#define XENVIF_QUEUE_LENGTH 32
#define XENVIF_NAPI_WEIGHT 64
+/* Number of bytes allowed on the internal guest Rx queue. */
+#define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
+
/* This function is used to set SKBTX_DEV_ZEROCOPY as well as
* increasing the inflight counter. We need to increase the inflight
* counter because core driver calls into xenvif_zerocopy_callback
int xenvif_schedulable(struct xenvif *vif)
{
return netif_running(vif->dev) &&
- test_bit(VIF_STATUS_CONNECTED, &vif->status);
+ test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
+ !vif->disabled;
}
static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
{
struct xenvif_queue *queue = dev_id;
- struct netdev_queue *net_queue =
- netdev_get_tx_queue(queue->vif->dev, queue->id);
- /* QUEUE_STATUS_RX_PURGE_EVENT is only set if either QDisc was off OR
- * the carrier went down and this queue was previously blocked
- */
- if (unlikely(netif_tx_queue_stopped(net_queue) ||
- (!netif_carrier_ok(queue->vif->dev) &&
- test_bit(QUEUE_STATUS_RX_STALLED, &queue->status))))
- set_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status);
xenvif_kick_thread(queue);
return IRQ_HANDLED;
netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
}
-/* Callback to wake the queue's thread and turn the carrier off on timeout */
-static void xenvif_rx_stalled(unsigned long data)
-{
- struct xenvif_queue *queue = (struct xenvif_queue *)data;
-
- if (xenvif_queue_stopped(queue)) {
- set_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status);
- xenvif_kick_thread(queue);
- }
-}
-
static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
u16 index;
- int min_slots_needed;
+ struct xenvif_rx_cb *cb;
BUG_ON(skb->dev != dev);
!xenvif_schedulable(vif))
goto drop;
- /* At best we'll need one slot for the header and one for each
- * frag.
- */
- min_slots_needed = 1 + skb_shinfo(skb)->nr_frags;
+ cb = XENVIF_RX_CB(skb);
+ cb->expires = jiffies + rx_drain_timeout_jiffies;
- /* If the skb is GSO then we'll also need an extra slot for the
- * metadata.
- */
- if (skb_is_gso(skb))
- min_slots_needed++;
-
- /* If the skb can't possibly fit in the remaining slots
- * then turn off the queue to give the ring a chance to
- * drain.
- */
- if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) {
- queue->rx_stalled.function = xenvif_rx_stalled;
- queue->rx_stalled.data = (unsigned long)queue;
- netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
- mod_timer(&queue->rx_stalled,
- jiffies + rx_drain_timeout_jiffies);
- }
-
- skb_queue_tail(&queue->rx_queue, skb);
+ xenvif_rx_queue_tail(queue, skb);
xenvif_kick_thread(queue);
return NETDEV_TX_OK;
init_timer(&queue->credit_timeout);
queue->credit_window_start = get_jiffies_64();
+ queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
+
skb_queue_head_init(&queue->rx_queue);
skb_queue_head_init(&queue->tx_queue);
queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
}
- init_timer(&queue->rx_stalled);
-
return 0;
}
netif_napi_del(&queue->napi);
if (queue->task) {
- del_timer_sync(&queue->rx_stalled);
kthread_stop(queue->task);
queue->task = NULL;
}
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);
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;
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 bool xenvif_have_rx_work(struct xenvif_queue *queue)
{
- if (xenvif_schedulable(queue->vif))
- xenvif_wake_queue(queue);
+ return (!skb_queue_empty(&queue->rx_queue)
+ && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
+ || kthread_should_stop()
+ || queue->vif->disabled;
}
-/* 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 long xenvif_rx_queue_timeout(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 sk_buff *skb;
+ long timeout;
- /* 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();
+ skb = skb_peek(&queue->rx_queue);
+ if (!skb)
+ return MAX_SCHEDULE_TIMEOUT;
- for (i = 0; i < num_queues; i++) {
- struct xenvif_queue *temp = &queue->vif->queues[i];
+ timeout = XENVIF_RX_CB(skb)->expires - jiffies;
+ return timeout < 0 ? 0 : timeout;
+}
- 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);
+/* 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);
+ /* 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;
}
projects / users / willy / linux.git / commitdiff