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forcedeth: implement ndo_get_stats64() API
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This commit implements the ndo_get_stats64() API for forcedeth. Since
hardware stats are being updated from different contexts (process and
timer), this commit adds synchronization. For software stats, it
relies on the u64_stats_sync.h API.

Tested:
  - 16-way SMP x86_64 ->
    RX bytes:7244556582 (7.2 GB)  TX bytes:181904254 (181.9 MB)
  - pktgen + loopback: identical rx_bytes/tx_bytes and rx_packets/tx_packets

Signed-off-by: David Decotigny <david.decotigny@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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david decotigny authored and David S. Miller committed Nov 17, 2011
1 parent 1ec4f2d commit f5d827a
Showing 1 changed file with 146 additions and 51 deletions.
197 changes: 146 additions & 51 deletions drivers/net/ethernet/nvidia/forcedeth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,8 @@
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/prefetch.h>
#include <linux/io.h>
#include <linux/u64_stats_sync.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <asm/system.h>
Expand Down Expand Up @@ -736,6 +737,16 @@ 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.
*
* Hardware stats updates are protected by hwstats_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
*
* Software stats are accessed only through 64b synchronization points
* and are not subject to other synchronization techniques (single
* update thread on the TX or RX paths).
*/

/* in dev: base, irq */
Expand All @@ -745,9 +756,10 @@ struct fe_priv {
struct net_device *dev;
struct napi_struct napi;

/* General data:
* Locking: spin_lock(&np->lock); */
/* hardware stats are updated in syscall and timer */
spinlock_t hwstats_lock;
struct nv_ethtool_stats estats;

int in_shutdown;
u32 linkspeed;
int duplex;
Expand Down Expand Up @@ -798,6 +810,12 @@ struct fe_priv {
u32 nic_poll_irq;
int rx_ring_size;

/* RX software stats */
struct u64_stats_sync swstats_rx_syncp;
u64 stat_rx_packets;
u64 stat_rx_bytes; /* not always available in HW */
u64 stat_rx_missed_errors;

/* media detection workaround.
* Locking: Within irq hander or disable_irq+spin_lock(&np->lock);
*/
Expand All @@ -820,6 +838,12 @@ struct fe_priv {
struct nv_skb_map *tx_end_flip;
int tx_stop;

/* TX software stats */
struct u64_stats_sync swstats_tx_syncp;
u64 stat_tx_packets; /* not always available in HW */
u64 stat_tx_bytes;
u64 stat_tx_dropped;

/* msi/msi-x fields */
u32 msi_flags;
struct msix_entry msi_x_entry[NV_MSI_X_MAX_VECTORS];
Expand Down Expand Up @@ -1635,11 +1659,19 @@ 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)->hwstats_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 hwstats_lock with
* spin_lock_irqsave() in calling functions. */
WARN_ONCE(in_irq(), "forcedeth: estats spin_lock(_bh) from top-half");
assert_spin_locked(&np->hwstats_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);
Expand Down Expand Up @@ -1698,40 +1730,72 @@ static void nv_get_hw_stats(struct net_device *dev)
}

/*
* 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)->hwstats_lock)
__releases(&netdev_priv(dev)->hwstats_lock)
{
struct fe_priv *np = netdev_priv(dev);
unsigned int syncp_start;

/*
* Note: because HW stats are not always available and for
* consistency reasons, the following ifconfig stats are
* managed by software: rx_bytes, tx_bytes, rx_packets and
* tx_packets. The related hardware stats reported by ethtool
* should be equivalent to these ifconfig stats, with 4
* additional bytes per packet (Ethernet FCS CRC), except for
* tx_packets when TSO kicks in.
*/

/* software stats */
do {
syncp_start = u64_stats_fetch_begin(&np->swstats_rx_syncp);
storage->rx_packets = np->stat_rx_packets;
storage->rx_bytes = np->stat_rx_bytes;
storage->rx_missed_errors = np->stat_rx_missed_errors;
} while (u64_stats_fetch_retry(&np->swstats_rx_syncp, syncp_start));

do {
syncp_start = u64_stats_fetch_begin(&np->swstats_tx_syncp);
storage->tx_packets = np->stat_tx_packets;
storage->tx_bytes = np->stat_tx_bytes;
storage->tx_dropped = np->stat_tx_dropped;
} while (u64_stats_fetch_retry(&np->swstats_tx_syncp, syncp_start));

/* If the nic supports hw counters then retrieve latest values */
if (np->driver_data & (DEV_HAS_STATISTICS_V1|DEV_HAS_STATISTICS_V2|DEV_HAS_STATISTICS_V3)) {
nv_get_hw_stats(dev);
if (np->driver_data & DEV_HAS_STATISTICS_V123) {
spin_lock_bh(&np->hwstats_lock);

/*
* Note: because HW stats are not always available and
* for consistency reasons, the following ifconfig
* stats are managed by software: rx_bytes, tx_bytes,
* rx_packets and tx_packets. The related hardware
* stats reported by ethtool should be equivalent to
* these ifconfig stats, with 4 additional bytes per
* packet (Ethernet FCS CRC).
*/
nv_update_stats(dev);

/* generic stats */
storage->rx_errors = np->estats.rx_errors_total;
storage->tx_errors = np->estats.tx_errors_total;

/* 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;

/* copy to net_device stats */
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;
/* 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->hwstats_lock);
}

return &dev->stats;
return storage;
}

/*
Expand Down Expand Up @@ -1932,8 +1996,11 @@ static void nv_drain_tx(struct net_device *dev)
np->tx_ring.ex[i].bufhigh = 0;
np->tx_ring.ex[i].buflow = 0;
}
if (nv_release_txskb(np, &np->tx_skb[i]))
dev->stats.tx_dropped++;
if (nv_release_txskb(np, &np->tx_skb[i])) {
u64_stats_update_begin(&np->swstats_tx_syncp);
np->stat_tx_dropped++;
u64_stats_update_end(&np->swstats_tx_syncp);
}
np->tx_skb[i].dma = 0;
np->tx_skb[i].dma_len = 0;
np->tx_skb[i].dma_single = 0;
Expand Down Expand Up @@ -2390,11 +2457,14 @@ static int nv_tx_done(struct net_device *dev, int limit)
if (np->desc_ver == DESC_VER_1) {
if (flags & NV_TX_LASTPACKET) {
if (flags & NV_TX_ERROR) {
if ((flags & NV_TX_RETRYERROR) && !(flags & NV_TX_RETRYCOUNT_MASK))
if ((flags & NV_TX_RETRYERROR)
&& !(flags & NV_TX_RETRYCOUNT_MASK))
nv_legacybackoff_reseed(dev);
} else {
dev->stats.tx_packets++;
dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_begin(&np->swstats_tx_syncp);
np->stat_tx_packets++;
np->stat_tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_end(&np->swstats_tx_syncp);
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
Expand All @@ -2403,11 +2473,14 @@ static int nv_tx_done(struct net_device *dev, int limit)
} else {
if (flags & NV_TX2_LASTPACKET) {
if (flags & NV_TX2_ERROR) {
if ((flags & NV_TX2_RETRYERROR) && !(flags & NV_TX2_RETRYCOUNT_MASK))
if ((flags & NV_TX2_RETRYERROR)
&& !(flags & NV_TX2_RETRYCOUNT_MASK))
nv_legacybackoff_reseed(dev);
} else {
dev->stats.tx_packets++;
dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_begin(&np->swstats_tx_syncp);
np->stat_tx_packets++;
np->stat_tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_end(&np->swstats_tx_syncp);
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
Expand Down Expand Up @@ -2441,15 +2514,18 @@ static int nv_tx_done_optimized(struct net_device *dev, int limit)

if (flags & NV_TX2_LASTPACKET) {
if (flags & NV_TX2_ERROR) {
if ((flags & NV_TX2_RETRYERROR) && !(flags & NV_TX2_RETRYCOUNT_MASK)) {
if ((flags & NV_TX2_RETRYERROR)
&& !(flags & NV_TX2_RETRYCOUNT_MASK)) {
if (np->driver_data & DEV_HAS_GEAR_MODE)
nv_gear_backoff_reseed(dev);
else
nv_legacybackoff_reseed(dev);
}
} else {
dev->stats.tx_packets++;
dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_begin(&np->swstats_tx_syncp);
np->stat_tx_packets++;
np->stat_tx_bytes += np->get_tx_ctx->skb->len;
u64_stats_update_end(&np->swstats_tx_syncp);
}

dev_kfree_skb_any(np->get_tx_ctx->skb);
Expand Down Expand Up @@ -2662,8 +2738,11 @@ 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++;
if (flags & NV_RX_MISSEDFRAME) {
u64_stats_update_begin(&np->swstats_rx_syncp);
np->stat_rx_missed_errors++;
u64_stats_update_end(&np->swstats_rx_syncp);
}
dev_kfree_skb(skb);
goto next_pkt;
}
Expand Down Expand Up @@ -2706,8 +2785,10 @@ static int nv_rx_process(struct net_device *dev, int limit)
skb_put(skb, len);
skb->protocol = eth_type_trans(skb, dev);
napi_gro_receive(&np->napi, skb);
dev->stats.rx_packets++;
dev->stats.rx_bytes += len;
u64_stats_update_begin(&np->swstats_rx_syncp);
np->stat_rx_packets++;
np->stat_rx_bytes += len;
u64_stats_update_end(&np->swstats_rx_syncp);
next_pkt:
if (unlikely(np->get_rx.orig++ == np->last_rx.orig))
np->get_rx.orig = np->first_rx.orig;
Expand Down Expand Up @@ -2790,8 +2871,10 @@ static int nv_rx_process_optimized(struct net_device *dev, int limit)
__vlan_hwaccel_put_tag(skb, vid);
}
napi_gro_receive(&np->napi, skb);
dev->stats.rx_packets++;
dev->stats.rx_bytes += len;
u64_stats_update_begin(&np->swstats_rx_syncp);
np->stat_rx_packets++;
np->stat_rx_bytes += len;
u64_stats_update_end(&np->swstats_rx_syncp);
} else {
dev_kfree_skb(skb);
}
Expand Down Expand Up @@ -4000,11 +4083,18 @@ static void nv_poll_controller(struct net_device *dev)
#endif

static void nv_do_stats_poll(unsigned long data)
__acquires(&netdev_priv(dev)->hwstats_lock)
__releases(&netdev_priv(dev)->hwstats_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->hwstats_lock)) {
nv_update_stats(dev);
spin_unlock(&np->hwstats_lock);
}

if (!np->in_shutdown)
mod_timer(&np->stats_poll,
Expand Down Expand Up @@ -4712,14 +4802,18 @@ 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)->hwstats_lock)
__releases(&netdev_priv(dev)->hwstats_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->hwstats_lock);
nv_update_stats(dev);
memcpy(buffer, &np->estats,
nv_get_sset_count(dev, ETH_SS_STATS)*sizeof(u64));
spin_unlock_bh(&np->hwstats_lock);
}

static int nv_link_test(struct net_device *dev)
Expand Down Expand Up @@ -5363,7 +5457,7 @@ 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,
Expand All @@ -5380,7 +5474,7 @@ 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,
Expand Down Expand Up @@ -5419,6 +5513,7 @@ 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->hwstats_lock);
SET_NETDEV_DEV(dev, &pci_dev->dev);

init_timer(&np->oom_kick);
Expand Down

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