* Factor out the object system from new-bus so that it can be used by

  non-device code.
* Re-implement the method dispatch to improve efficiency. The new system
  takes about 40ns for a method dispatch on a 300Mhz PII which is only
  10ns slower than a direct function call on the same hardware.

This changes the new-bus ABI slightly so make sure you re-compile any
driver modules which you use.

1 files changed, 197 insertions, 0 deletions

diff --git a/sys/kern/subr_kobj.c b/sys/kern/subr_kobj.c
new file mode 100644
index 0000000..9a2eafb
--- /dev/null
+++ b/sys/kern/subr_kobj.c
@@ -0,0 +1,197 @@
+/*-
+ * Copyright (c) 2000 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/malloc.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/errno.h>
+#ifndef TEST
+#include <sys/systm.h>
+#endif
+#include <sys/kobj.h>
+
+#ifdef TEST
+#include "usertest.h"
+#endif
+
+static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
+
+#ifdef KOBJ_STATS
+
+#include <sys/sysctl.h>
+
+int kobj_lookup_hits;
+int kobj_lookup_misses;
+
+SYSCTL_INT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
+	   &kobj_lookup_hits, 0, "")
+SYSCTL_INT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
+	   &kobj_lookup_misses, 0, "")
+
+#endif
+
+static int kobj_next_id = 1;
+
+static int
+kobj_error_method(void)
+{
+	return ENXIO;
+}
+
+static void
+kobj_register_method(struct kobjop_desc *desc)
+{
+	if (desc->id == 0)
+		desc->id = kobj_next_id++;
+}
+
+static void
+kobj_unregister_method(struct kobjop_desc *desc)
+{
+}
+
+void
+kobj_class_compile(kobj_class_t cls)
+{
+	kobj_ops_t ops;
+	kobj_method_t *m;
+	int i;
+
+	/*
+	 * Don't do anything if we are already compiled.
+	 */
+	if (cls->ops)
+		return;
+
+	/*
+	 * First register any methods which need it.
+	 */
+	for (i = 0, m = cls->methods; m->desc; i++, m++)
+		kobj_register_method(m->desc);
+
+	/*
+	 * Then allocate the compiled op table.
+	 */
+	ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT);
+	if (!ops)
+		panic("kobj_compile_methods: out of memory");
+	bzero(ops, sizeof(struct kobj_ops));
+	ops->cls = cls;
+	cls->ops = ops;
+}
+
+void
+kobj_lookup_method(kobj_method_t *methods,
+		   kobj_method_t *ce,
+		   kobjop_desc_t desc)
+{
+	ce->desc = desc;
+	for (; methods && methods->desc; methods++) {
+		if (methods->desc == desc) {
+			ce->func = methods->func;
+			return;
+		}
+	}
+	if (desc->deflt)
+		ce->func = desc->deflt;
+	else
+		ce->func = kobj_error_method;
+	return;
+}
+
+void
+kobj_class_free(kobj_class_t cls)
+{
+	int i;
+	kobj_method_t *m;
+
+	/*
+	 * Unregister any methods which are no longer used.
+	 */
+	for (i = 0, m = cls->methods; m->desc; i++, m++)
+		kobj_unregister_method(m->desc);
+
+	/*
+	 * Free memory and clean up.
+	 */
+	free(cls->ops, M_KOBJ);
+	cls->ops = 0;
+}
+
+kobj_t
+kobj_create(kobj_class_t cls,
+	    struct malloc_type *mtype,
+	    int mflags)
+{
+	kobj_t obj;
+
+	/*
+	 * Allocate and initialise the new object.
+	 */
+	obj = malloc(cls->size, mtype, mflags);
+	if (!obj)
+		return 0;
+	bzero(obj, cls->size);
+	kobj_init(obj, cls);
+
+	return obj;
+}
+
+void
+kobj_init(kobj_t obj, kobj_class_t cls)
+{
+	/*
+	 * Consider compiling the class' method table.
+	 */
+	if (!cls->ops)
+		kobj_class_compile(cls);
+
+	obj->ops = cls->ops;
+	cls->instances++;
+}
+
+void
+kobj_delete(kobj_t obj, struct malloc_type *mtype)
+{
+	kobj_class_t cls = obj->ops->cls;
+
+	/*
+	 * Consider freeing the compiled method table for the class
+	 * after its last instance is deleted. As an optimisation, we
+	 * should defer this for a short while to avoid thrashing.
+	 */
+	cls->instances--;
+	if (!cls->instances)
+		kobj_class_free(cls);
+
+	obj->ops = 0;
+	if (mtype)
+		free(obj, mtype);
+}