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Message-Id: <1371561508-11960-2-git-send-email-amirv@mellanox.com>
Date: Tue, 18 Jun 2013 16:18:27 +0300
From: Amir Vadai <amirv@...lanox.com>
To: "David S. Miller" <davem@...emloft.net>
Cc: netdev@...r.kernel.org, Or Gerlitz <ogerlitz@...lanox.com>,
Eliezer Tamir <eliezer.tamir@...ux.intel.com>,
Eric Dumazet <edumazet@...gle.com>,
Amir Vadai <amirv@...lanox.com>
Subject: [PATCH net-next V1 1/2] net/mlx4_en: Add Low Latency Socket (LLS) support
Add basic support for LLS.
Signed-off-by: Amir Vadai <amirv@...lanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_cq.c | 3 +
drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 43 ++++++++-
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 15 ++-
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 121 +++++++++++++++++++++++++
4 files changed, 178 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 1e6c594..3e2d504 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -139,6 +139,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
if (!cq->is_tx) {
netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_rx_cq, 64);
+ napi_hash_add(&cq->napi);
napi_enable(&cq->napi);
}
@@ -162,6 +163,8 @@ void mlx4_en_deactivate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq)
{
if (!cq->is_tx) {
napi_disable(&cq->napi);
+ napi_hash_del(&cq->napi);
+ synchronize_rcu();
netif_napi_del(&cq->napi);
}
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 89c47ea..bb9847a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -38,6 +38,7 @@
#include <linux/slab.h>
#include <linux/hash.h>
#include <net/ip.h>
+#include <net/ll_poll.h>
#include <linux/mlx4/driver.h>
#include <linux/mlx4/device.h>
@@ -67,6 +68,30 @@ int mlx4_en_setup_tc(struct net_device *dev, u8 up)
return 0;
}
+#ifdef CONFIG_NET_LL_RX_POLL
+/* must be called with local_bh_disable()d */
+static int mlx4_en_low_latency_recv(struct napi_struct *napi)
+{
+ struct mlx4_en_cq *cq = container_of(napi, struct mlx4_en_cq, napi);
+ struct net_device *dev = cq->dev;
+ struct mlx4_en_priv *priv = netdev_priv(dev);
+ struct mlx4_en_rx_ring *rx_ring = &priv->rx_ring[cq->ring];
+ int done;
+
+ if (!priv->port_up)
+ return LL_FLUSH_FAILED;
+
+ if (!mlx4_en_cq_lock_poll(cq))
+ return LL_FLUSH_BUSY;
+
+ done = mlx4_en_process_rx_cq(dev, cq, 4);
+
+ mlx4_en_cq_unlock_poll(cq);
+
+ return done;
+}
+#endif /* CONFIG_NET_LL_RX_POLL */
+
#ifdef CONFIG_RFS_ACCEL
struct mlx4_en_filter {
@@ -1445,6 +1470,8 @@ int mlx4_en_start_port(struct net_device *dev)
for (i = 0; i < priv->rx_ring_num; i++) {
cq = &priv->rx_cq[i];
+ mlx4_en_cq_init_lock(cq);
+
err = mlx4_en_activate_cq(priv, cq, i);
if (err) {
en_err(priv, "Failed activating Rx CQ\n");
@@ -1694,10 +1721,19 @@ void mlx4_en_stop_port(struct net_device *dev, int detach)
/* Free RX Rings */
for (i = 0; i < priv->rx_ring_num; i++) {
+ struct mlx4_en_cq *cq = &priv->rx_cq[i];
+
+ local_bh_disable();
+ while (!mlx4_en_cq_lock_napi(cq)) {
+ pr_info("CQ %d locked\n", i);
+ mdelay(1);
+ }
+ local_bh_enable();
+
mlx4_en_deactivate_rx_ring(priv, &priv->rx_ring[i]);
- while (test_bit(NAPI_STATE_SCHED, &priv->rx_cq[i].napi.state))
+ while (test_bit(NAPI_STATE_SCHED, &cq->napi.state))
msleep(1);
- mlx4_en_deactivate_cq(priv, &priv->rx_cq[i]);
+ mlx4_en_deactivate_cq(priv, cq);
}
/* close port*/
@@ -2083,6 +2119,9 @@ static const struct net_device_ops mlx4_netdev_ops = {
#ifdef CONFIG_RFS_ACCEL
.ndo_rx_flow_steer = mlx4_en_filter_rfs,
#endif
+#ifdef CONFIG_NET_LL_RX_POLL
+ .ndo_ll_poll = mlx4_en_low_latency_recv,
+#endif
};
static const struct net_device_ops mlx4_netdev_ops_master = {
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 02aee1e..9c57581 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -31,6 +31,7 @@
*
*/
+#include <net/ll_poll.h>
#include <linux/mlx4/cq.h>
#include <linux/slab.h>
#include <linux/mlx4/qp.h>
@@ -656,8 +657,11 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
* - DIX Ethernet (type interpretation)
* - TCP/IP (v4)
* - without IP options
- * - not an IP fragment */
- if (dev->features & NETIF_F_GRO) {
+ * - not an IP fragment
+ * - no LLS polling in progress
+ */
+ if (!mlx4_en_cq_ll_polling(cq) &&
+ (dev->features & NETIF_F_GRO)) {
struct sk_buff *gro_skb = napi_get_frags(&cq->napi);
if (!gro_skb)
goto next;
@@ -737,6 +741,8 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
timestamp);
}
+ skb_mark_ll(skb, &cq->napi);
+
/* Push it up the stack */
netif_receive_skb(skb);
@@ -781,8 +787,13 @@ int mlx4_en_poll_rx_cq(struct napi_struct *napi, int budget)
struct mlx4_en_priv *priv = netdev_priv(dev);
int done;
+ if (!mlx4_en_cq_lock_napi(cq))
+ return budget;
+
done = mlx4_en_process_rx_cq(dev, cq, budget);
+ mlx4_en_cq_unlock_napi(cq);
+
/* If we used up all the quota - we're probably not done yet... */
if (done == budget)
INC_PERF_COUNTER(priv->pstats.napi_quota);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index b1f51c1..11c862e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -310,6 +310,19 @@ struct mlx4_en_cq {
u16 moder_cnt;
struct mlx4_cqe *buf;
#define MLX4_EN_OPCODE_ERROR 0x1e
+
+#ifdef CONFIG_NET_LL_RX_POLL
+ unsigned int state;
+#define MLX4_EN_CQ_STATE_IDLE 0
+#define MLX4_EN_CQ_STATE_NAPI 1 /* NAPI owns this CQ */
+#define MLX4_EN_CQ_STATE_POLL 2 /* poll owns this CQ */
+#define MLX4_CQ_LOCKED (MLX4_EN_CQ_STATE_NAPI | MLX4_EN_CQ_STATE_POLL)
+#define MLX4_EN_CQ_STATE_NAPI_YIELD 4 /* NAPI yielded this CQ */
+#define MLX4_EN_CQ_STATE_POLL_YIELD 8 /* poll yielded this CQ */
+#define CQ_YIELD (MLX4_EN_CQ_STATE_NAPI_YIELD | MLX4_EN_CQ_STATE_POLL_YIELD)
+#define CQ_USER_PEND (MLX4_EN_CQ_STATE_POLL | MLX4_EN_CQ_STATE_POLL_YIELD)
+ spinlock_t poll_lock; /* protects from LLS/napi conflicts */
+#endif /* CONFIG_NET_LL_RX_POLL */
};
struct mlx4_en_port_profile {
@@ -562,6 +575,114 @@ struct mlx4_mac_entry {
struct rcu_head rcu;
};
+#ifdef CONFIG_NET_LL_RX_POLL
+static inline void mlx4_en_cq_init_lock(struct mlx4_en_cq *cq)
+{
+ spin_lock_init(&cq->poll_lock);
+ cq->state = MLX4_EN_CQ_STATE_IDLE;
+}
+
+/* called from the device poll rutine to get ownership of a cq */
+static inline bool mlx4_en_cq_lock_napi(struct mlx4_en_cq *cq)
+{
+ int rc = true;
+ spin_lock(&cq->poll_lock);
+ if (cq->state & MLX4_CQ_LOCKED) {
+ WARN_ON(cq->state & MLX4_EN_CQ_STATE_NAPI);
+ cq->state |= MLX4_EN_CQ_STATE_NAPI_YIELD;
+ rc = false;
+ } else
+ /* we don't care if someone yielded */
+ cq->state = MLX4_EN_CQ_STATE_NAPI;
+ spin_unlock(&cq->poll_lock);
+ return rc;
+}
+
+/* returns true is someone tried to get the cq while napi had it */
+static inline bool mlx4_en_cq_unlock_napi(struct mlx4_en_cq *cq)
+{
+ int rc = false;
+ spin_lock(&cq->poll_lock);
+ WARN_ON(cq->state & (MLX4_EN_CQ_STATE_POLL |
+ MLX4_EN_CQ_STATE_NAPI_YIELD));
+
+ if (cq->state & MLX4_EN_CQ_STATE_POLL_YIELD)
+ rc = true;
+ cq->state = MLX4_EN_CQ_STATE_IDLE;
+ spin_unlock(&cq->poll_lock);
+ return rc;
+}
+
+/* called from mlx4_en_low_latency_poll() */
+static inline bool mlx4_en_cq_lock_poll(struct mlx4_en_cq *cq)
+{
+ int rc = true;
+ spin_lock_bh(&cq->poll_lock);
+ if ((cq->state & MLX4_CQ_LOCKED)) {
+ struct net_device *dev = cq->dev;
+ struct mlx4_en_priv *priv = netdev_priv(dev);
+ struct mlx4_en_rx_ring *rx_ring = &priv->rx_ring[cq->ring];
+
+ cq->state |= MLX4_EN_CQ_STATE_POLL_YIELD;
+ rc = false;
+ } else
+ /* preserve yield marks */
+ cq->state |= MLX4_EN_CQ_STATE_POLL;
+ spin_unlock_bh(&cq->poll_lock);
+ return rc;
+}
+
+/* returns true if someone tried to get the cq while it was locked */
+static inline bool mlx4_en_cq_unlock_poll(struct mlx4_en_cq *cq)
+{
+ int rc = false;
+ spin_lock_bh(&cq->poll_lock);
+ WARN_ON(cq->state & (MLX4_EN_CQ_STATE_NAPI));
+
+ if (cq->state & MLX4_EN_CQ_STATE_POLL_YIELD)
+ rc = true;
+ cq->state = MLX4_EN_CQ_STATE_IDLE;
+ spin_unlock_bh(&cq->poll_lock);
+ return rc;
+}
+
+/* true if a socket is polling, even if it did not get the lock */
+static inline bool mlx4_en_cq_ll_polling(struct mlx4_en_cq *cq)
+{
+ WARN_ON(!(cq->state & MLX4_CQ_LOCKED));
+ return cq->state & CQ_USER_PEND;
+}
+#else
+static inline void mlx4_en_cq_init_lock(struct mlx4_en_cq *cq)
+{
+}
+
+static inline bool mlx4_en_cq_lock_napi(struct mlx4_en_cq *cq)
+{
+ return true;
+}
+
+static inline bool mlx4_en_cq_unlock_napi(struct mlx4_en_cq *cq)
+{
+ return false;
+}
+
+static inline bool mlx4_en_cq_lock_poll(struct mlx4_en_cq *cq)
+{
+ return false;
+}
+
+static inline bool mlx4_en_cq_unlock_poll(struct mlx4_en_cq *cq)
+{
+ return false;
+}
+
+static inline bool mlx4_en_cq_ll_polling(struct mlx4_en_cq *cq)
+{
+ return false;
+}
+#endif /* CONFIG_NET_LL_RX_POLL */
+
#define MLX4_EN_WOL_DO_MODIFY (1ULL << 63)
void mlx4_en_update_loopback_state(struct net_device *dev,
--
1.8.3.251.g1462b67
--
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