[PATCH] forcdeth: revised NAPI support

Revised version of the forcedeth NAPI support.
This version is based against netdev-2.6#upstream
(after the MAC patches from Ayaz today).

Can't use nv_disable_hw_interrupts because NAPI only wants to
mask off receive irq's and leave the others alone.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 140 insertions, 16 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 3a0d80b28503..ecfbd1c2408c 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -1411,6 +1411,22 @@ config FORCEDETH
           <file:Documentation/networking/net-modules.txt>.  The module will be
           called forcedeth.
 
+config FORCEDETH_NAPI
+        bool "Use Rx and Tx Polling (NAPI) (EXPERIMENTAL)"
+        depends on FORCEDETH && EXPERIMENTAL
+        help
+          NAPI is a new driver API designed to reduce CPU and interrupt load
+          when the driver is receiving lots of packets from the card. It is
+          still somewhat experimental and thus not yet enabled by default.
+
+          If your estimated Rx load is 10kpps or more, or if the card will be
+          deployed on potentially unfriendly networks (e.g. in a firewall),
+          then say Y here.
+
+          See <file:Documentation/networking/NAPI_HOWTO.txt> for more
+          information.
+
+          If in doubt, say N.
 
 config CS89x0
         tristate "CS89x0 support"
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 26fc00a9ff83..a2aca92e8b2a 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -121,6 +121,11 @@
  * DEV_NEED_TIMERIRQ will not harm you on sane hardware, only generating a few
  * superfluous timer interrupts from the nic.
  */
+#ifdef CONFIG_FORCEDETH_NAPI
+#define DRIVERNAPI "-NAPI"
+#else
+#define DRIVERNAPI
+#endif
 #define FORCEDETH_VERSION               "0.57"
 #define DRV_NAME                        "forcedeth"
 
@@ -1279,6 +1284,16 @@ static int nv_alloc_rx(struct net_device *dev)
         return 0;
 }
 
+/* If rx bufs are exhausted called after 50ms to attempt to refresh */
+#ifdef CONFIG_FORCEDETH_NAPI
+static void nv_do_rx_refill(unsigned long data)
+{
+        struct net_device *dev = (struct net_device *) data;
+
+        /* Just reschedule NAPI rx processing */
+        netif_rx_schedule(dev);
+}
+#else
 static void nv_do_rx_refill(unsigned long data)
 {
         struct net_device *dev = (struct net_device *) data;
@@ -1307,6 +1322,7 @@ static void nv_do_rx_refill(unsigned long data)
                 enable_irq(np->msi_x_entry[NV_MSI_X_VECTOR_RX].vector);
         }
 }
+#endif
 
 static void nv_init_rx(struct net_device *dev)
 {
@@ -1742,13 +1758,14 @@ static int nv_getlen(struct net_device *dev, void *packet, int datalen)
         }
 }
 
-static void nv_rx_process(struct net_device *dev)
+static int nv_rx_process(struct net_device *dev, int limit)
 {
         struct fe_priv *np = netdev_priv(dev);
         u32 flags;
         u32 vlanflags = 0;
+        int count;
 
-        for (;;) {
+        for (count = 0; count < limit; ++count) {
                 struct sk_buff *skb;
                 int len;
                 int i;
@@ -1882,17 +1899,27 @@ static void nv_rx_process(struct net_device *dev)
                 skb->protocol = eth_type_trans(skb, dev);
                 dprintk(KERN_DEBUG "%s: nv_rx_process: packet %d with %d bytes, proto %d accepted.\n",
                                         dev->name, np->cur_rx, len, skb->protocol);
-                if (np->vlangrp && (vlanflags & NV_RX3_VLAN_TAG_PRESENT)) {
-                        vlan_hwaccel_rx(skb, np->vlangrp, vlanflags & NV_RX3_VLAN_TAG_MASK);
-                } else {
+#ifdef CONFIG_FORCEDETH_NAPI
+                if (np->vlangrp && (vlanflags & NV_RX3_VLAN_TAG_PRESENT))
+                        vlan_hwaccel_receive_skb(skb, np->vlangrp,
+                                                 vlanflags & NV_RX3_VLAN_TAG_MASK);
+                else
+                        netif_receive_skb(skb);
+#else
+                if (np->vlangrp && (vlanflags & NV_RX3_VLAN_TAG_PRESENT))
+                        vlan_hwaccel_rx(skb, np->vlangrp,
+                                        vlanflags & NV_RX3_VLAN_TAG_MASK);
+                else
                         netif_rx(skb);
-                }
+#endif
                 dev->last_rx = jiffies;
                 np->stats.rx_packets++;
                 np->stats.rx_bytes += len;
 next_pkt:
                 np->cur_rx++;
         }
+
+        return count;
 }
 
 static void set_bufsize(struct net_device *dev)
@@ -2378,14 +2405,6 @@ static irqreturn_t nv_nic_irq(int foo, void *data, struct pt_regs *regs)
                 nv_tx_done(dev);
                 spin_unlock(&np->lock);
 
-                nv_rx_process(dev);
-                if (nv_alloc_rx(dev)) {
-                        spin_lock(&np->lock);
-                        if (!np->in_shutdown)
-                                mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
-                        spin_unlock(&np->lock);
-                }
-
                 if (events & NVREG_IRQ_LINK) {
                         spin_lock(&np->lock);
                         nv_link_irq(dev);
@@ -2405,6 +2424,29 @@ static irqreturn_t nv_nic_irq(int foo, void *data, struct pt_regs *regs)
                         printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
                                                 dev->name, events);
                 }
+#ifdef CONFIG_FORCEDETH_NAPI
+                if (events & NVREG_IRQ_RX_ALL) {
+                        netif_rx_schedule(dev);
+
+                        /* Disable furthur receive irq's */
+                        spin_lock(&np->lock);
+                        np->irqmask &= ~NVREG_IRQ_RX_ALL;
+
+                        if (np->msi_flags & NV_MSI_X_ENABLED)
+                                writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+                        else
+                                writel(np->irqmask, base + NvRegIrqMask);
+                        spin_unlock(&np->lock);
+                }
+#else
+                nv_rx_process(dev, dev->weight);
+                if (nv_alloc_rx(dev)) {
+                        spin_lock(&np->lock);
+                        if (!np->in_shutdown)
+                                mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
+                        spin_unlock(&np->lock);
+                }
+#endif
                 if (i > max_interrupt_work) {
                         spin_lock(&np->lock);
                         /* disable interrupts on the nic */
@@ -2476,6 +2518,63 @@ static irqreturn_t nv_nic_irq_tx(int foo, void *data, struct pt_regs *regs)
         return IRQ_RETVAL(i);
 }
 
+#ifdef CONFIG_FORCEDETH_NAPI
+static int nv_napi_poll(struct net_device *dev, int *budget)
+{
+        int pkts, limit = min(*budget, dev->quota);
+        struct fe_priv *np = netdev_priv(dev);
+        u8 __iomem *base = get_hwbase(dev);
+
+        pkts = nv_rx_process(dev, limit);
+
+        if (nv_alloc_rx(dev)) {
+                spin_lock_irq(&np->lock);
+                if (!np->in_shutdown)
+                        mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
+                spin_unlock_irq(&np->lock);
+        }
+
+        if (pkts < limit) {
+                /* all done, no more packets present */
+                netif_rx_complete(dev);
+
+                /* re-enable receive interrupts */
+                spin_lock_irq(&np->lock);
+                np->irqmask |= NVREG_IRQ_RX_ALL;
+                if (np->msi_flags & NV_MSI_X_ENABLED)
+                        writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+                else
+                        writel(np->irqmask, base + NvRegIrqMask);
+                spin_unlock_irq(&np->lock);
+                return 0;
+        } else {
+                /* used up our quantum, so reschedule */
+                dev->quota -= pkts;
+                *budget -= pkts;
+                return 1;
+        }
+}
+#endif
+
+#ifdef CONFIG_FORCEDETH_NAPI
+static irqreturn_t nv_nic_irq_rx(int foo, void *data, struct pt_regs *regs)
+{
+        struct net_device *dev = (struct net_device *) data;
+        u8 __iomem *base = get_hwbase(dev);
+        u32 events;
+
+        events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQ_RX_ALL;
+        writel(NVREG_IRQ_RX_ALL, base + NvRegMSIXIrqStatus);
+
+        if (events) {
+                netif_rx_schedule(dev);
+                /* disable receive interrupts on the nic */
+                writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+                pci_push(base);
+        }
+        return IRQ_HANDLED;
+}
+#else
 static irqreturn_t nv_nic_irq_rx(int foo, void *data, struct pt_regs *regs)
 {
         struct net_device *dev = (struct net_device *) data;
@@ -2494,7 +2593,7 @@ static irqreturn_t nv_nic_irq_rx(int foo, void *data, struct pt_regs *regs)
                 if (!(events & np->irqmask))
                         break;
 
-                nv_rx_process(dev);
+                nv_rx_process(dev, dev->weight);
                 if (nv_alloc_rx(dev)) {
                         spin_lock_irq(&np->lock);
                         if (!np->in_shutdown)
@@ -2516,12 +2615,12 @@ static irqreturn_t nv_nic_irq_rx(int foo, void *data, struct pt_regs *regs)
                         spin_unlock_irq(&np->lock);
                         break;
                 }
-
         }
         dprintk(KERN_DEBUG "%s: nv_nic_irq_rx completed\n", dev->name);
 
         return IRQ_RETVAL(i);
 }
+#endif
 
 static irqreturn_t nv_nic_irq_other(int foo, void *data, struct pt_regs *regs)
 {
@@ -3755,6 +3854,7 @@ static void nv_self_test(struct net_device *dev, struct ethtool_test *test, u64
         if (test->flags & ETH_TEST_FL_OFFLINE) {
                 if (netif_running(dev)) {
                         netif_stop_queue(dev);
+                        netif_poll_disable(dev);
                         netif_tx_lock_bh(dev);
                         spin_lock_irq(&np->lock);
                         nv_disable_hw_interrupts(dev, np->irqmask);
@@ -3813,6 +3913,7 @@ static void nv_self_test(struct net_device *dev, struct ethtool_test *test, u64
                         nv_start_rx(dev);
                         nv_start_tx(dev);
                         netif_start_queue(dev);
+                        netif_poll_enable(dev);
                         nv_enable_hw_interrupts(dev, np->irqmask);
                 }
         }
@@ -4016,6 +4117,8 @@ static int nv_open(struct net_device *dev)
         nv_start_rx(dev);
         nv_start_tx(dev);
         netif_start_queue(dev);
+        netif_poll_enable(dev);
+
         if (ret) {
                 netif_carrier_on(dev);
         } else {
@@ -4045,6 +4148,7 @@ static int nv_close(struct net_device *dev)
         spin_lock_irq(&np->lock);
         np->in_shutdown = 1;
         spin_unlock_irq(&np->lock);
+        netif_poll_disable(dev);
         synchronize_irq(dev->irq);
 
         del_timer_sync(&np->oom_kick);
@@ -4260,6 +4364,10 @@ static int __devinit nv_probe(struct pci_dev *pci_dev, const struct pci_device_i
 #ifdef CONFIG_NET_POLL_CONTROLLER
         dev->poll_controller = nv_poll_controller;
 #endif
+        dev->weight = 64;
+#ifdef CONFIG_FORCEDETH_NAPI
+        dev->poll = nv_napi_poll;
+#endif
         SET_ETHTOOL_OPS(dev, &ops);
         dev->tx_timeout = nv_tx_timeout;
         dev->watchdog_timeo = NV_WATCHDOG_TIMEO;