bool separate_tx_rx_irq = 1;
module_param(separate_tx_rx_irq, bool, 0644);
-/* When guest ring is filled up, qdisc queues the packets for us, but we have
- * to timeout them, otherwise other guests' packets can get stuck there
+/* The time that packets can stay on the guest Rx internal queue
+ * before they are dropped.
*/
unsigned int rx_drain_timeout_msecs = 10000;
module_param(rx_drain_timeout_msecs, uint, 0444);
unsigned int rx_drain_timeout_jiffies;
+/* The length of time before the frontend is considered unresponsive
+ * because it isn't providing Rx slots.
+ */
+static unsigned int rx_stall_timeout_msecs = 60000;
+module_param(rx_stall_timeout_msecs, uint, 0444);
+static unsigned int rx_stall_timeout_jiffies;
+
unsigned int xenvif_max_queues;
module_param_named(max_queues, xenvif_max_queues, uint, 0644);
MODULE_PARM_DESC(max_queues,
s8 st);
static inline int tx_work_todo(struct xenvif_queue *queue);
-static inline int rx_work_todo(struct xenvif_queue *queue);
static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
u16 id,
return false;
}
+void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->rx_queue.lock, flags);
+
+ __skb_queue_tail(&queue->rx_queue, skb);
+
+ queue->rx_queue_len += skb->len;
+ if (queue->rx_queue_len > queue->rx_queue_max)
+ netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
+
+ spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+}
+
+static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
+{
+ struct sk_buff *skb;
+
+ spin_lock_irq(&queue->rx_queue.lock);
+
+ skb = __skb_dequeue(&queue->rx_queue);
+ if (skb)
+ queue->rx_queue_len -= skb->len;
+
+ spin_unlock_irq(&queue->rx_queue.lock);
+
+ return skb;
+}
+
+static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
+{
+ spin_lock_irq(&queue->rx_queue.lock);
+
+ if (queue->rx_queue_len < queue->rx_queue_max)
+ netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
+
+ spin_unlock_irq(&queue->rx_queue.lock);
+}
+
+
+static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
+{
+ struct sk_buff *skb;
+ while ((skb = xenvif_rx_dequeue(queue)) != NULL)
+ kfree_skb(skb);
+}
+
+static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
+{
+ struct sk_buff *skb;
+
+ for(;;) {
+ skb = skb_peek(&queue->rx_queue);
+ if (!skb)
+ break;
+ if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
+ break;
+ xenvif_rx_dequeue(queue);
+ kfree_skb(skb);
+ }
+}
+
/*
* Returns true if we should start a new receive buffer instead of
* adding 'size' bytes to a buffer which currently contains 'offset'
return meta;
}
-struct xenvif_rx_cb {
- int meta_slots_used;
- bool full_coalesce;
-};
-
-#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
-
/*
* Set up the grant operations for this fragment. If it's a flipping
* interface, we also set up the unmap request from here.
skb_queue_head_init(&rxq);
- while ((skb = skb_dequeue(&queue->rx_queue)) != NULL) {
+ while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)
+ && (skb = xenvif_rx_dequeue(queue)) != NULL) {
RING_IDX max_slots_needed;
RING_IDX old_req_cons;
RING_IDX ring_slots_used;
int i;
+ queue->last_rx_time = jiffies;
+
/* We need a cheap worse case estimate for the number of
* slots we'll use.
*/
skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
max_slots_needed++;
- /* If the skb may not fit then bail out now */
- if (!xenvif_rx_ring_slots_available(queue, max_slots_needed)) {
- skb_queue_head(&queue->rx_queue, skb);
- need_to_notify = true;
- queue->rx_last_skb_slots = max_slots_needed;
- break;
- } else
- queue->rx_last_skb_slots = 0;
-
old_req_cons = queue->rx.req_cons;
XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
ring_slots_used = queue->rx.req_cons - old_req_cons;
}
}
-static inline int rx_work_todo(struct xenvif_queue *queue)
-{
- return (!skb_queue_empty(&queue->rx_queue) &&
- xenvif_rx_ring_slots_available(queue, queue->rx_last_skb_slots));
-}
-
static inline int tx_work_todo(struct xenvif_queue *queue)
{
if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
return err;
}
-static void xenvif_start_queue(struct xenvif_queue *queue)
+static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
{
- if (xenvif_schedulable(queue->vif))
- xenvif_wake_queue(queue);
+ struct xenvif *vif = queue->vif;
+
+ queue->stalled = true;
+
+ /* At least one queue has stalled? Disable the carrier. */
+ spin_lock(&vif->lock);
+ if (vif->stalled_queues++ == 0) {
+ netdev_info(vif->dev, "Guest Rx stalled");
+ netif_carrier_off(vif->dev);
+ }
+ spin_unlock(&vif->lock);
}
-/* Only called from the queue's thread, it handles the situation when the guest
- * doesn't post enough requests on the receiving ring.
- * First xenvif_start_xmit disables QDisc and start a timer, and then either the
- * timer fires, or the guest send an interrupt after posting new request. If it
- * is the timer, the carrier is turned off here.
- * */
-static void xenvif_rx_purge_event(struct xenvif_queue *queue)
+static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
{
- /* Either the last unsuccesful skb or at least 1 slot should fit */
- int needed = queue->rx_last_skb_slots ?
- queue->rx_last_skb_slots : 1;
+ struct xenvif *vif = queue->vif;
- /* It is assumed that if the guest post new slots after this, the RX
- * interrupt will set the QUEUE_STATUS_RX_PURGE_EVENT bit and wake up
- * the thread again
- */
- set_bit(QUEUE_STATUS_RX_STALLED, &queue->status);
- if (!xenvif_rx_ring_slots_available(queue, needed)) {
- rtnl_lock();
- if (netif_carrier_ok(queue->vif->dev)) {
- /* Timer fired and there are still no slots. Turn off
- * everything except the interrupts
- */
- netif_carrier_off(queue->vif->dev);
- skb_queue_purge(&queue->rx_queue);
- queue->rx_last_skb_slots = 0;
- if (net_ratelimit())
- netdev_err(queue->vif->dev, "Carrier off due to lack of guest response on queue %d\n", queue->id);
- } else {
- /* Probably an another queue already turned the carrier
- * off, make sure nothing is stucked in the internal
- * queue of this queue
- */
- skb_queue_purge(&queue->rx_queue);
- queue->rx_last_skb_slots = 0;
- }
- rtnl_unlock();
- } else if (!netif_carrier_ok(queue->vif->dev)) {
- unsigned int num_queues = queue->vif->num_queues;
- unsigned int i;
- /* The carrier was down, but an interrupt kicked
- * the thread again after new requests were
- * posted
- */
- clear_bit(QUEUE_STATUS_RX_STALLED,
- &queue->status);
- rtnl_lock();
- netif_carrier_on(queue->vif->dev);
- netif_tx_wake_all_queues(queue->vif->dev);
- rtnl_unlock();
+ queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
+ queue->stalled = false;
- for (i = 0; i < num_queues; i++) {
- struct xenvif_queue *temp = &queue->vif->queues[i];
+ /* All queues are ready? Enable the carrier. */
+ spin_lock(&vif->lock);
+ if (--vif->stalled_queues == 0) {
+ netdev_info(vif->dev, "Guest Rx ready");
+ netif_carrier_on(vif->dev);
+ }
+ spin_unlock(&vif->lock);
+}
- xenvif_napi_schedule_or_enable_events(temp);
- }
- if (net_ratelimit())
- netdev_err(queue->vif->dev, "Carrier on again\n");
- } else {
- /* Queuing were stopped, but the guest posted
- * new requests and sent an interrupt
- */
- clear_bit(QUEUE_STATUS_RX_STALLED,
- &queue->status);
- del_timer_sync(&queue->rx_stalled);
- xenvif_start_queue(queue);
+static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+
+ prod = queue->rx.sring->req_prod;
+ cons = queue->rx.req_cons;
+
+ return !queue->stalled
+ && prod - cons < XEN_NETBK_RX_SLOTS_MAX
+ && time_after(jiffies,
+ queue->last_rx_time + rx_stall_timeout_jiffies);
+}
+
+static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+
+ prod = queue->rx.sring->req_prod;
+ cons = queue->rx.req_cons;
+
+ return queue->stalled
+ && prod - cons >= XEN_NETBK_RX_SLOTS_MAX;
+}
+
+static bool xenvif_have_rx_work(struct xenvif_queue *queue)
+{
+ return (!skb_queue_empty(&queue->rx_queue)
+ && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
+ || xenvif_rx_queue_stalled(queue)
+ || xenvif_rx_queue_ready(queue)
+ || kthread_should_stop()
+ || queue->vif->disabled;
+}
+
+static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
+{
+ struct sk_buff *skb;
+ long timeout;
+
+ skb = skb_peek(&queue->rx_queue);
+ if (!skb)
+ return MAX_SCHEDULE_TIMEOUT;
+
+ timeout = XENVIF_RX_CB(skb)->expires - jiffies;
+ return timeout < 0 ? 0 : timeout;
+}
+
+/* Wait until the guest Rx thread has work.
+ *
+ * The timeout needs to be adjusted based on the current head of the
+ * queue (and not just the head at the beginning). In particular, if
+ * the queue is initially empty an infinite timeout is used and this
+ * needs to be reduced when a skb is queued.
+ *
+ * This cannot be done with wait_event_timeout() because it only
+ * calculates the timeout once.
+ */
+static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
+{
+ DEFINE_WAIT(wait);
+
+ if (xenvif_have_rx_work(queue))
+ return;
+
+ for (;;) {
+ long ret;
+
+ prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
+ if (xenvif_have_rx_work(queue))
+ break;
+ ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
+ if (!ret)
+ break;
}
+ finish_wait(&queue->wq, &wait);
}
int xenvif_kthread_guest_rx(void *data)
{
struct xenvif_queue *queue = data;
- struct sk_buff *skb;
+ struct xenvif *vif = queue->vif;
- while (!kthread_should_stop()) {
- wait_event_interruptible(queue->wq,
- rx_work_todo(queue) ||
- queue->vif->disabled ||
- test_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status) ||
- kthread_should_stop());
+ for (;;) {
+ xenvif_wait_for_rx_work(queue);
if (kthread_should_stop())
break;
* context so we defer it here, if this thread is
* associated with queue 0.
*/
- if (unlikely(queue->vif->disabled && queue->id == 0)) {
- xenvif_carrier_off(queue->vif);
- } else if (unlikely(queue->vif->disabled)) {
- /* kthread_stop() would be called upon this thread soon,
- * be a bit proactive
- */
- skb_queue_purge(&queue->rx_queue);
- queue->rx_last_skb_slots = 0;
- } else if (unlikely(test_and_clear_bit(QUEUE_STATUS_RX_PURGE_EVENT,
- &queue->status))) {
- xenvif_rx_purge_event(queue);
- } else if (!netif_carrier_ok(queue->vif->dev)) {
- /* Another queue stalled and turned the carrier off, so
- * purge the internal queue of queues which were not
- * blocked
- */
- skb_queue_purge(&queue->rx_queue);
- queue->rx_last_skb_slots = 0;
+ if (unlikely(vif->disabled && queue->id == 0)) {
+ xenvif_carrier_off(vif);
+ xenvif_rx_queue_purge(queue);
+ continue;
}
if (!skb_queue_empty(&queue->rx_queue))
xenvif_rx_action(queue);
+ /* If the guest hasn't provided any Rx slots for a
+ * while it's probably not responsive, drop the
+ * carrier so packets are dropped earlier.
+ */
+ if (xenvif_rx_queue_stalled(queue))
+ xenvif_queue_carrier_off(queue);
+ else if (xenvif_rx_queue_ready(queue))
+ xenvif_queue_carrier_on(queue);
+
+ /* Queued packets may have foreign pages from other
+ * domains. These cannot be queued indefinitely as
+ * this would starve guests of grant refs and transmit
+ * slots.
+ */
+ xenvif_rx_queue_drop_expired(queue);
+
+ xenvif_rx_queue_maybe_wake(queue);
+
cond_resched();
}
/* Bin any remaining skbs */
- while ((skb = skb_dequeue(&queue->rx_queue)) != NULL)
- dev_kfree_skb(skb);
+ xenvif_rx_queue_purge(queue);
return 0;
}
goto failed_init;
rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
+ rx_stall_timeout_jiffies = msecs_to_jiffies(rx_stall_timeout_msecs);
#ifdef CONFIG_DEBUG_FS
xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
projects / firefly-linux-kernel-4.4.55.git / blobdiff