IPoIB: Double default RX/TX ring sizes

Increase IPoIB ring sizes to twice their original sizes (RX: 128->256,
TX: 64->128) to act as a shock absorber for high traffic peaks.  With
the current settings, we have seen cases that there are many calls to
netif_stop_queue(), which causes degradation in throughput.  Also,
larger receive buffer sizes help IPoIB in CM mode to avoid experiencing
RNR NAK conditions due to insufficient receive buffers at the SRQ.
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/ipoib/ipoib.h

@@ -70,8 +70,8 @@ enum {
 	IPOIB_CM_BUF_SIZE	  = IPOIB_CM_MTU  + IPOIB_ENCAP_LEN,
 	IPOIB_CM_HEAD_SIZE	  = IPOIB_CM_BUF_SIZE % PAGE_SIZE,
 	IPOIB_CM_RX_SG		  = ALIGN(IPOIB_CM_BUF_SIZE, PAGE_SIZE) / PAGE_SIZE,
-	IPOIB_RX_RING_SIZE	  = 128,
-	IPOIB_TX_RING_SIZE	  = 64,
+	IPOIB_RX_RING_SIZE	  = 256,
+	IPOIB_TX_RING_SIZE	  = 128,
 	IPOIB_MAX_QUEUE_SIZE	  = 8192,
 	IPOIB_MIN_QUEUE_SIZE	  = 2,
 	IPOIB_CM_MAX_CONN_QP	  = 4096,