doc: replace hugepages commands with dedicated tool

[dpdk.git] / doc / guides / nics / af_xdp.rst

diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index be268fe..5ed2437 100644 (file)
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -50,6 +50,7 @@ This is a Linux-specific PMD, thus the following prerequisites apply:
 *  For PMD zero copy, it requires kernel version later than v5.4-rc1;
 *  For shared_umem, it requires kernel version v5.10 or later and libbpf version
    v0.2.0 or later.
+*  For 32-bit OS, a kernel with version 5.4 or later is required.
 
 Set up an af_xdp interface
 -----------------------------
@@ -82,3 +83,28 @@ Limitations
 
   Note: The AF_XDP PMD will fail to initialise if an MTU which violates the driver's
   conditions as above is set prior to launching the application.
+
+- **Shared UMEM**
+
+  The sharing of UMEM is only supported for AF_XDP sockets with unique contexts.
+  The context refers to the netdev,qid tuple.
+
+  The following combination will fail:
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f1,shared_umem=1 \
+
+  Either of the following however is permitted since either the netdev or qid differs
+  between the two vdevs:
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f1,start_queue=1,shared_umem=1 \
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f2,shared_umem=1 \
\ No newline at end of file