vswitchd: Always configure a default queue for QoS.

When an interface has QoS configured but no default queue (queue 0), OVS
has until now installed that QoS configuration literally, which causes all
packets destined for this default queue to be dropped.  This behavior is
usually both unexpected and undesirable.

This commit changes behavior so that, when no default queue is configured,
OVS uses a default "empty" configuration for the default queue.  This
behavior should be more acceptable when QoS is slightly misconfigured.

I tested that, without this patch, configuring only queue 1 causes "tc
class show" to show only queue 1 (handle 1:2) for linux-htb and linux-hfsc,
and that with this patch it shows configurations for both queue 0 (handle
1:1) and queue 1.

Bug #5583.
Feature #7413.
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 6c6928a..aed36c6 100644 (file)
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2571,9 +2571,12 @@ iface_configure_qos(struct iface *iface, const struct ovsrec_qos *qos)
         if (!queue_zero) {
             static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
             VLOG_WARN_RL(&rl, "interface %s: QoS configured without a default "
-                         "queue (queue 0).  Packets not directed to a "
-                         "correctly configured queue may be dropped.",
+                         "queue (queue 0).  Using default configuration.",
                          iface->name);
+
+            shash_init(&details);
+            netdev_set_queue(iface->netdev, 0, &details);
+            shash_destroy(&details);
         }
     }
 

diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 0d2c6ba..4b1e137 100644 (file)
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -1541,6 +1541,16 @@
         OpenFlow in <code>struct ofp_action_enqueue</code> and other
         structures.  Queue 0 is used by OpenFlow output actions that do not
         specify a specific queue.</p>
+
+      <p>
+        Queue 0 is the ``default queue.''  It is used by OpenFlow output
+        actions when no specific queue has been set.  Ordinarily <ref
+        column="queues"/> should include a configuration for queue 0.  When no
+        configuration for queue 0 is present, a default configuration is used.
+        (Before version 1.6, Open vSwitch would leave queue 0 unconfigured in
+        this case.  With some queuing disciplines, this dropped all packets
+        destined for the default queue.)
+      </p>
     </column>
 
     <column name="other_config">