net/memif: optimize with one-way barrier

[dpdk.git] / doc / guides / prog_guide / kernel_nic_interface.rst

diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst b/doc/guides/prog_guide/kernel_nic_interface.rst
index 7fcbd93..2fd58e1 100644 (file)
--- a/doc/guides/prog_guide/kernel_nic_interface.rst
+++ b/doc/guides/prog_guide/kernel_nic_interface.rst
@@ -227,7 +227,7 @@ application functions:
 
 ``config_promiscusity``:
 
-    Called when the user changes the promiscusity state of the KNI
+    Called when the user changes the promiscuity state of the KNI
     interface.  For example, when the user runs ``ip link set promisc
     [on|off] dev <ifaceX>``. If the user sets this callback function to
     NULL, but sets the ``port_id`` field to a value other than -1, a default
@@ -235,6 +235,15 @@ application functions:
     will be called which calls ``rte_eth_promiscuous_<enable|disable>()``
     on the specified ``port_id``.
 
+``config_allmulticast``:
+
+    Called when the user changes the allmulticast state of the KNI interface.
+    For example, when the user runs ``ifconfig <ifaceX> [-]allmulti``. If the
+    user sets this callback function to NULL, but sets the ``port_id`` field to
+    a value other than -1, a default callback handler in the rte_kni library
+    ``kni_config_allmulticast()`` will be called which calls
+    ``rte_eth_allmulticast_<enable|disable>()`` on the specified ``port_id``.
+
 In order to run these callbacks, the application must periodically call
 the ``rte_kni_handle_request()`` function.  Any user callback function
 registered will be called directly from ``rte_kni_handle_request()`` so
@@ -268,12 +277,16 @@ Use Case: Ingress
 -----------------
 
 On the DPDK RX side, the mbuf is allocated by the PMD in the RX thread context.
-This thread will enqueue the mbuf in the rx_q FIFO.
+This thread will enqueue the mbuf in the rx_q FIFO,
+and the next pointers in mbuf-chain will convert to physical address.
 The KNI thread will poll all KNI active devices for the rx_q.
 If an mbuf is dequeued, it will be converted to a sk_buff and sent to the net stack via netif_rx().
-The dequeued mbuf must be freed, so the same pointer is sent back in the free_q FIFO.
+The dequeued mbuf must be freed, so the same pointer is sent back in the free_q FIFO,
+and next pointers must convert back to virtual address if exists before put in the free_q FIFO.
 
 The RX thread, in the same main loop, polls this FIFO and frees the mbuf after dequeuing it.
+The address conversion of the next pointer is to prevent the chained mbuf
+in different hugepage segments from causing kernel crash.
 
 Use Case: Egress
 ----------------
@@ -290,7 +303,8 @@ It then puts the mbuf back in the cache.
 Ethtool
 -------
 
-Ethtool is a Linux-specific tool with corresponding support in the kernel
-where each net device must register its own callbacks for the supported operations.
-The current implementation uses the igb/ixgbe modified Linux drivers for ethtool support.
-Ethtool is not supported in i40e and VMs (VF or EM devices).
+Ethtool is a Linux-specific tool with corresponding support in the kernel.
+The current version of kni provides minimal ethtool functionality
+including querying version and link state. It does not support link
+control, statistics, or dumping device registers.
+