From c777cdfa4e69548f45078165d17828dd6711120f Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Sat, 21 Sep 2013 06:24:20 +0000 Subject: [PATCH] ixgbevf: implement CONFIG_NET_RX_BUSY_POLL 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 Tested-by: Phil Schmitt Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbevf/ixgbevf.h | 109 ++++++++++++++++++ .../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 d7837dcc9897..85c7560e237b 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 +#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 06e29bd73777..bc03a2ec5c0a 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) -- 2.20.1