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Date: Tue, 29 Oct 2013 05:02:28 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Jacob Keller <jacob.e.keller@...el.com>, netdev@...r.kernel.org,
gospo@...hat.com, sassmann@...hat.com,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 08/11] ixgbevf: implement CONFIG_NET_RX_BUSY_POLL
From: Jacob Keller <jacob.e.keller@...el.com>
This patch enables CONFIG_NET_RX_BUSY_POLL support in the VF code. This enables
sockets which have enabled the SO_BUSY_POLL socket option to use the
ndo_busy_poll_recv operation which could result in lower latency, at the cost
of higher CPU utilization, and increased power usage. This support is similar
to how the ixgbe driver works.
Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/ixgbevf/ixgbevf.h | 109 ++++++++++++++++++++++
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 68 ++++++++++++++
2 files changed, 177 insertions(+)
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index d7837dcc..85c7560 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -38,6 +38,10 @@
#include "vf.h"
+#ifdef CONFIG_NET_RX_BUSY_POLL
+#include <net/busy_poll.h>
+#endif
+
/* wrapper around a pointer to a socket buffer,
* so a DMA handle can be stored along with the buffer */
struct ixgbevf_tx_buffer {
@@ -145,7 +149,112 @@ struct ixgbevf_q_vector {
struct napi_struct napi;
struct ixgbevf_ring_container rx, tx;
char name[IFNAMSIZ + 9];
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ unsigned int state;
+#define IXGBEVF_QV_STATE_IDLE 0
+#define IXGBEVF_QV_STATE_NAPI 1 /* NAPI owns this QV */
+#define IXGBEVF_QV_STATE_POLL 2 /* poll owns this QV */
+#define IXGBEVF_QV_STATE_DISABLED 4 /* QV is disabled */
+#define IXGBEVF_QV_OWNED (IXGBEVF_QV_STATE_NAPI | IXGBEVF_QV_STATE_POLL)
+#define IXGBEVF_QV_LOCKED (IXGBEVF_QV_OWNED | IXGBEVF_QV_STATE_DISABLED)
+#define IXGBEVF_QV_STATE_NAPI_YIELD 8 /* NAPI yielded this QV */
+#define IXGBEVF_QV_STATE_POLL_YIELD 16 /* poll yielded this QV */
+#define IXGBEVF_QV_YIELD (IXGBEVF_QV_STATE_NAPI_YIELD | IXGBEVF_QV_STATE_POLL_YIELD)
+#define IXGBEVF_QV_USER_PEND (IXGBEVF_QV_STATE_POLL | IXGBEVF_QV_STATE_POLL_YIELD)
+ spinlock_t lock;
+#endif /* CONFIG_NET_RX_BUSY_POLL */
};
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static inline void ixgbevf_qv_init_lock(struct ixgbevf_q_vector *q_vector)
+{
+
+ spin_lock_init(&q_vector->lock);
+ q_vector->state = IXGBEVF_QV_STATE_IDLE;
+}
+
+/* called from the device poll routine to get ownership of a q_vector */
+static inline bool ixgbevf_qv_lock_napi(struct ixgbevf_q_vector *q_vector)
+{
+ int rc = true;
+ spin_lock_bh(&q_vector->lock);
+ if (q_vector->state & IXGBEVF_QV_LOCKED) {
+ WARN_ON(q_vector->state & IXGBEVF_QV_STATE_NAPI);
+ q_vector->state |= IXGBEVF_QV_STATE_NAPI_YIELD;
+ rc = false;
+ } else {
+ /* we don't care if someone yielded */
+ q_vector->state = IXGBEVF_QV_STATE_NAPI;
+ }
+ spin_unlock_bh(&q_vector->lock);
+ return rc;
+}
+
+/* returns true is someone tried to get the qv while napi had it */
+static inline bool ixgbevf_qv_unlock_napi(struct ixgbevf_q_vector *q_vector)
+{
+ int rc = false;
+ spin_lock_bh(&q_vector->lock);
+ WARN_ON(q_vector->state & (IXGBEVF_QV_STATE_POLL |
+ IXGBEVF_QV_STATE_NAPI_YIELD));
+
+ if (q_vector->state & IXGBEVF_QV_STATE_POLL_YIELD)
+ rc = true;
+ /* reset state to idle, unless QV is disabled */
+ q_vector->state &= IXGBEVF_QV_STATE_DISABLED;
+ spin_unlock_bh(&q_vector->lock);
+ return rc;
+}
+
+/* called from ixgbevf_low_latency_poll() */
+static inline bool ixgbevf_qv_lock_poll(struct ixgbevf_q_vector *q_vector)
+{
+ int rc = true;
+ spin_lock_bh(&q_vector->lock);
+ if ((q_vector->state & IXGBEVF_QV_LOCKED)) {
+ q_vector->state |= IXGBEVF_QV_STATE_POLL_YIELD;
+ rc = false;
+ } else {
+ /* preserve yield marks */
+ q_vector->state |= IXGBEVF_QV_STATE_POLL;
+ }
+ spin_unlock_bh(&q_vector->lock);
+ return rc;
+}
+
+/* returns true if someone tried to get the qv while it was locked */
+static inline bool ixgbevf_qv_unlock_poll(struct ixgbevf_q_vector *q_vector)
+{
+ int rc = false;
+ spin_lock_bh(&q_vector->lock);
+ WARN_ON(q_vector->state & (IXGBEVF_QV_STATE_NAPI));
+
+ if (q_vector->state & IXGBEVF_QV_STATE_POLL_YIELD)
+ rc = true;
+ /* reset state to idle, unless QV is disabled */
+ q_vector->state &= IXGBEVF_QV_STATE_DISABLED;
+ spin_unlock_bh(&q_vector->lock);
+ return rc;
+}
+
+/* true if a socket is polling, even if it did not get the lock */
+static inline bool ixgbevf_qv_busy_polling(struct ixgbevf_q_vector *q_vector)
+{
+ WARN_ON(!(q_vector->state & IXGBEVF_QV_OWNED));
+ return q_vector->state & IXGBEVF_QV_USER_PEND;
+}
+
+/* false if QV is currently owned */
+static inline bool ixgbevf_qv_disable(struct ixgbevf_q_vector *q_vector)
+{
+ int rc = true;
+ spin_lock_bh(&q_vector->lock);
+ if (q_vector->state & IXGBEVF_QV_OWNED)
+ rc = false;
+ spin_unlock_bh(&q_vector->lock);
+ return rc;
+}
+
+#endif /* CONFIG_NET_RX_BUSY_POLL */
/*
* microsecond values for various ITR rates shifted by 2 to fit itr register
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 06e29bd..bc03a2e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -310,6 +310,16 @@ static void ixgbevf_rx_skb(struct ixgbevf_q_vector *q_vector,
struct sk_buff *skb, u8 status,
union ixgbe_adv_rx_desc *rx_desc)
{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ skb_mark_napi_id(skb, &q_vector->napi);
+
+ if (ixgbevf_qv_busy_polling(q_vector)) {
+ netif_receive_skb(skb);
+ /* exit early if we busy polled */
+ return;
+ }
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
ixgbevf_receive_skb(q_vector, skb, status, rx_desc);
}
@@ -563,6 +573,11 @@ static int ixgbevf_poll(struct napi_struct *napi, int budget)
ixgbevf_for_each_ring(ring, q_vector->tx)
clean_complete &= ixgbevf_clean_tx_irq(q_vector, ring);
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ if (!ixgbevf_qv_lock_napi(q_vector))
+ return budget;
+#endif
+
/* attempt to distribute budget to each queue fairly, but don't allow
* the budget to go below 1 because we'll exit polling */
if (q_vector->rx.count > 1)
@@ -577,6 +592,10 @@ static int ixgbevf_poll(struct napi_struct *napi, int budget)
< per_ring_budget);
adapter->flags &= ~IXGBE_FLAG_IN_NETPOLL;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ ixgbevf_qv_unlock_napi(q_vector);
+#endif
+
/* If all work not completed, return budget and keep polling */
if (!clean_complete)
return budget;
@@ -611,6 +630,34 @@ void ixgbevf_write_eitr(struct ixgbevf_q_vector *q_vector)
IXGBE_WRITE_REG(hw, IXGBE_VTEITR(v_idx), itr_reg);
}
+#ifdef CONFIG_NET_RX_BUSY_POLL
+/* must be called with local_bh_disable()d */
+static int ixgbevf_busy_poll_recv(struct napi_struct *napi)
+{
+ struct ixgbevf_q_vector *q_vector =
+ container_of(napi, struct ixgbevf_q_vector, napi);
+ struct ixgbevf_adapter *adapter = q_vector->adapter;
+ struct ixgbevf_ring *ring;
+ int found = 0;
+
+ if (test_bit(__IXGBEVF_DOWN, &adapter->state))
+ return LL_FLUSH_FAILED;
+
+ if (!ixgbevf_qv_lock_poll(q_vector))
+ return LL_FLUSH_BUSY;
+
+ ixgbevf_for_each_ring(ring, q_vector->rx) {
+ found = ixgbevf_clean_rx_irq(q_vector, ring, 4);
+ if (found)
+ break;
+ }
+
+ ixgbevf_qv_unlock_poll(q_vector);
+
+ return found;
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
/**
* ixgbevf_configure_msix - Configure MSI-X hardware
* @adapter: board private structure
@@ -1297,6 +1344,9 @@ static void ixgbevf_napi_enable_all(struct ixgbevf_adapter *adapter)
for (q_idx = 0; q_idx < q_vectors; q_idx++) {
q_vector = adapter->q_vector[q_idx];
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ ixgbevf_qv_init_lock(adapter->q_vector[q_idx]);
+#endif
napi_enable(&q_vector->napi);
}
}
@@ -1310,6 +1360,12 @@ static void ixgbevf_napi_disable_all(struct ixgbevf_adapter *adapter)
for (q_idx = 0; q_idx < q_vectors; q_idx++) {
q_vector = adapter->q_vector[q_idx];
napi_disable(&q_vector->napi);
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ while (!ixgbevf_qv_disable(adapter->q_vector[q_idx])) {
+ pr_info("QV %d locked\n", q_idx);
+ usleep_range(1000, 20000);
+ }
+#endif /* CONFIG_NET_RX_BUSY_POLL */
}
}
@@ -1960,6 +2016,9 @@ static int ixgbevf_alloc_q_vectors(struct ixgbevf_adapter *adapter)
q_vector->v_idx = q_idx;
netif_napi_add(adapter->netdev, &q_vector->napi,
ixgbevf_poll, 64);
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ napi_hash_add(&q_vector->napi);
+#endif
adapter->q_vector[q_idx] = q_vector;
}
@@ -1969,6 +2028,9 @@ err_out:
while (q_idx) {
q_idx--;
q_vector = adapter->q_vector[q_idx];
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ napi_hash_del(&q_vector->napi);
+#endif
netif_napi_del(&q_vector->napi);
kfree(q_vector);
adapter->q_vector[q_idx] = NULL;
@@ -1992,6 +2054,9 @@ static void ixgbevf_free_q_vectors(struct ixgbevf_adapter *adapter)
struct ixgbevf_q_vector *q_vector = adapter->q_vector[q_idx];
adapter->q_vector[q_idx] = NULL;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ napi_hash_del(&q_vector->napi);
+#endif
netif_napi_del(&q_vector->napi);
kfree(q_vector);
}
@@ -3323,6 +3388,9 @@ static const struct net_device_ops ixgbevf_netdev_ops = {
.ndo_tx_timeout = ixgbevf_tx_timeout,
.ndo_vlan_rx_add_vid = ixgbevf_vlan_rx_add_vid,
.ndo_vlan_rx_kill_vid = ixgbevf_vlan_rx_kill_vid,
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ .ndo_busy_poll = ixgbevf_busy_poll_recv,
+#endif
};
static void ixgbevf_assign_netdev_ops(struct net_device *dev)
--
1.8.3.1
--
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