Patchwork [net-next,v2,06/10] forcedeth: implement ndo_get_stats64() API

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Submitter david decotigny
Date Nov. 11, 2011, 1:31 a.m.
Message ID <a5f2ece4715268a41f331f09f95aaa63e0557421.1320974990.git.david.decotigny@google.com>
Download mbox | patch
Permalink /patch/125064/
State Deferred
Delegated to: David Miller
Headers show

Comments

david decotigny - Nov. 11, 2011, 1:31 a.m.
This commit implements the ndo_get_stats64() API for forcedeth. Since
these stats are being updated from different contexts (process and
timer), this commit adds protection (locking + atomic variables).

Tested:
  16-way SMP x86_64 ->
  RX bytes:7244556582 (7.2 GB)  TX bytes:181904254 (181.9 MB)



Signed-off-by: David Decotigny <david.decotigny@google.com>
---
 drivers/net/ethernet/nvidia/forcedeth.c |  155 +++++++++++++++++++++++--------
 1 files changed, 118 insertions(+), 37 deletions(-)

Patch

diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 1a1972b..cabc121 100644
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c
@@ -693,6 +693,21 @@  struct nv_ethtool_stats {
 #define NV_DEV_STATISTICS_V2_COUNT (NV_DEV_STATISTICS_V3_COUNT - 3)
 #define NV_DEV_STATISTICS_V1_COUNT (NV_DEV_STATISTICS_V2_COUNT - 6)
 
+/* driver statistics */
+struct nv_driver_stat {
+	atomic_t delta;  /* increase since last nv_update_stats() */
+	u64 total;  /* cumulative, requires netdev_priv(dev)->stats_lock */
+};
+
+#define NV_DRIVER_STAT_ATOMIC_INC(ptr_stat) /* atomic */ \
+	({ atomic_inc(&(ptr_stat)->delta); })
+#define NV_DRIVER_STAT_ATOMIC_ADD(ptr_stat,increment) /* atomic */	\
+	({ atomic_add((increment), &(ptr_stat)->delta); })
+#define NV_DRIVER_STAT_UPDATE_TOTAL(ptr_stat) /* requires stats_lock */ \
+	({ (ptr_stat)->total += atomic_xchg(&(ptr_stat)->delta, 0); })
+#define NV_DRIVER_STAT_GET_TOTAL(ptr_stat) /* requires stats_lock */ \
+	((ptr_stat)->total)
+
 /* diagnostics */
 #define NV_TEST_COUNT_BASE 3
 #define NV_TEST_COUNT_EXTENDED 4
@@ -737,6 +752,12 @@  struct nv_skb_map {
  * - tx setup is lockless: it relies on netif_tx_lock. Actual submission
  *	needs netdev_priv(dev)->lock :-(
  * - set_multicast_list: preparation lockless, relies on netif_tx_lock.
+ *
+ * Stats are protected with stats_lock:
+ * - updated by nv_do_stats_poll (timer). This is meant to avoid
+ *   integer wraparound in the NIC stats registers, at low frequency
+ *   (0.1 Hz)
+ * - updated by nv_get_ethtool_stats + nv_get_stats64
  */
 
 /* in dev: base, irq */
@@ -746,9 +767,10 @@  struct fe_priv {
 	struct net_device *dev;
 	struct napi_struct napi;
 
-	/* General data:
-	 * Locking: spin_lock(&np->lock); */
+	/* stats are updated in syscall and timer */
+	spinlock_t stats_lock;
 	struct nv_ethtool_stats estats;
+
 	int in_shutdown;
 	u32 linkspeed;
 	int duplex;
@@ -799,6 +821,10 @@  struct fe_priv {
 	u32 nic_poll_irq;
 	int rx_ring_size;
 
+	/* RX software stats */
+	struct nv_driver_stat stat_rx_bytes; /* not always available in HW */
+	struct nv_driver_stat stat_rx_missed_errors;
+
 	/* media detection workaround.
 	 * Locking: Within irq hander or disable_irq+spin_lock(&np->lock);
 	 */
@@ -821,6 +847,10 @@  struct fe_priv {
 	struct nv_skb_map *tx_end_flip;
 	int tx_stop;
 
+	/* TX software stats */
+	struct nv_driver_stat stat_tx_packets; /* not always available in HW */
+	struct nv_driver_stat stat_tx_dropped;
+
 	/* msi/msi-x fields */
 	u32 msi_flags;
 	struct msix_entry msi_x_entry[NV_MSI_X_MAX_VECTORS];
@@ -1636,11 +1666,19 @@  static void nv_mac_reset(struct net_device *dev)
 	pci_push(base);
 }
 
-static void nv_get_hw_stats(struct net_device *dev)
+/* Caller must appropriately lock netdev_priv(dev)->stats_lock */
+static void nv_update_stats(struct net_device *dev)
 {
 	struct fe_priv *np = netdev_priv(dev);
 	u8 __iomem *base = get_hwbase(dev);
 
+	/* If it happens that this is run in top-half context, then
+	 * replace the spin_lock of stats_lock with
+	 * spin_lock_irqsave() in calling functions. */
+	WARN_ONCE(in_irq(), "forcedeth: estats spin_lock(_bh) from top-half");
+	assert_spin_locked(&np->stats_lock);
+
+	/* query hardware */
 	np->estats.tx_bytes += readl(base + NvRegTxCnt);
 	np->estats.tx_zero_rexmt += readl(base + NvRegTxZeroReXmt);
 	np->estats.tx_one_rexmt += readl(base + NvRegTxOneReXmt);
@@ -1696,44 +1734,75 @@  static void nv_get_hw_stats(struct net_device *dev)
 		np->estats.tx_multicast += readl(base + NvRegTxMulticast);
 		np->estats.tx_broadcast += readl(base + NvRegTxBroadcast);
 	}
+
+	/* update software stats */
+	NV_DRIVER_STAT_UPDATE_TOTAL(&np->stat_rx_bytes);
+	NV_DRIVER_STAT_UPDATE_TOTAL(&np->stat_rx_missed_errors);
+
+	NV_DRIVER_STAT_UPDATE_TOTAL(&np->stat_tx_packets);
+	NV_DRIVER_STAT_UPDATE_TOTAL(&np->stat_tx_dropped);
 }
 
 /*
- * nv_get_stats: dev->get_stats function
+ * nv_get_stats64: dev->ndo_get_stats64 function
  * Get latest stats value from the nic.
  * Called with read_lock(&dev_base_lock) held for read -
  * only synchronized against unregister_netdevice.
  */
-static struct net_device_stats *nv_get_stats(struct net_device *dev)
+static struct rtnl_link_stats64*
+nv_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *storage)
+	__acquires(&netdev_priv(dev)->stats_lock)
+	__releases(&netdev_priv(dev)->stats_lock)
 {
 	struct fe_priv *np = netdev_priv(dev);
 
 	/* If the nic supports hw counters then retrieve latest values */
 	if (np->driver_data & DEV_HAS_STATISTICS_V123) {
-		/* query hardware */
-		nv_get_hw_stats(dev);
+		spin_lock_bh(&np->stats_lock);
 
-		/* copy to net_device stats */
+		nv_update_stats(dev);
+
+		/* generic stats */
 
 		if (np->driver_data & DEV_HAS_STATISTICS_V23) {
 			/* When HW stats are available for following
 			 * stats, we use them. Otherwise they are
 			 * updated by software. */
-			dev->stats.tx_packets = np->estats.tx_packets;
-			dev->stats.rx_bytes = np->estats.rx_bytes;
+			storage->tx_packets = np->estats.tx_packets;
+			storage->rx_bytes   = np->estats.rx_bytes;
+		} else {
+			storage->tx_packets = NV_DRIVER_STAT_GET_TOTAL(
+				&np->stat_tx_packets);
+			storage->rx_bytes   = NV_DRIVER_STAT_GET_TOTAL(
+				&np->stat_rx_bytes);
 		}
-		dev->stats.rx_packets = np->estats.rx_packets;
-		dev->stats.tx_bytes = np->estats.tx_bytes;
-		dev->stats.tx_fifo_errors = np->estats.tx_fifo_errors;
-		dev->stats.tx_carrier_errors = np->estats.tx_carrier_errors;
-		dev->stats.rx_crc_errors = np->estats.rx_crc_errors;
-		dev->stats.rx_over_errors = np->estats.rx_over_errors;
-		dev->stats.rx_fifo_errors = np->estats.rx_drop_frame;
-		dev->stats.rx_errors = np->estats.rx_errors_total;
-		dev->stats.tx_errors = np->estats.tx_errors_total;
-	}
-
-	return &dev->stats;
+		storage->rx_packets = np->estats.rx_packets;
+		storage->tx_bytes   = np->estats.tx_bytes;
+		storage->rx_errors  = np->estats.rx_errors_total;
+		storage->tx_errors  = np->estats.tx_errors_total;
+		storage->tx_dropped = NV_DRIVER_STAT_GET_TOTAL(
+			&np->stat_tx_dropped);
+
+		/* meaningful only when NIC supports stats v3 */
+		storage->multicast  = np->estats.rx_multicast;
+
+		/* detailed rx_errors */
+		storage->rx_length_errors = np->estats.rx_length_error;
+		storage->rx_over_errors   = np->estats.rx_over_errors;
+		storage->rx_crc_errors    = np->estats.rx_crc_errors;
+		storage->rx_frame_errors  = np->estats.rx_frame_align_error;
+		storage->rx_fifo_errors   = np->estats.rx_drop_frame;
+		storage->rx_missed_errors = NV_DRIVER_STAT_GET_TOTAL(
+			&np->stat_rx_missed_errors);
+
+		/* detailed tx_errors */
+		storage->tx_carrier_errors = np->estats.tx_carrier_errors;
+		storage->tx_fifo_errors    = np->estats.tx_fifo_errors;
+
+		spin_unlock_bh(&np->stats_lock);
+	}
+
+	return storage;
 }
 
 /*
@@ -1935,7 +2004,7 @@  static void nv_drain_tx(struct net_device *dev)
 			np->tx_ring.ex[i].buflow = 0;
 		}
 		if (nv_release_txskb(np, &np->tx_skb[i]))
-			dev->stats.tx_dropped++;
+			NV_DRIVER_STAT_ATOMIC_INC(&np->stat_tx_dropped);
 		np->tx_skb[i].dma = 0;
 		np->tx_skb[i].dma_len = 0;
 		np->tx_skb[i].dma_single = 0;
@@ -2397,7 +2466,7 @@  static int nv_tx_done(struct net_device *dev, int limit)
 						nv_legacybackoff_reseed(dev);
 				} else if (unlikely(!(np->driver_data
 						      & DEV_HAS_STATISTICS_V23))) {
-					dev->stats.tx_packets++;
+					NV_DRIVER_STAT_ATOMIC_INC(&np->stat_tx_packets);
 				}
 				dev_kfree_skb_any(np->get_tx_ctx->skb);
 				np->get_tx_ctx->skb = NULL;
@@ -2411,7 +2480,7 @@  static int nv_tx_done(struct net_device *dev, int limit)
 						nv_legacybackoff_reseed(dev);
 				} else if (unlikely(!(np->driver_data
 						      & DEV_HAS_STATISTICS_V23))) {
-					dev->stats.tx_packets++;
+					NV_DRIVER_STAT_ATOMIC_INC(&np->stat_tx_packets);
 				}
 				dev_kfree_skb_any(np->get_tx_ctx->skb);
 				np->get_tx_ctx->skb = NULL;
@@ -2453,7 +2522,7 @@  static int nv_tx_done_optimized(struct net_device *dev, int limit)
 				}
 			} else if (unlikely(!(np->driver_data
 					      & DEV_HAS_STATISTICS_V23))) {
-				dev->stats.tx_packets++;
+				NV_DRIVER_STAT_ATOMIC_INC(&np->stat_tx_packets);
 			}
 
 			dev_kfree_skb_any(np->get_tx_ctx->skb);
@@ -2667,7 +2736,7 @@  static int nv_rx_process(struct net_device *dev, int limit)
 					/* the rest are hard errors */
 					else {
 						if (flags & NV_RX_MISSEDFRAME)
-							dev->stats.rx_missed_errors++;
+							NV_DRIVER_STAT_ATOMIC_INC(&np->stat_rx_missed_errors);
 						dev_kfree_skb(skb);
 						goto next_pkt;
 					}
@@ -2711,7 +2780,7 @@  static int nv_rx_process(struct net_device *dev, int limit)
 		skb->protocol = eth_type_trans(skb, dev);
 		napi_gro_receive(&np->napi, skb);
 		if (unlikely(!(np->driver_data & DEV_HAS_STATISTICS_V23)))
-			dev->stats.rx_bytes += len;
+			NV_DRIVER_STAT_ATOMIC_ADD(&np->stat_rx_bytes, len);
 next_pkt:
 		if (unlikely(np->get_rx.orig++ == np->last_rx.orig))
 			np->get_rx.orig = np->first_rx.orig;
@@ -2796,7 +2865,7 @@  static int nv_rx_process_optimized(struct net_device *dev, int limit)
 			napi_gro_receive(&np->napi, skb);
 			if (unlikely(!(np->driver_data
 				       & DEV_HAS_STATISTICS_V23)))
-				dev->stats.rx_bytes += len;
+				NV_DRIVER_STAT_ATOMIC_ADD(&np->stat_rx_bytes, len);
 		} else {
 			dev_kfree_skb(skb);
 		}
@@ -3924,11 +3993,18 @@  static void nv_poll_controller(struct net_device *dev)
 #endif
 
 static void nv_do_stats_poll(unsigned long data)
+	__acquires(&netdev_priv(dev)->stats_lock)
+	__releases(&netdev_priv(dev)->stats_lock)
 {
 	struct net_device *dev = (struct net_device *) data;
 	struct fe_priv *np = netdev_priv(dev);
 
-	nv_get_hw_stats(dev);
+	/* If lock is currently taken, the stats are being refreshed
+	 * and hence fresh enough */
+	if (spin_trylock(&np->stats_lock)) {
+		nv_update_stats(dev);
+		spin_unlock(&np->stats_lock);
+	}
 
 	if (!np->in_shutdown)
 		mod_timer(&np->stats_poll,
@@ -4573,14 +4649,18 @@  static int nv_get_sset_count(struct net_device *dev, int sset)
 	}
 }
 
-static void nv_get_ethtool_stats(struct net_device *dev, struct ethtool_stats *estats, u64 *buffer)
+static void nv_get_ethtool_stats(struct net_device *dev,
+				 struct ethtool_stats *estats, u64 *buffer)
+	__acquires(&netdev_priv(dev)->stats_lock)
+	__releases(&netdev_priv(dev)->stats_lock)
 {
 	struct fe_priv *np = netdev_priv(dev);
 
-	/* update stats */
-	nv_get_hw_stats(dev);
-
-	memcpy(buffer, &np->estats, nv_get_sset_count(dev, ETH_SS_STATS)*sizeof(u64));
+	spin_lock_bh(&np->stats_lock);
+	nv_update_stats(dev);
+	memcpy(buffer, &np->estats,
+	       nv_get_sset_count(dev, ETH_SS_STATS)*sizeof(u64));
+	spin_unlock_bh(&np->stats_lock);
 }
 
 static int nv_link_test(struct net_device *dev)
@@ -5218,7 +5298,7 @@  static int nv_close(struct net_device *dev)
 static const struct net_device_ops nv_netdev_ops = {
 	.ndo_open		= nv_open,
 	.ndo_stop		= nv_close,
-	.ndo_get_stats		= nv_get_stats,
+	.ndo_get_stats64	= nv_get_stats64,
 	.ndo_start_xmit		= nv_start_xmit,
 	.ndo_tx_timeout		= nv_tx_timeout,
 	.ndo_change_mtu		= nv_change_mtu,
@@ -5235,7 +5315,7 @@  static const struct net_device_ops nv_netdev_ops = {
 static const struct net_device_ops nv_netdev_ops_optimized = {
 	.ndo_open		= nv_open,
 	.ndo_stop		= nv_close,
-	.ndo_get_stats		= nv_get_stats,
+	.ndo_get_stats64	= nv_get_stats64,
 	.ndo_start_xmit		= nv_start_xmit_optimized,
 	.ndo_tx_timeout		= nv_tx_timeout,
 	.ndo_change_mtu		= nv_change_mtu,
@@ -5274,6 +5354,7 @@  static int __devinit nv_probe(struct pci_dev *pci_dev, const struct pci_device_i
 	np->dev = dev;
 	np->pci_dev = pci_dev;
 	spin_lock_init(&np->lock);
+	spin_lock_init(&np->stats_lock);
 	SET_NETDEV_DEV(dev, &pci_dev->dev);
 
 	init_timer(&np->oom_kick);