[master] a4747b3 Add a parameter to tune the backend connection idle timeout.

[Poul-Henning Kamp]

commit a4747b3e39a53bdc250f1a404c410ad534510fa3
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Tue Jun 23 11:16:03 2015 +0000

    Add a parameter to tune the backend connection idle timeout.

diff --git a/bin/varnishd/cache/cache_backend_tcp.c b/bin/varnishd/cache/cache_backend_tcp.c
index c9d57d1..75f216d 100644
--- a/bin/varnishd/cache/cache_backend_tcp.c
+++ b/bin/varnishd/cache/cache_backend_tcp.c
@@ -60,7 +60,6 @@ struct tcp_pool {
 	struct lock		mtx;
 
 	struct waitfor		waitfor;
-	volatile double		timeout;
 
 	VTAILQ_HEAD(, vbc)	connlist;
 	int			n_conn;
@@ -165,10 +164,9 @@ VBT_Ref(const struct suckaddr *ip4, const struct suckaddr *ip6)
 	VTAILQ_INIT(&tp->connlist);
 	VTAILQ_INIT(&tp->killlist);
 	VTAILQ_INSERT_HEAD(&pools, tp, list);
-	tp->timeout = 60;
 	INIT_OBJ(&tp->waitfor, WAITFOR_MAGIC);
 	tp->waitfor.func = tcp_handle;
-	tp->waitfor.tmo = &tp->timeout;
+	tp->waitfor.tmo = &cache_param->backend_idle_timeout;
 	return (tp);
 }
 
diff --git a/bin/varnishd/cache/cache_vcl.c b/bin/varnishd/cache/cache_vcl.c
index 40b630a..6df2a2f 100644
--- a/bin/varnishd/cache/cache_vcl.c
+++ b/bin/varnishd/cache/cache_vcl.c
@@ -330,7 +330,7 @@ VCL_Name(const struct vcl *vcl)
 const struct vrt_backend_probe *
 VCL_DefaultProbe(const struct vcl *vcl)
 {
-	
+
 	CHECK_OBJ_NOTNULL(vcl, VCL_MAGIC);
 	return (vcl->conf->default_probe);
 }
diff --git a/include/tbl/params.h b/include/tbl/params.h
index 1581374..22addb0 100644
--- a/include/tbl/params.h
+++ b/include/tbl/params.h
@@ -195,6 +195,20 @@ PARAM(
 	/* func */	NULL
 )
 
+PARAM(
+	/* name */	backend_idle_timeout,
+	/* tweak */	timeout,
+	/* min */	"1",
+	/* max */	NULL,
+	/* default */	"60",
+	/* units */	"seconds",
+	/* flags */	0,
+	/* s-text */
+	"Timeout before we close unused backend connections.",
+	/* l-text */	"",
+	/* func */	NULL
+)
+
 /**********************************************************************/
 #if 0 /* NOT YET */