Index: sys/sys/sbuf.h
===================================================================
--- sys/sys/sbuf.h	(revision 262601)
+++ sys/sys/sbuf.h	(working copy)
@@ -41,6 +41,9 @@
  */
 struct sbuf {
 	char		*s_buf;		/* storage buffer */
+#define SBUF_SSO_LEN	64		/* sso storage buffer length */
+	char		 s_sso_buf[SBUF_SSO_LEN];
+					/* sso storage buffer */
 	sbuf_drain_func	*s_drain_func;	/* drain function */
 	void		*s_drain_arg;	/* user-supplied drain argument */
 	int		 s_error;	/* current error code */
Index: sys/kern/subr_sbuf.c
===================================================================
--- sys/kern/subr_sbuf.c	(revision 262601)
+++ sys/kern/subr_sbuf.c	(working copy)
@@ -157,6 +157,11 @@
 	if (!SBUF_CANEXTEND(s))
 		return (-1);
 	newsize = sbuf_extendsize(s->s_size + addlen);
+	if (s->s_buf == s->s_sso_buf && newsize <= SBUF_SSO_LEN) {
+		s->s_size = newsize;
+		return (0);
+	}
+
 	newbuf = SBMALLOC(newsize);
 	if (newbuf == NULL)
 		return (-1);
@@ -195,6 +200,11 @@
 	if ((flags & SBUF_AUTOEXTEND) != 0)
 		s->s_size = sbuf_extendsize(s->s_size);
 
+	if (s->s_size <= SBUF_SSO_LEN) {
+		s->s_buf = s->s_sso_buf;
+		return (s);
+	}
+
 	s->s_buf = SBMALLOC(s->s_size);
 	if (s->s_buf == NULL)
 		return (NULL);