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34dc7c2f BB |
1 | /* |
2 | * CDDL HEADER START | |
3 | * | |
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. | |
7 | * | |
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. | |
12 | * | |
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] | |
18 | * | |
19 | * CDDL HEADER END | |
20 | */ | |
21 | /* | |
428870ff | 22 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
34dc7c2f BB |
23 | */ |
24 | ||
34dc7c2f BB |
25 | #include <sys/zfs_context.h> |
26 | #include <sys/refcount.h> | |
27 | ||
572e2857 | 28 | #ifdef ZFS_DEBUG |
34dc7c2f BB |
29 | |
30 | #ifdef _KERNEL | |
31 | int reference_tracking_enable = FALSE; /* runs out of memory too easily */ | |
32 | #else | |
33 | int reference_tracking_enable = TRUE; | |
34 | #endif | |
35 | int reference_history = 4; /* tunable */ | |
36 | ||
37 | static kmem_cache_t *reference_cache; | |
38 | static kmem_cache_t *reference_history_cache; | |
39 | ||
40 | void | |
41 | refcount_init(void) | |
42 | { | |
43 | reference_cache = kmem_cache_create("reference_cache", | |
44 | sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); | |
45 | ||
46 | reference_history_cache = kmem_cache_create("reference_history_cache", | |
47 | sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); | |
48 | } | |
49 | ||
50 | void | |
51 | refcount_fini(void) | |
52 | { | |
53 | kmem_cache_destroy(reference_cache); | |
54 | kmem_cache_destroy(reference_history_cache); | |
55 | } | |
56 | ||
57 | void | |
58 | refcount_create(refcount_t *rc) | |
59 | { | |
60 | mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); | |
61 | list_create(&rc->rc_list, sizeof (reference_t), | |
62 | offsetof(reference_t, ref_link)); | |
63 | list_create(&rc->rc_removed, sizeof (reference_t), | |
64 | offsetof(reference_t, ref_link)); | |
65 | rc->rc_count = 0; | |
66 | rc->rc_removed_count = 0; | |
67 | } | |
68 | ||
69 | void | |
70 | refcount_destroy_many(refcount_t *rc, uint64_t number) | |
71 | { | |
72 | reference_t *ref; | |
73 | ||
74 | ASSERT(rc->rc_count == number); | |
75 | while (ref = list_head(&rc->rc_list)) { | |
76 | list_remove(&rc->rc_list, ref); | |
77 | kmem_cache_free(reference_cache, ref); | |
78 | } | |
79 | list_destroy(&rc->rc_list); | |
80 | ||
81 | while (ref = list_head(&rc->rc_removed)) { | |
82 | list_remove(&rc->rc_removed, ref); | |
83 | kmem_cache_free(reference_history_cache, ref->ref_removed); | |
84 | kmem_cache_free(reference_cache, ref); | |
85 | } | |
86 | list_destroy(&rc->rc_removed); | |
87 | mutex_destroy(&rc->rc_mtx); | |
88 | } | |
89 | ||
90 | void | |
91 | refcount_destroy(refcount_t *rc) | |
92 | { | |
93 | refcount_destroy_many(rc, 0); | |
94 | } | |
95 | ||
96 | int | |
97 | refcount_is_zero(refcount_t *rc) | |
98 | { | |
99 | ASSERT(rc->rc_count >= 0); | |
100 | return (rc->rc_count == 0); | |
101 | } | |
102 | ||
103 | int64_t | |
104 | refcount_count(refcount_t *rc) | |
105 | { | |
106 | ASSERT(rc->rc_count >= 0); | |
107 | return (rc->rc_count); | |
108 | } | |
109 | ||
110 | int64_t | |
111 | refcount_add_many(refcount_t *rc, uint64_t number, void *holder) | |
112 | { | |
113 | reference_t *ref; | |
114 | int64_t count; | |
115 | ||
116 | if (reference_tracking_enable) { | |
117 | ref = kmem_cache_alloc(reference_cache, KM_SLEEP); | |
118 | ref->ref_holder = holder; | |
119 | ref->ref_number = number; | |
120 | } | |
121 | mutex_enter(&rc->rc_mtx); | |
122 | ASSERT(rc->rc_count >= 0); | |
123 | if (reference_tracking_enable) | |
124 | list_insert_head(&rc->rc_list, ref); | |
125 | rc->rc_count += number; | |
126 | count = rc->rc_count; | |
127 | mutex_exit(&rc->rc_mtx); | |
128 | ||
129 | return (count); | |
130 | } | |
131 | ||
132 | int64_t | |
133 | refcount_add(refcount_t *rc, void *holder) | |
134 | { | |
135 | return (refcount_add_many(rc, 1, holder)); | |
136 | } | |
137 | ||
138 | int64_t | |
139 | refcount_remove_many(refcount_t *rc, uint64_t number, void *holder) | |
140 | { | |
141 | reference_t *ref; | |
142 | int64_t count; | |
143 | ||
144 | mutex_enter(&rc->rc_mtx); | |
145 | ASSERT(rc->rc_count >= number); | |
146 | ||
147 | if (!reference_tracking_enable) { | |
148 | rc->rc_count -= number; | |
149 | count = rc->rc_count; | |
150 | mutex_exit(&rc->rc_mtx); | |
151 | return (count); | |
152 | } | |
153 | ||
154 | for (ref = list_head(&rc->rc_list); ref; | |
155 | ref = list_next(&rc->rc_list, ref)) { | |
156 | if (ref->ref_holder == holder && ref->ref_number == number) { | |
157 | list_remove(&rc->rc_list, ref); | |
158 | if (reference_history > 0) { | |
159 | ref->ref_removed = | |
160 | kmem_cache_alloc(reference_history_cache, | |
161 | KM_SLEEP); | |
162 | list_insert_head(&rc->rc_removed, ref); | |
163 | rc->rc_removed_count++; | |
164 | if (rc->rc_removed_count >= reference_history) { | |
165 | ref = list_tail(&rc->rc_removed); | |
166 | list_remove(&rc->rc_removed, ref); | |
167 | kmem_cache_free(reference_history_cache, | |
168 | ref->ref_removed); | |
169 | kmem_cache_free(reference_cache, ref); | |
170 | rc->rc_removed_count--; | |
171 | } | |
172 | } else { | |
173 | kmem_cache_free(reference_cache, ref); | |
174 | } | |
175 | rc->rc_count -= number; | |
176 | count = rc->rc_count; | |
177 | mutex_exit(&rc->rc_mtx); | |
178 | return (count); | |
179 | } | |
180 | } | |
181 | panic("No such hold %p on refcount %llx", holder, | |
182 | (u_longlong_t)(uintptr_t)rc); | |
183 | return (-1); | |
184 | } | |
185 | ||
186 | int64_t | |
187 | refcount_remove(refcount_t *rc, void *holder) | |
188 | { | |
189 | return (refcount_remove_many(rc, 1, holder)); | |
190 | } | |
191 | ||
572e2857 BB |
192 | void |
193 | refcount_transfer(refcount_t *dst, refcount_t *src) | |
194 | { | |
195 | int64_t count, removed_count; | |
196 | list_t list, removed; | |
197 | ||
198 | list_create(&list, sizeof (reference_t), | |
199 | offsetof(reference_t, ref_link)); | |
200 | list_create(&removed, sizeof (reference_t), | |
201 | offsetof(reference_t, ref_link)); | |
202 | ||
203 | mutex_enter(&src->rc_mtx); | |
204 | count = src->rc_count; | |
205 | removed_count = src->rc_removed_count; | |
206 | src->rc_count = 0; | |
207 | src->rc_removed_count = 0; | |
208 | list_move_tail(&list, &src->rc_list); | |
209 | list_move_tail(&removed, &src->rc_removed); | |
210 | mutex_exit(&src->rc_mtx); | |
211 | ||
212 | mutex_enter(&dst->rc_mtx); | |
213 | dst->rc_count += count; | |
214 | dst->rc_removed_count += removed_count; | |
215 | list_move_tail(&dst->rc_list, &list); | |
216 | list_move_tail(&dst->rc_removed, &removed); | |
217 | mutex_exit(&dst->rc_mtx); | |
218 | ||
219 | list_destroy(&list); | |
220 | list_destroy(&removed); | |
221 | } | |
222 | ||
223 | #endif /* ZFS_DEBUG */ |