cns3xxx: reduce buffer allocation size to 2048 bytes, improves ethernet performance

SVN-Revision: 35917

target/linux/cns3xxx/files/drivers/net/ethernet/cavium/cns3xxx_eth.c

@@ -38,7 +38,7 @@
 #define RX_BUFFER_ALIGN_MASK (~(RX_BUFFER_ALIGN - 1))
 
 #define SKB_HEAD_ALIGN (((PAGE_SIZE - NET_SKB_PAD) % RX_BUFFER_ALIGN) + NET_SKB_PAD + NET_IP_ALIGN)
-#define RX_SEGMENT_ALLOC_SIZE 4096
+#define RX_SEGMENT_ALLOC_SIZE 2048
 #define RX_SEGMENT_BUFSIZE (SKB_WITH_OVERHEAD(RX_SEGMENT_ALLOC_SIZE))
 #define RX_SEGMENT_MRU (((RX_SEGMENT_BUFSIZE - SKB_HEAD_ALIGN) & RX_BUFFER_ALIGN_MASK) - NET_IP_ALIGN)
 #define MAX_MTU	9500