Index: uipc_mbuf.c
===================================================================
RCS file: /cvs/src/sys/kern/uipc_mbuf.c,v
retrieving revision 1.199
diff -u -p -r1.199 uipc_mbuf.c
--- uipc_mbuf.c	11 Dec 2014 19:21:57 -0000	1.199
+++ uipc_mbuf.c	28 Dec 2014 09:25:22 -0000
@@ -147,7 +147,6 @@ mbinit(void)
 	pool_init(&mbpool, MSIZE, 0, 0, 0, "mbufpl", NULL);
 	pool_setipl(&mbpool, IPL_NET);
 	pool_set_constraints(&mbpool, &kp_dma_contig);
-	pool_setlowat(&mbpool, mblowat);
 
 	pool_init(&mtagpool, PACKET_TAG_MAXSIZE + sizeof(struct m_tag),
 	    0, 0, 0, "mtagpl", NULL);
@@ -156,11 +155,10 @@ mbinit(void)
 	for (i = 0; i < nitems(mclsizes); i++) {
 		snprintf(mclnames[i], sizeof(mclnames[0]), "mcl%dk",
 		    mclsizes[i] >> 10);
-		pool_init(&mclpools[i], mclsizes[i], 0, 0, 0,
+		pool_init(&mclpools[i], mclsizes[i], 1024, 0, 0,
 		    mclnames[i], NULL);
 		pool_setipl(&mclpools[i], IPL_NET);
 		pool_set_constraints(&mclpools[i], &kp_dma_contig);
-		pool_setlowat(&mclpools[i], mcllowat);
 	}
 
 	nmbclust_update();
@@ -169,25 +167,7 @@ mbinit(void)
 void
 nmbclust_update(void)
 {
-	int i;
-	/*
-	 * Set the hard limit on the mclpools to the number of
-	 * mbuf clusters the kernel is to support.  Log the limit
-	 * reached message max once a minute.
-	 */
-	for (i = 0; i < nitems(mclsizes); i++) {
-		(void)pool_sethardlimit(&mclpools[i], nmbclust,
-		    mclpool_warnmsg, 60);
-		/*
-		 * XXX this needs to be reconsidered.
-		 * Setting the high water mark to nmbclust is too high
-		 * but we need to have enough spare buffers around so that
-		 * allocations in interrupt context don't fail or mclgeti()
-		 * drivers may end up with empty rings.
-		 */
-		pool_sethiwat(&mclpools[i], nmbclust);
-	}
-	pool_sethiwat(&mbpool, nmbclust);
+	(void)pool_sethardlimit(&mbpool, nmbclust, mclpool_warnmsg, 60);
 }
 
 /*
@@ -1356,14 +1336,24 @@ mq_dequeue(struct mbuf_queue *mq)
 int
 mq_enlist(struct mbuf_queue *mq, struct mbuf_list *ml)
 {
-	int full;
+	struct mbuf *m;
+	int dropped = 0;
 
 	mtx_enter(&mq->mq_mtx);
-	ml_join(&mq->mq_list, ml);
-	full = mq_len(mq) >= mq->mq_maxlen;
+	if (mq_len(mq) < mq->mq_maxlen)
+		ml_join(&mq->mq_list, ml);
+	else {
+		mq->mq_drops += ml_len(ml);
+		dropped = 1;
+	}
 	mtx_leave(&mq->mq_mtx);
 
-	return (full);
+	if (dropped) {
+		while ((m = ml_dequeue(ml)) != NULL)
+			m_freem(m);
+	}
+
+	return (dropped);
 }
 
 void