[ewg] [PATCH] IB/ipoib: fix net queue lockup
Eli Cohen
eli at dev.mellanox.co.il
Wed Apr 30 10:39:16 PDT 2008
>From 1644c62982335b5cf67300ccba2533016e240d6a Mon Sep 17 00:00:00 2001
From: Eli Cohen <eli at mellanox.co.il>
Date: Wed, 30 Apr 2008 20:37:31 +0300
Subject: [PATCH] IB/ipoib: fix net queue lockup
Fix the lockup of the net queue introduced in the split CQ patch.
The idea is to arm the send CQ just before posting the last send
request to the QP. When the completion handler is called, drain
the CQ. Since not all the CQEs might already be in the CQ, verify
that the the net queue has been woken up. If not arm a timer and
drain again at the timer function.
In order to reduce the number of cases the queue is stopped we should
use a larger tx queue.
Roland,
we haves seen a few other cases where a large tx queue is needed. I
think we should choose a larger default value than the current 64.
How about 256?
---
drivers/infiniband/ulp/ipoib/ipoib.h | 2 +
drivers/infiniband/ulp/ipoib/ipoib_ib.c | 47 +++++++++++++++++++++++++---
drivers/infiniband/ulp/ipoib/ipoib_verbs.c | 3 +-
3 files changed, 46 insertions(+), 6 deletions(-)
diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 9044f88..b46baf2 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -334,6 +334,7 @@ struct ipoib_dev_priv {
#endif
int hca_caps;
struct ipoib_ethtool_st ethtool;
+ struct timer_list poll_timer;
};
struct ipoib_ah {
@@ -404,6 +405,7 @@ extern struct workqueue_struct *ipoib_workqueue;
int ipoib_poll(struct napi_struct *napi, int budget);
void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr);
+void send_comp_handler(struct ib_cq *cq, void *dev_ptr);
struct ipoib_ah *ipoib_create_ah(struct net_device *dev,
struct ib_pd *pd, struct ib_ah_attr *attr);
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 97b815c..e620a90 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -461,6 +461,26 @@ void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr)
netif_rx_schedule(dev, &priv->napi);
}
+static void drain_tx_cq(struct net_device *dev)
+{
+ struct ipoib_dev_priv *priv = netdev_priv(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->tx_lock, flags);
+ while(poll_tx(priv))
+ ; /* nothing */
+
+ if (netif_queue_stopped(dev))
+ mod_timer(&priv->poll_timer, jiffies + 1);
+
+ spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
+void send_comp_handler(struct ib_cq *cq, void *dev_ptr)
+{
+ drain_tx_cq((struct net_device *)dev_ptr);
+}
+
static inline int post_send(struct ipoib_dev_priv *priv,
unsigned int wr_id,
struct ib_ah *address, u32 qpn,
@@ -555,12 +575,22 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb,
else
priv->tx_wr.send_flags &= ~IB_SEND_IP_CSUM;
+ if (++priv->tx_outstanding == ipoib_sendq_size) {
+ ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
+ if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
+ ipoib_warn(priv, "request notify on send queue failed\n");
+ netif_stop_queue(dev);
+ }
+
if (unlikely(post_send(priv, priv->tx_head & (ipoib_sendq_size - 1),
address->ah, qpn, tx_req, phead, hlen))) {
ipoib_warn(priv, "post_send failed\n");
++dev->stats.tx_errors;
+ --priv->tx_outstanding;
ipoib_dma_unmap_tx(priv->ca, tx_req);
dev_kfree_skb_any(skb);
+ if (netif_queue_stopped(dev))
+ netif_wake_queue(dev);
} else {
dev->trans_start = jiffies;
@@ -568,14 +598,11 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb,
++priv->tx_head;
skb_orphan(skb);
- if (++priv->tx_outstanding == ipoib_sendq_size) {
- ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
- netif_stop_queue(dev);
- }
}
if (unlikely(priv->tx_outstanding > MAX_SEND_CQE))
- poll_tx(priv);
+ while(poll_tx(priv))
+ ; /* nothing */
}
static void __ipoib_reap_ah(struct net_device *dev)
@@ -609,6 +636,11 @@ void ipoib_reap_ah(struct work_struct *work)
round_jiffies_relative(HZ));
}
+static void ipoib_ib_tx_timer_func(unsigned long ctx)
+{
+ drain_tx_cq((struct net_device *)ctx);
+}
+
int ipoib_ib_dev_open(struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -645,6 +677,10 @@ int ipoib_ib_dev_open(struct net_device *dev)
queue_delayed_work(ipoib_workqueue, &priv->ah_reap_task,
round_jiffies_relative(HZ));
+ init_timer(&priv->poll_timer);
+ priv->poll_timer.function = ipoib_ib_tx_timer_func;
+ priv->poll_timer.data = (unsigned long)dev;
+
set_bit(IPOIB_FLAG_INITIALIZED, &priv->flags);
return 0;
@@ -810,6 +846,7 @@ int ipoib_ib_dev_stop(struct net_device *dev, int flush)
ipoib_dbg(priv, "All sends and receives done.\n");
timeout:
+ del_timer_sync(&priv->poll_timer);
qp_attr.qp_state = IB_QPS_RESET;
if (ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE))
ipoib_warn(priv, "Failed to modify QP to RESET state\n");
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index c1e7ece..706384d 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -187,7 +187,8 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
goto out_free_mr;
}
- priv->send_cq = ib_create_cq(priv->ca, NULL, NULL, dev, ipoib_sendq_size, 0);
+ priv->send_cq = ib_create_cq(priv->ca, send_comp_handler, NULL, dev,
+ ipoib_sendq_size, 0);
if (IS_ERR(priv->send_cq)) {
printk(KERN_WARNING "%s: failed to create send CQ\n", ca->name);
goto out_free_recv_cq;
--
1.5.5
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