Add a VSL tag "Storage" which tells us which stevedore the object

went into.

bin/varnishd/storage/stevedore.c

@@ -296,6 +296,7 @@ STV_MkObject(struct stevedore *stv, struct busyobj *bo,
 	o->objcore->methods = &default_oc_methods;
 	o->objcore->priv = o;
 	o->objcore->priv2 = (uintptr_t)stv;
+	VSLb(bo->vsl, SLT_Storage, "%s %s", stv->name, stv->ident);
 	return (o);
 }
 

include/tbl/vsl_tags.h

@@ -451,4 +451,13 @@ SLTM(VSL, 0, "VSL API warnings and error message",
 	" reading the shared memory log.\n\n"
 )
 
+SLTM(Storage, 0, "Where object is stored",
+	"Type and name of stevedore object is stored in.\n\n"
+	"The format is::\n\n"
+	"\t%s %s\n"
+	"\t|  |\n"
+	"\t|  +- Name of stevedore\n"
+	"\t+---- Type (\"malloc\", \"file\", \"persistent\" etc.)\n"
+	"\n"
+)
 #undef NODEF_NOTICE