Index: head/sys/dev/ena/ena.h
===================================================================
--- head/sys/dev/ena/ena.h
+++ head/sys/dev/ena/ena.h
@@ -41,7 +41,7 @@
 
 #define DRV_MODULE_VER_MAJOR	2
 #define DRV_MODULE_VER_MINOR	1
-#define DRV_MODULE_VER_SUBMINOR 1
+#define DRV_MODULE_VER_SUBMINOR 2
 
 #define DRV_MODULE_NAME		"ena"
 
@@ -307,8 +307,13 @@
 
 	/* Determines if device will use LLQ or normal mode for TX */
 	enum ena_admin_placement_policy_type tx_mem_queue_type;
-	/* The maximum length the driver can push to the device (For LLQ) */
-	uint8_t tx_max_header_size;
+	union {
+		/* The maximum length the driver can push to the device (For LLQ) */
+		uint8_t tx_max_header_size;
+		/* The maximum (and default) mbuf size for the Rx descriptor. */
+		uint16_t rx_mbuf_sz;
+
+	};
 
 	bool first_interrupt;
 	uint16_t no_interrupt_event_cnt;
Index: head/sys/dev/ena/ena.c
===================================================================
--- head/sys/dev/ena/ena.c
+++ head/sys/dev/ena/ena.c
@@ -368,6 +368,7 @@
 	ring->ena_dev = adapter->ena_dev;
 	ring->first_interrupt = false;
 	ring->no_interrupt_event_cnt = 0;
+	ring->rx_mbuf_sz = ena_mbuf_sz;
 }
 
 static void
@@ -508,9 +509,9 @@
 	    ENA_DMA_BIT_MASK(adapter->dma_width), /* lowaddr of excl window  */
 	    BUS_SPACE_MAXADDR, 			  /* highaddr of excl window */
 	    NULL, NULL,				  /* filter, filterarg 	     */
-	    MJUM16BYTES,			  /* maxsize 		     */
+	    ena_mbuf_sz,			  /* maxsize 		     */
 	    adapter->max_rx_sgl_size,		  /* nsegments 		     */
-	    MJUM16BYTES,			  /* maxsegsize 	     */
+	    ena_mbuf_sz,			  /* maxsegsize 	     */
 	    0,					  /* flags 		     */
 	    NULL,				  /* lockfunc 		     */
 	    NULL,				  /* lockarg 		     */
@@ -963,7 +964,8 @@
 		return (0);
 
 	/* Get mbuf using UMA allocator */
-	rx_info->mbuf = m_getjcl(M_NOWAIT, MT_DATA, M_PKTHDR, MJUM16BYTES);
+	rx_info->mbuf = m_getjcl(M_NOWAIT, MT_DATA, M_PKTHDR,
+	    rx_ring->rx_mbuf_sz);
 
 	if (unlikely(rx_info->mbuf == NULL)) {
 		counter_u64_add(rx_ring->rx_stats.mjum_alloc_fail, 1);
@@ -974,7 +976,7 @@
 		}
 		mlen = MCLBYTES;
 	} else {
-		mlen = MJUM16BYTES;
+		mlen = rx_ring->rx_mbuf_sz;
 	}
 	/* Set mbuf length*/
 	rx_info->mbuf->m_pkthdr.len = rx_info->mbuf->m_len = mlen;
Index: head/sys/dev/ena/ena_sysctl.h
===================================================================
--- head/sys/dev/ena/ena_sysctl.h
+++ head/sys/dev/ena/ena_sysctl.h
@@ -41,4 +41,7 @@
 
 void	ena_sysctl_add_nodes(struct ena_adapter *);
 
+extern int ena_enable_9k_mbufs;
+#define ena_mbuf_sz (ena_enable_9k_mbufs ? MJUM9BYTES : MJUMPAGESIZE)
+
 #endif /* !(ENA_SYSCTL_H) */
Index: head/sys/dev/ena/ena_sysctl.c
===================================================================
--- head/sys/dev/ena/ena_sysctl.c
+++ head/sys/dev/ena/ena_sysctl.c
@@ -48,6 +48,17 @@
 SYSCTL_INT(_hw_ena, OID_AUTO, log_level, CTLFLAG_RWTUN,
     &ena_log_level, 0, "Logging level indicating verbosity of the logs");
 
+/*
+ * Use 9k mbufs for the Rx buffers. Default to 0 (use page size mbufs instead).
+ * Using 9k mbufs in low memory conditions might cause allocation to take a lot
+ * of time and lead to the OS instability as it needs to look for the contiguous
+ * pages.
+ * However, page size mbufs has a bit smaller throughput than 9k mbufs, so if
+ * the network performance is the priority, the 9k mbufs can be used.
+ */
+int ena_enable_9k_mbufs = 0;
+SYSCTL_INT(_hw_ena, OID_AUTO, enable_9k_mbufs, CTLFLAG_RDTUN,
+    &ena_enable_9k_mbufs, 0, "Use 9 kB mbufs for Rx descriptors");
 
 void
 ena_sysctl_add_nodes(struct ena_adapter *adapter)