xen-netback: notify immediately after pushing Tx response.
This fixes a performance regression introduced by
7fbb9d8415d4a51cf542e87cf3a717a9f7e6aedc (xen-netback: release pending
index before pushing Tx responses)
Moving the notify outside of the spin locks means it can be delayed a
long time (if the dealloc thread is descheduled or there is an
interrupt or softirq).
Signed-off-by: David Vrabel <[email protected]>
Reviewed-by: Zoltan Kiss <[email protected]>
Acked-by: Wei Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index cab9f52..997cf09 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -96,6 +96,7 @@
static void make_tx_response(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp,
s8 st);
+static void push_tx_responses(struct xenvif_queue *queue);
static inline int tx_work_todo(struct xenvif_queue *queue);
@@ -655,15 +656,10 @@
unsigned long flags;
do {
- int notify;
-
spin_lock_irqsave(&queue->response_lock, flags);
make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
- RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
+ push_tx_responses(queue);
spin_unlock_irqrestore(&queue->response_lock, flags);
- if (notify)
- notify_remote_via_irq(queue->tx_irq);
-
if (cons == end)
break;
txp = RING_GET_REQUEST(&queue->tx, cons++);
@@ -1657,7 +1653,6 @@
{
struct pending_tx_info *pending_tx_info;
pending_ring_idx_t index;
- int notify;
unsigned long flags;
pending_tx_info = &queue->pending_tx_info[pending_idx];
@@ -1673,12 +1668,9 @@
index = pending_index(queue->pending_prod++);
queue->pending_ring[index] = pending_idx;
- RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
+ push_tx_responses(queue);
spin_unlock_irqrestore(&queue->response_lock, flags);
-
- if (notify)
- notify_remote_via_irq(queue->tx_irq);
}
@@ -1699,6 +1691,15 @@
queue->tx.rsp_prod_pvt = ++i;
}
+static void push_tx_responses(struct xenvif_queue *queue)
+{
+ int notify;
+
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
+ if (notify)
+ notify_remote_via_irq(queue->tx_irq);
+}
+
static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
u16 id,
s8 st,
