tx_flags, count, skb->len, hdr_len);
 		ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED);
 
@@ -6925,8 +6920,6 @@ static struct rtnl_link_stats64 *ixgbe_get_stats64(struct net_device *netdev,
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 	int i;
 
-	/* accurate rx/tx bytes/packets stats */
-	dev_txq_stats_fold(netdev, stats);
 	rcu_read_lock();
 	for (i = 0; i < adapter->num_rx_queues; i++) {
 		struct ixgbe_ring *ring = ACCESS_ONCE(adapter->rx_ring[i]);
@@ -6943,6 +6936,22 @@ static struct rtnl_link_stats64 *ixgbe_get_stats64(struct net_device *netdev,
 			stats->rx_bytes   += bytes;
 		}
 	}
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct ixgbe_ring *ring = ACCESS_ONCE(adapter->tx_ring[i]);
+		u64 bytes, packets;
+		unsigned int start;
+
+		if (ring) {
+			do {
+				start = u64_stats_fetch_begin_bh(&ring->syncp);
+				packets = ring->stats.packets;
+				bytes   = ring->stats.bytes;
+			} while (u64_stats_fetch_retry_bh(&ring->syncp, start));
+			stats->tx_packets += packets;
+			stats->tx_bytes   += bytes;
+		}
+	}
 	rcu_read_unlock();
 	/* following stats updated by ixgbe_watchdog_task() */
 	stats->multicast	= netdev->stats.multicast;
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 21845af..5933621 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -585,7 +585,7 @@ err:
 	rcu_read_lock_bh();
 	vlan = rcu_dereference(q->vlan);
 	if (vlan)
-		netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
+		vlan->dev->stats.tx_dropped++;
 	rcu_read_unlock_bh();
 
 	return err;
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index be4957c..d971346 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -520,9 +520,6 @@ struct netdev_queue {
 	 * please use this field instead of dev->trans_start
 	 */
 	unsigned long		trans_start;
-	u64			tx_bytes;
-	u64			tx_packets;
-	u64			tx_dropped;
 } ____cacheline_aligned_in_smp;
 
 static inline int netdev_queue_numa_node_read(const struct netdev_queue *q)
@@ -2265,8 +2262,6 @@ extern void		dev_load(struct net *net, const char *name);
 extern void		dev_mcast_init(void);
 extern struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 					       struct rtnl_link_stats64 *storage);
-extern void		dev_txq_stats_fold(const struct net_device *dev,
-					   struct rtnl_link_stats64 *stats);
 
 extern int		netdev_max_backlog;
 extern int		netdev_tstamp_prequeue;
diff --git a/net/core/dev.c b/net/core/dev.c
index a3ef808..83507c2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5523,34 +5523,6 @@ void netdev_run_todo(void)
 	}
 }
 
-/**
- *	dev_txq_stats_fold - fold tx_queues stats
- *	@dev: device to get statistics from
- *	@stats: struct rtnl_link_stats64 to hold results
- */
-void dev_txq_stats_fold(const struct net_device *dev,
-			struct rtnl_link_stats64 *stats)
-{
-	u64 tx_bytes = 0, tx_packets = 0, tx_dropped = 0;
-	unsigned int i;
-	struct netdev_queue *txq;
-
-	for (i = 0; i < dev->num_tx_queues; i++) {
-		txq = netdev_get_tx_queue(dev, i);
-		spin_lock_bh(&txq->_xmit_lock);
-		tx_bytes   += txq->tx_bytes;
-		tx_packets += txq->tx_packets;
-		tx_dropped += txq->tx_dropped;
-		spin_unlock_bh(&txq->_xmit_lock);
-	}
-	if (tx_bytes || tx_packets || tx_dropped) {
-		stats->tx_bytes   = tx_bytes;
-		stats->tx_packets = tx_packets;
-		stats->tx_dropped = tx_dropped;
-	}
-}
-EXPORT_SYMBOL(dev_txq_stats_fold);
-
 /* Convert net_device_stats to rtnl_link_stats64.  They have the same
  * fields in the same order, with only the type differing.
  */
@@ -5594,7 +5566,6 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 		netdev_stats_to_stats64(storage, ops->ndo_get_stats(dev));
 	} else {
 		netdev_stats_to_stats64(storage, &dev->stats);
-		dev_txq_stats_fold(dev, storage);
 	}
 	storage->rx_dropped += atomic_long_read(&dev->rx_dropped);
 	return storage;
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index af9360d..8b82c13 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -59,6 +59,10 @@ struct teql_master
 	struct net_device *dev;
 	struct Qdisc *slaves;
 	struct list_head master_list;
+	u64	tx_bytes;
+	u64	tx_packets;
+	u64	tx_errors;
+	u64	tx_dropped;
 };
 
 struct teql_sched_data
@@ -274,7 +278,6 @@ static inline int teql_resolve(struct sk_buff *skb,
 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct teql_master *master = netdev_priv(dev);
-	struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
 	struct Qdisc *start, *q;
 	int busy;
 	int nores;
@@ -314,8 +317,8 @@ restart:
 					__netif_tx_unlock(slave_txq);
 					master->slaves = NEXT_SLAVE(q);
 					netif_wake_queue(dev);
-					txq->tx_packets++;
-					txq->tx_bytes += length;
+ 					master->tx_packets++;
+ 					master->tx_bytes += length;
 					return NETDEV_TX_OK;
 				}
 				__netif_tx_unlock(slave_txq);
@@ -342,10 +345,10 @@ restart:
 		netif_stop_queue(dev);
 		return NETDEV_TX_BUSY;
 	}
-	dev->stats.tx_errors++;
+	master->tx_errors++;
 
 drop:
-	txq->tx_dropped++;
+	master->tx_dropped++;
 	dev_kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
@@ -398,6 +401,18 @@ static int teql_master_close(struct net_device *dev)
 	return 0;
 }
 
+static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
+						     struct rtnl_link_stats64 *stats)
+{
+	struct teql_master *m = netdev_priv(dev);
+
+	stats->tx_packets	= m->tx_packets;
+	stats->tx_bytes		= m->tx_bytes;
+	stats->tx_errors	= m->tx_errors;
+	stats->tx_dropped	= m->tx_dropped;
+	return stats;
+}
+
 static int teql_master_mtu(struct net_device *dev, int new_mtu)
 {
 	struct teql_master *m = netdev_priv(dev);
@@ -422,6 +437,7 @@ static const struct net_device_ops teql_netdev_ops = {
 	.ndo_open	= teql_master_open,
 	.ndo_stop	= teql_master_close,
 	.ndo_start_xmit	= teql_master_xmit,
+	.ndo_get_stats64 = teql_master_stats64,
 	.ndo_change_mtu	= teql_master_mtu,
 };
 

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