Allow early drop for non-ALTQ enabled queues in an ALTQ-enabled kernel.

Previously the early drop was disabled unconditionally for ALTQ-enabled
kernels.

This should give some benefit for the normal gateway + LAN-server case with
a busy LAN leg and an ALTQ managed uplink.

Reviewed and style help from:	cperciva, pjd

1 files changed, 14 insertions, 13 deletions

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 7ed86b6..3576905 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -370,23 +370,24 @@ again:
 		}
 	}
 #endif /* notdef */
-#ifdef ALTQ
-	/*
-	 * disable packet drop hack.
-	 * packetdrop should be done by queueing.
-	 */
-#else /* !ALTQ */
 	/*
-	 * Verify that we have any chance at all of being able to queue
-	 *      the packet or packet fragments
+	 * Verify that we have any chance at all of being able to queue the
+	 * packet or packet fragments, unless ALTQ is enabled on the given
+	 * interface in which case packetdrop should be done by queueing.
 	 */
+#ifdef ALTQ
+	if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
+	    ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
+	    ifp->if_snd.ifq_maxlen))
+#else
 	if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
-		ifp->if_snd.ifq_maxlen) {
-			error = ENOBUFS;
-			ipstat.ips_odropped++;
-			goto bad;
+	    ifp->if_snd.ifq_maxlen)
+#endif /* ALTQ */
+	{
+		error = ENOBUFS;
+		ipstat.ips_odropped++;
+		goto bad;
 	}
-#endif /* !ALTQ */
 
 	/*
 	 * Look for broadcast address and