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authorHyong-Youb Kim <hykim@myri.com>2013-08-19 02:02:19 -0700
committerDavid S. Miller <davem@davemloft.net>2013-08-20 15:05:37 -0700
commit0dde80268ee0a5a1511935bdb9c547191d616aa9 (patch)
treedbd67e401f549d480908765bd5b8ef8a11a0f3a4 /drivers
parentipv4: raise IP_MAX_MTU to theoretical limit (diff)
downloadlinux-dev-0dde80268ee0a5a1511935bdb9c547191d616aa9.tar.xz
linux-dev-0dde80268ee0a5a1511935bdb9c547191d616aa9.zip
myri10ge: Add support for ndo_busy_poll
Add the ndo_busy_poll handler. Use skb_mark_napi_id to mark receive packets with the napi id. For each slice, use per-slice spinlock and state variable to ensure that only one handler processes receive pacekts. Locking, statistics counters, and the ndo_busy_poll handler follow those in the ixgbe driver. So, credit goes to that driver's authors. Signed-off-by: Hyong-Youb Kim <hykim@myri.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/ethernet/myricom/myri10ge/myri10ge.c200
1 files changed, 198 insertions, 2 deletions
diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 66c040047da7..50a1d4a04eb0 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -74,6 +74,7 @@
#ifdef CONFIG_MTRR
#include <asm/mtrr.h>
#endif
+#include <net/busy_poll.h>
#include "myri10ge_mcp.h"
#include "myri10ge_mcp_gen_header.h"
@@ -194,6 +195,21 @@ struct myri10ge_slice_state {
int cpu;
__be32 __iomem *dca_tag;
#endif
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ unsigned int state;
+#define SLICE_STATE_IDLE 0
+#define SLICE_STATE_NAPI 1 /* NAPI owns this slice */
+#define SLICE_STATE_POLL 2 /* poll owns this slice */
+#define SLICE_LOCKED (SLICE_STATE_NAPI | SLICE_STATE_POLL)
+#define SLICE_STATE_NAPI_YIELD 4 /* NAPI yielded this slice */
+#define SLICE_STATE_POLL_YIELD 8 /* poll yielded this slice */
+#define SLICE_USER_PEND (SLICE_STATE_POLL | SLICE_STATE_POLL_YIELD)
+ spinlock_t lock;
+ unsigned long lock_napi_yield;
+ unsigned long lock_poll_yield;
+ unsigned long busy_poll_miss;
+ unsigned long busy_poll_cnt;
+#endif /* CONFIG_NET_RX_BUSY_POLL */
char irq_desc[32];
};
@@ -909,6 +925,92 @@ abort:
return status;
}
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static inline void myri10ge_ss_init_lock(struct myri10ge_slice_state *ss)
+{
+ spin_lock_init(&ss->lock);
+ ss->state = SLICE_STATE_IDLE;
+}
+
+static inline bool myri10ge_ss_lock_napi(struct myri10ge_slice_state *ss)
+{
+ int rc = true;
+ spin_lock(&ss->lock);
+ if ((ss->state & SLICE_LOCKED)) {
+ WARN_ON((ss->state & SLICE_STATE_NAPI));
+ ss->state |= SLICE_STATE_NAPI_YIELD;
+ rc = false;
+ ss->lock_napi_yield++;
+ } else
+ ss->state = SLICE_STATE_NAPI;
+ spin_unlock(&ss->lock);
+ return rc;
+}
+
+static inline void myri10ge_ss_unlock_napi(struct myri10ge_slice_state *ss)
+{
+ spin_lock(&ss->lock);
+ WARN_ON((ss->state & (SLICE_STATE_POLL | SLICE_STATE_NAPI_YIELD)));
+ ss->state = SLICE_STATE_IDLE;
+ spin_unlock(&ss->lock);
+}
+
+static inline bool myri10ge_ss_lock_poll(struct myri10ge_slice_state *ss)
+{
+ int rc = true;
+ spin_lock_bh(&ss->lock);
+ if ((ss->state & SLICE_LOCKED)) {
+ ss->state |= SLICE_STATE_POLL_YIELD;
+ rc = false;
+ ss->lock_poll_yield++;
+ } else
+ ss->state |= SLICE_STATE_POLL;
+ spin_unlock_bh(&ss->lock);
+ return rc;
+}
+
+static inline void myri10ge_ss_unlock_poll(struct myri10ge_slice_state *ss)
+{
+ spin_lock_bh(&ss->lock);
+ WARN_ON((ss->state & SLICE_STATE_NAPI));
+ ss->state = SLICE_STATE_IDLE;
+ spin_unlock_bh(&ss->lock);
+}
+
+static inline bool myri10ge_ss_busy_polling(struct myri10ge_slice_state *ss)
+{
+ WARN_ON(!(ss->state & SLICE_LOCKED));
+ return (ss->state & SLICE_USER_PEND);
+}
+#else /* CONFIG_NET_RX_BUSY_POLL */
+static inline void myri10ge_ss_init_lock(struct myri10ge_slice_state *ss)
+{
+}
+
+static inline bool myri10ge_ss_lock_napi(struct myri10ge_slice_state *ss)
+{
+ return false;
+}
+
+static inline void myri10ge_ss_unlock_napi(struct myri10ge_slice_state *ss)
+{
+}
+
+static inline bool myri10ge_ss_lock_poll(struct myri10ge_slice_state *ss)
+{
+ return false;
+}
+
+static inline void myri10ge_ss_unlock_poll(struct myri10ge_slice_state *ss)
+{
+}
+
+static inline bool myri10ge_ss_busy_polling(struct myri10ge_slice_state *ss)
+{
+ return false;
+}
+#endif
+
static int myri10ge_reset(struct myri10ge_priv *mgp)
{
struct myri10ge_cmd cmd;
@@ -1300,6 +1402,8 @@ myri10ge_vlan_rx(struct net_device *dev, void *addr, struct sk_buff *skb)
}
}
+#define MYRI10GE_HLEN 64 /* Bytes to copy from page to skb linear memory */
+
static inline int
myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum)
{
@@ -1311,6 +1415,7 @@ myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum)
struct pci_dev *pdev = mgp->pdev;
struct net_device *dev = mgp->dev;
u8 *va;
+ bool polling;
if (len <= mgp->small_bytes) {
rx = &ss->rx_small;
@@ -1325,7 +1430,15 @@ myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum)
va = page_address(rx->info[idx].page) + rx->info[idx].page_offset;
prefetch(va);
- skb = napi_get_frags(&ss->napi);
+ /* When busy polling in user context, allocate skb and copy headers to
+ * skb's linear memory ourselves. When not busy polling, use the napi
+ * gro api.
+ */
+ polling = myri10ge_ss_busy_polling(ss);
+ if (polling)
+ skb = netdev_alloc_skb(dev, MYRI10GE_HLEN + 16);
+ else
+ skb = napi_get_frags(&ss->napi);
if (unlikely(skb == NULL)) {
ss->stats.rx_dropped++;
for (i = 0, remainder = len; remainder > 0; i++) {
@@ -1364,8 +1477,29 @@ myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum)
}
myri10ge_vlan_rx(mgp->dev, va, skb);
skb_record_rx_queue(skb, ss - &mgp->ss[0]);
+ skb_mark_napi_id(skb, &ss->napi);
+
+ if (polling) {
+ int hlen;
+
+ /* myri10ge_vlan_rx might have moved the header, so compute
+ * length and address again.
+ */
+ hlen = MYRI10GE_HLEN > skb->len ? skb->len : MYRI10GE_HLEN;
+ va = page_address(skb_frag_page(&rx_frags[0])) +
+ rx_frags[0].page_offset;
+ /* Copy header into the skb linear memory */
+ skb_copy_to_linear_data(skb, va, hlen);
+ rx_frags[0].page_offset += hlen;
+ rx_frags[0].size -= hlen;
+ skb->data_len -= hlen;
+ skb->tail += hlen;
+ skb->protocol = eth_type_trans(skb, dev);
+ netif_receive_skb(skb);
+ }
+ else
+ napi_gro_frags(&ss->napi);
- napi_gro_frags(&ss->napi);
return 1;
}
@@ -1524,10 +1658,14 @@ static int myri10ge_poll(struct napi_struct *napi, int budget)
if (ss->mgp->dca_enabled)
myri10ge_update_dca(ss);
#endif
+ /* Try later if the busy_poll handler is running. */
+ if (!myri10ge_ss_lock_napi(ss))
+ return budget;
/* process as many rx events as NAPI will allow */
work_done = myri10ge_clean_rx_done(ss, budget);
+ myri10ge_ss_unlock_napi(ss);
if (work_done < budget) {
napi_complete(napi);
put_be32(htonl(3), ss->irq_claim);
@@ -1535,6 +1673,34 @@ static int myri10ge_poll(struct napi_struct *napi, int budget)
return work_done;
}
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static int myri10ge_busy_poll(struct napi_struct *napi)
+{
+ struct myri10ge_slice_state *ss =
+ container_of(napi, struct myri10ge_slice_state, napi);
+ struct myri10ge_priv *mgp = ss->mgp;
+ int work_done;
+
+ /* Poll only when the link is up */
+ if (mgp->link_state != MXGEFW_LINK_UP)
+ return LL_FLUSH_FAILED;
+
+ if (!myri10ge_ss_lock_poll(ss))
+ return LL_FLUSH_BUSY;
+
+ /* Process a small number of packets */
+ work_done = myri10ge_clean_rx_done(ss, 4);
+ if (work_done)
+ ss->busy_poll_cnt += work_done;
+ else
+ ss->busy_poll_miss++;
+
+ myri10ge_ss_unlock_poll(ss);
+
+ return work_done;
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
static irqreturn_t myri10ge_intr(int irq, void *arg)
{
struct myri10ge_slice_state *ss = arg;
@@ -1742,6 +1908,10 @@ static const char myri10ge_gstrings_slice_stats[][ETH_GSTRING_LEN] = {
"tx_pkt_start", "tx_pkt_done", "tx_req", "tx_done",
"rx_small_cnt", "rx_big_cnt",
"wake_queue", "stop_queue", "tx_linearized",
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ "rx_lock_napi_yield", "rx_lock_poll_yield", "rx_busy_poll_miss",
+ "rx_busy_poll_cnt",
+#endif
};
#define MYRI10GE_NET_STATS_LEN 21
@@ -1842,6 +2012,12 @@ myri10ge_get_ethtool_stats(struct net_device *netdev,
data[i++] = (unsigned int)ss->tx.wake_queue;
data[i++] = (unsigned int)ss->tx.stop_queue;
data[i++] = (unsigned int)ss->tx.linearized;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ data[i++] = ss->lock_napi_yield;
+ data[i++] = ss->lock_poll_yield;
+ data[i++] = ss->busy_poll_miss;
+ data[i++] = ss->busy_poll_cnt;
+#endif
}
}
@@ -2405,6 +2581,9 @@ static int myri10ge_open(struct net_device *dev)
goto abort_with_rings;
}
+ /* Initialize the slice spinlock and state used for polling */
+ myri10ge_ss_init_lock(ss);
+
/* must happen prior to any irq */
napi_enable(&(ss)->napi);
}
@@ -2481,9 +2660,19 @@ static int myri10ge_close(struct net_device *dev)
del_timer_sync(&mgp->watchdog_timer);
mgp->running = MYRI10GE_ETH_STOPPING;
+ local_bh_disable(); /* myri10ge_ss_lock_napi needs bh disabled */
for (i = 0; i < mgp->num_slices; i++) {
napi_disable(&mgp->ss[i].napi);
+ /* Lock the slice to prevent the busy_poll handler from
+ * accessing it. Later when we bring the NIC up, myri10ge_open
+ * resets the slice including this lock.
+ */
+ while (!myri10ge_ss_lock_napi(&mgp->ss[i])) {
+ pr_info("Slice %d locked\n", i);
+ mdelay(1);
+ }
}
+ local_bh_enable();
netif_carrier_off(dev);
netif_tx_stop_all_queues(dev);
@@ -3569,8 +3758,11 @@ static void myri10ge_free_slices(struct myri10ge_priv *mgp)
ss->fw_stats, ss->fw_stats_bus);
ss->fw_stats = NULL;
}
+ napi_hash_del(&ss->napi);
netif_napi_del(&ss->napi);
}
+ /* Wait till napi structs are no longer used, and then free ss. */
+ synchronize_rcu();
kfree(mgp->ss);
mgp->ss = NULL;
}
@@ -3606,6 +3798,7 @@ static int myri10ge_alloc_slices(struct myri10ge_priv *mgp)
ss->dev = mgp->dev;
netif_napi_add(ss->dev, &ss->napi, myri10ge_poll,
myri10ge_napi_weight);
+ napi_hash_add(&ss->napi);
}
return 0;
abort:
@@ -3748,6 +3941,9 @@ static const struct net_device_ops myri10ge_netdev_ops = {
.ndo_change_mtu = myri10ge_change_mtu,
.ndo_set_rx_mode = myri10ge_set_multicast_list,
.ndo_set_mac_address = myri10ge_set_mac_address,
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ .ndo_busy_poll = myri10ge_busy_poll,
+#endif
};
static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)