4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
26 #pragma ident "@(#)refcount.c 1.2 07/08/02 SMI"
28 #include <sys/zfs_context.h>
29 #include <sys/refcount.h>
31 #if defined(DEBUG) || !defined(_KERNEL)
34 int reference_tracking_enable = FALSE; /* runs out of memory too easily */
36 int reference_tracking_enable = TRUE;
38 int reference_history = 4; /* tunable */
40 static kmem_cache_t *reference_cache;
41 static kmem_cache_t *reference_history_cache;
46 reference_cache = kmem_cache_create("reference_cache",
47 sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
49 reference_history_cache = kmem_cache_create("reference_history_cache",
50 sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
56 kmem_cache_destroy(reference_cache);
57 kmem_cache_destroy(reference_history_cache);
61 refcount_create(refcount_t *rc)
63 mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL);
64 list_create(&rc->rc_list, sizeof (reference_t),
65 offsetof(reference_t, ref_link));
66 list_create(&rc->rc_removed, sizeof (reference_t),
67 offsetof(reference_t, ref_link));
69 rc->rc_removed_count = 0;
73 refcount_destroy_many(refcount_t *rc, uint64_t number)
77 ASSERT(rc->rc_count == number);
78 while (ref = list_head(&rc->rc_list)) {
79 list_remove(&rc->rc_list, ref);
80 kmem_cache_free(reference_cache, ref);
82 list_destroy(&rc->rc_list);
84 while (ref = list_head(&rc->rc_removed)) {
85 list_remove(&rc->rc_removed, ref);
86 kmem_cache_free(reference_history_cache, ref->ref_removed);
87 kmem_cache_free(reference_cache, ref);
89 list_destroy(&rc->rc_removed);
90 mutex_destroy(&rc->rc_mtx);
94 refcount_destroy(refcount_t *rc)
96 refcount_destroy_many(rc, 0);
100 refcount_is_zero(refcount_t *rc)
102 ASSERT(rc->rc_count >= 0);
103 return (rc->rc_count == 0);
107 refcount_count(refcount_t *rc)
109 ASSERT(rc->rc_count >= 0);
110 return (rc->rc_count);
114 refcount_add_many(refcount_t *rc, uint64_t number, void *holder)
119 if (reference_tracking_enable) {
120 ref = kmem_cache_alloc(reference_cache, KM_SLEEP);
121 ref->ref_holder = holder;
122 ref->ref_number = number;
124 mutex_enter(&rc->rc_mtx);
125 ASSERT(rc->rc_count >= 0);
126 if (reference_tracking_enable)
127 list_insert_head(&rc->rc_list, ref);
128 rc->rc_count += number;
129 count = rc->rc_count;
130 mutex_exit(&rc->rc_mtx);
136 refcount_add(refcount_t *rc, void *holder)
138 return (refcount_add_many(rc, 1, holder));
142 refcount_remove_many(refcount_t *rc, uint64_t number, void *holder)
147 mutex_enter(&rc->rc_mtx);
148 ASSERT(rc->rc_count >= number);
150 if (!reference_tracking_enable) {
151 rc->rc_count -= number;
152 count = rc->rc_count;
153 mutex_exit(&rc->rc_mtx);
157 for (ref = list_head(&rc->rc_list); ref;
158 ref = list_next(&rc->rc_list, ref)) {
159 if (ref->ref_holder == holder && ref->ref_number == number) {
160 list_remove(&rc->rc_list, ref);
161 if (reference_history > 0) {
163 kmem_cache_alloc(reference_history_cache,
165 list_insert_head(&rc->rc_removed, ref);
166 rc->rc_removed_count++;
167 if (rc->rc_removed_count >= reference_history) {
168 ref = list_tail(&rc->rc_removed);
169 list_remove(&rc->rc_removed, ref);
170 kmem_cache_free(reference_history_cache,
172 kmem_cache_free(reference_cache, ref);
173 rc->rc_removed_count--;
176 kmem_cache_free(reference_cache, ref);
178 rc->rc_count -= number;
179 count = rc->rc_count;
180 mutex_exit(&rc->rc_mtx);
184 panic("No such hold %p on refcount %llx", holder,
185 (u_longlong_t)(uintptr_t)rc);
190 refcount_remove(refcount_t *rc, void *holder)
192 return (refcount_remove_many(rc, 1, holder));