From 8b64fa1e120d0c6c1935ac745c5beb3132259131 Mon Sep 17 00:00:00 2001
From: Bryan Drewery <bdrewery@FreeBSD.org>
Date: Wed, 26 Aug 2015 03:37:18 +0000
Subject: [PATCH] Avoid taking proctree_lock and searching parents in wrappers
 if not needed.

This should help the case where filemon is loaded but not in use.

Sponsored by:	EMC / Isilon Storage Division
MFC after:	2 weeks
---
 sys/dev/filemon/filemon_wrapper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/dev/filemon/filemon_wrapper.c b/sys/dev/filemon/filemon_wrapper.c
index e162cf58bb2..d107a40892f 100644
--- a/sys/dev/filemon/filemon_wrapper.c
+++ b/sys/dev/filemon/filemon_wrapper.c
@@ -88,6 +88,10 @@ filemon_pid_check(struct proc *p)
 	struct filemon *filemon;
 
 	filemon_lock_read();
+	if (TAILQ_EMPTY(&filemons_inuse)) {
+		filemon_unlock_read();
+		return (NULL);
+	}
 	sx_slock(&proctree_lock);
 	while (p != initproc) {
 		TAILQ_FOREACH(filemon, &filemons_inuse, link) {