net: mvpp2: limit TSO segments and use stop/wake thresholds
Too many TSO descriptors can be required for the default queue size,
when using small MSS values for example. Prevent this by adding a
maximum number of allowed TSO segments (300). In addition set a stop and
a wake thresholds to stop the queue when there's no room for a 1 "worst
case scenario skb". Wake up the queue when the number of descriptors is
low enough.
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c
index 54d80df..340b4d6 100644
--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -493,6 +493,13 @@
/* Maximum number of TXQs used by single port */
#define MVPP2_MAX_TXQ 8
+/* MVPP2_MAX_TSO_SEGS is the maximum number of fragments to allow in the GSO
+ * skb. As we need a maxium of two descriptors per fragments (1 header, 1 data),
+ * multiply this value by two to count the maximum number of skb descs needed.
+ */
+#define MVPP2_MAX_TSO_SEGS 300
+#define MVPP2_MAX_SKB_DESCS (MVPP2_MAX_TSO_SEGS * 2 + MAX_SKB_FRAGS)
+
/* Dfault number of RXQs in use */
#define MVPP2_DEFAULT_RXQ 4
@@ -1045,6 +1052,9 @@
*/
int count;
+ int wake_threshold;
+ int stop_threshold;
+
/* Number of Tx DMA descriptors reserved for each CPU */
int reserved_num;
@@ -5393,7 +5403,7 @@
txq_pcpu->count -= tx_done;
if (netif_tx_queue_stopped(nq))
- if (txq_pcpu->size - txq_pcpu->count >= MAX_SKB_FRAGS + 1)
+ if (txq_pcpu->count <= txq_pcpu->wake_threshold)
netif_tx_wake_queue(nq);
}
@@ -5636,6 +5646,9 @@
txq_pcpu->txq_put_index = 0;
txq_pcpu->txq_get_index = 0;
+ txq_pcpu->stop_threshold = txq->size - MVPP2_MAX_SKB_DESCS;
+ txq_pcpu->wake_threshold = txq_pcpu->stop_threshold / 2;
+
txq_pcpu->tso_headers =
dma_alloc_coherent(port->dev->dev.parent,
txq_pcpu->size * TSO_HEADER_SIZE,
@@ -6508,7 +6521,7 @@
wmb();
mvpp2_aggr_txq_pend_desc_add(port, frags);
- if (txq_pcpu->size - txq_pcpu->count < MAX_SKB_FRAGS + 1)
+ if (txq_pcpu->count >= txq_pcpu->stop_threshold)
netif_tx_stop_queue(nq);
u64_stats_update_begin(&stats->syncp);
@@ -7732,6 +7745,7 @@
dev->features = features | NETIF_F_RXCSUM;
dev->hw_features |= features | NETIF_F_RXCSUM | NETIF_F_GRO;
dev->vlan_features |= features;
+ dev->gso_max_segs = MVPP2_MAX_TSO_SEGS;
/* MTU range: 68 - 9676 */
dev->min_mtu = ETH_MIN_MTU;