-----Original Message-----
From: Eric Dumazet [mailto:eric.dumazet@gmail.com]
Sent: Monday, October 11, 2010 5:17 AM
To: David Miller; Waskiewicz Jr, Peter P; Tantilov, Emil S; Kirsher,
Jeffrey T
Cc: netdev
Subject: [PATCH net-next] ixgbe: fix stats handling

Hi

I am sending this patch for Intel people review/test and acknowledge.

Thanks !

[PATCH net-next] ixgbe: fix stats handling

Current ixgbe stats have following problems :

- Not 64 bit safe (on 32bit arches)

- Not safe in ixgbe_clean_rx_irq() :
  All cpus dirty a common location (netdev->stats.rx_bytes &
netdev->stats.rx_packets) without proper synchronization.
  This slow down a bit multiqueue operations, and possibly miss some
updates.

Fixes :

Implement ndo_get_stats64() method to provide accurate 64bit rx|tx
bytes/packets counters, using 64bit safe infrastructure.

ixgbe_get_ethtool_stats() also use this infrastructure to provide 64bit
safe counters.

Signed-off-by: Eric Dumazet <redacted>
CC: Peter Waskiewicz <redacted>
CC: Emil Tantilov <redacted>
CC: Jeff Kirsher <redacted>
---
drivers/net/ixgbe/ixgbe.h         |    3 +-
drivers/net/ixgbe/ixgbe_ethtool.c |   29 +++++++++++---------
drivers/net/ixgbe/ixgbe_main.c    |   40 +++++++++++++++++++++++++---
3 files changed, 56 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index a8c47b0..944d9e2 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h

@@ -180,8 +180,9 @@ struct ixgbe_ring {

					 */

	struct ixgbe_queue_stats stats;
-	unsigned long reinit_state;
+	struct u64_stats_sync syncp;
	int numa_node;
+	unsigned long reinit_state;
	u64 rsc_count;			/* stat for coalesced packets */
	u64 rsc_flush;			/* stats for flushed packets */
	u32 restart_queue;		/* track tx queue restarts */

diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c

b/drivers/net/ixgbe/ixgbe_ethtool.c
index d4ac943..3c7f15d 100644

--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c

@@ -999,12 +999,11 @@ static void ixgbe_get_ethtool_stats(struct net_device

*netdev,
                                    struct ethtool_stats *stats, u64
*data)
{
	struct ixgbe_adapter *adapter = netdev_priv(netdev);
-	u64 *queue_stat;
-	int stat_count = sizeof(struct ixgbe_queue_stats) / sizeof(u64);
	struct rtnl_link_stats64 temp;
	const struct rtnl_link_stats64 *net_stats;
-	int j, k;
-	int i;
+	unsigned int start;
+	struct ixgbe_ring *ring;
+	int i, j;
	char *p = NULL;

	ixgbe_update_stats(adapter);

@@ -1025,16 +1024,22 @@ static void ixgbe_get_ethtool_stats(struct

net_device *netdev,
		           sizeof(u64)) ? *(u64 *)p : *(u32 *)p;
	}
	for (j = 0; j < adapter->num_tx_queues; j++) {
-		queue_stat = (u64 *)&adapter->tx_ring[j]->stats;
-		for (k = 0; k < stat_count; k++)
-			data[i + k] = queue_stat[k];
-		i += k;
+		ring = adapter->tx_ring[j];
+		do {
+			start = u64_stats_fetch_begin_bh(&ring->syncp);
+			data[i]   = ring->stats.packets;
+			data[i+1] = ring->stats.bytes;
+		} while (u64_stats_fetch_retry_bh(&ring->syncp, start));
+		i += 2;
	}
	for (j = 0; j < adapter->num_rx_queues; j++) {
-		queue_stat = (u64 *)&adapter->rx_ring[j]->stats;
-		for (k = 0; k < stat_count; k++)
-			data[i + k] = queue_stat[k];
-		i += k;
+		ring = adapter->rx_ring[j];
+		do {
+			start = u64_stats_fetch_begin_bh(&ring->syncp);
+			data[i]   = ring->stats.packets;
+			data[i+1] = ring->stats.bytes;
+		} while (u64_stats_fetch_retry_bh(&ring->syncp, start));
+		i += 2;
	}
	if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
		for (j = 0; j < MAX_TX_PACKET_BUFFERS; j++) {

diff --git a/drivers/net/ixgbe/ixgbe_main.c

b/drivers/net/ixgbe/ixgbe_main.c
index 95dbf60..1efbcde 100644

--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c

@@ -824,8 +824,10 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector

*q_vector,

	tx_ring->total_bytes += total_bytes;
	tx_ring->total_packets += total_packets;
+	u64_stats_update_begin(&tx_ring->syncp);
	tx_ring->stats.packets += total_packets;
	tx_ring->stats.bytes += total_bytes;
+	u64_stats_update_end(&tx_ring->syncp);
	return count < tx_ring->work_limit;
}

@@ -1172,7 +1174,6 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector

*q_vector,
			       int *work_done, int work_to_do)
{
	struct ixgbe_adapter *adapter = q_vector->adapter;
-	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;
	union ixgbe_adv_rx_desc *rx_desc, *next_rxd;
	struct ixgbe_rx_buffer *rx_buffer_info, *next_buffer;

@@ -1298,8 +1299,10 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector

*q_vector,
					rx_ring->rsc_count++;
				rx_ring->rsc_flush++;
			}
+			u64_stats_update_begin(&rx_ring->syncp);
			rx_ring->stats.packets++;
			rx_ring->stats.bytes += skb->len;
+			u64_stats_update_end(&rx_ring->syncp);
		} else {
			if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED) {
				rx_buffer_info->skb = next_buffer->skb;

@@ -1375,8 +1378,6 @@ next_desc:

	rx_ring->total_packets += total_rx_packets;
	rx_ring->total_bytes += total_rx_bytes;
-	netdev->stats.rx_bytes += total_rx_bytes;
-	netdev->stats.rx_packets += total_rx_packets;

	return cleaned;
}

@@ -6559,6 +6560,38 @@ static void ixgbe_netpoll(struct net_device *netdev)

}
#endif

+static struct rtnl_link_stats64 *ixgbe_get_stats64(struct net_device
*netdev,
+						   struct rtnl_link_stats64 *stats)
+{
+	struct ixgbe_adapter *adapter = netdev_priv(netdev);
+	int i;
+
+	/* accurate rx/tx bytes/packets stats */
+	dev_txq_stats_fold(netdev, stats);
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		struct ixgbe_ring *ring = adapter->rx_ring[i];
+		u64 bytes, packets;
+		unsigned int start;
+
+		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->rx_packets += packets;
+		stats->rx_bytes   += bytes;
+	}
+
+	/* following stats updated by ixgbe_watchdog_task() */
+	stats->multicast	= netdev->stats.multicast;
+	stats->rx_errors	= netdev->stats.rx_errors;
+	stats->rx_length_errors	= netdev->stats.rx_length_errors;
+	stats->rx_crc_errors	= netdev->stats.rx_crc_errors;
+	stats->rx_missed_errors	= netdev->stats.rx_missed_errors;
+	return stats;
+}
+
+
static const struct net_device_ops ixgbe_netdev_ops = {
	.ndo_open		= ixgbe_open,
	.ndo_stop		= ixgbe_close,

@@ -6578,6 +6611,7 @@ static const struct net_device_ops ixgbe_netdev_ops =

{
	.ndo_set_vf_vlan	= ixgbe_ndo_set_vf_vlan,
	.ndo_set_vf_tx_rate	= ixgbe_ndo_set_vf_bw,
	.ndo_get_vf_config	= ixgbe_ndo_get_vf_config,
+	.ndo_get_stats64	= ixgbe_get_stats64,
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= ixgbe_netpoll,
#endif