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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 | /* | |
22 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. | |
23 | * Copyright (c) 2012 by Delphix. All rights reserved. | |
24 | */ | |
25 | ||
26 | #include <sys/zfs_context.h> | |
27 | #include <sys/refcount.h> | |
28 | ||
29 | #ifdef ZFS_DEBUG | |
30 | ||
31 | #ifdef _KERNEL | |
32 | int reference_tracking_enable = FALSE; /* runs out of memory too easily */ | |
33 | #else | |
34 | int reference_tracking_enable = TRUE; | |
35 | #endif | |
36 | int reference_history = 3; /* tunable */ | |
37 | ||
38 | static kmem_cache_t *reference_cache; | |
39 | static kmem_cache_t *reference_history_cache; | |
40 | ||
41 | void | |
42 | refcount_init(void) | |
43 | { | |
44 | reference_cache = kmem_cache_create("reference_cache", | |
45 | sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); | |
46 | ||
47 | reference_history_cache = kmem_cache_create("reference_history_cache", | |
48 | sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); | |
49 | } | |
50 | ||
51 | void | |
52 | refcount_fini(void) | |
53 | { | |
54 | kmem_cache_destroy(reference_cache); | |
55 | kmem_cache_destroy(reference_history_cache); | |
56 | } | |
57 | ||
58 | void | |
59 | refcount_create(refcount_t *rc) | |
60 | { | |
61 | mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); | |
62 | list_create(&rc->rc_list, sizeof (reference_t), | |
63 | offsetof(reference_t, ref_link)); | |
64 | list_create(&rc->rc_removed, sizeof (reference_t), | |
65 | offsetof(reference_t, ref_link)); | |
66 | rc->rc_count = 0; | |
67 | rc->rc_removed_count = 0; | |
68 | rc->rc_tracked = reference_tracking_enable; | |
69 | } | |
70 | ||
71 | void | |
72 | refcount_create_untracked(refcount_t *rc) | |
73 | { | |
74 | refcount_create(rc); | |
75 | rc->rc_tracked = B_FALSE; | |
76 | } | |
77 | ||
78 | void | |
79 | refcount_destroy_many(refcount_t *rc, uint64_t number) | |
80 | { | |
81 | reference_t *ref; | |
82 | ||
83 | ASSERT(rc->rc_count == number); | |
84 | while ((ref = list_head(&rc->rc_list))) { | |
85 | list_remove(&rc->rc_list, ref); | |
86 | kmem_cache_free(reference_cache, ref); | |
87 | } | |
88 | list_destroy(&rc->rc_list); | |
89 | ||
90 | while ((ref = list_head(&rc->rc_removed))) { | |
91 | list_remove(&rc->rc_removed, ref); | |
92 | kmem_cache_free(reference_history_cache, ref->ref_removed); | |
93 | kmem_cache_free(reference_cache, ref); | |
94 | } | |
95 | list_destroy(&rc->rc_removed); | |
96 | mutex_destroy(&rc->rc_mtx); | |
97 | } | |
98 | ||
99 | void | |
100 | refcount_destroy(refcount_t *rc) | |
101 | { | |
102 | refcount_destroy_many(rc, 0); | |
103 | } | |
104 | ||
105 | int | |
106 | refcount_is_zero(refcount_t *rc) | |
107 | { | |
108 | return (rc->rc_count == 0); | |
109 | } | |
110 | ||
111 | int64_t | |
112 | refcount_count(refcount_t *rc) | |
113 | { | |
114 | return (rc->rc_count); | |
115 | } | |
116 | ||
117 | int64_t | |
118 | refcount_add_many(refcount_t *rc, uint64_t number, void *holder) | |
119 | { | |
120 | reference_t *ref = NULL; | |
121 | int64_t count; | |
122 | ||
123 | if (rc->rc_tracked) { | |
124 | ref = kmem_cache_alloc(reference_cache, KM_SLEEP); | |
125 | ref->ref_holder = holder; | |
126 | ref->ref_number = number; | |
127 | } | |
128 | mutex_enter(&rc->rc_mtx); | |
129 | ASSERT(rc->rc_count >= 0); | |
130 | if (rc->rc_tracked) | |
131 | list_insert_head(&rc->rc_list, ref); | |
132 | rc->rc_count += number; | |
133 | count = rc->rc_count; | |
134 | mutex_exit(&rc->rc_mtx); | |
135 | ||
136 | return (count); | |
137 | } | |
138 | ||
139 | int64_t | |
3e990ae0 | 140 | zfs_refcount_add(refcount_t *rc, void *holder) |
87d546d8 TG |
141 | { |
142 | return (refcount_add_many(rc, 1, holder)); | |
143 | } | |
144 | ||
145 | int64_t | |
146 | refcount_remove_many(refcount_t *rc, uint64_t number, void *holder) | |
147 | { | |
148 | reference_t *ref; | |
149 | int64_t count; | |
150 | ||
151 | mutex_enter(&rc->rc_mtx); | |
152 | ASSERT(rc->rc_count >= number); | |
153 | ||
154 | if (!rc->rc_tracked) { | |
155 | rc->rc_count -= number; | |
156 | count = rc->rc_count; | |
157 | mutex_exit(&rc->rc_mtx); | |
158 | return (count); | |
159 | } | |
160 | ||
161 | for (ref = list_head(&rc->rc_list); ref; | |
162 | ref = list_next(&rc->rc_list, ref)) { | |
163 | if (ref->ref_holder == holder && ref->ref_number == number) { | |
164 | list_remove(&rc->rc_list, ref); | |
165 | if (reference_history > 0) { | |
166 | ref->ref_removed = | |
167 | kmem_cache_alloc(reference_history_cache, | |
168 | KM_SLEEP); | |
169 | list_insert_head(&rc->rc_removed, ref); | |
170 | rc->rc_removed_count++; | |
171 | if (rc->rc_removed_count > reference_history) { | |
172 | ref = list_tail(&rc->rc_removed); | |
173 | list_remove(&rc->rc_removed, ref); | |
174 | kmem_cache_free(reference_history_cache, | |
175 | ref->ref_removed); | |
176 | kmem_cache_free(reference_cache, ref); | |
177 | rc->rc_removed_count--; | |
178 | } | |
179 | } else { | |
180 | kmem_cache_free(reference_cache, ref); | |
181 | } | |
182 | rc->rc_count -= number; | |
183 | count = rc->rc_count; | |
184 | mutex_exit(&rc->rc_mtx); | |
185 | return (count); | |
186 | } | |
187 | } | |
188 | panic("No such hold %p on refcount %llx", holder, | |
189 | (u_longlong_t)(uintptr_t)rc); | |
190 | return (-1); | |
191 | } | |
192 | ||
193 | int64_t | |
194 | refcount_remove(refcount_t *rc, void *holder) | |
195 | { | |
196 | return (refcount_remove_many(rc, 1, holder)); | |
197 | } | |
198 | ||
199 | void | |
200 | refcount_transfer(refcount_t *dst, refcount_t *src) | |
201 | { | |
202 | int64_t count, removed_count; | |
203 | list_t list, removed; | |
204 | ||
205 | list_create(&list, sizeof (reference_t), | |
206 | offsetof(reference_t, ref_link)); | |
207 | list_create(&removed, sizeof (reference_t), | |
208 | offsetof(reference_t, ref_link)); | |
209 | ||
210 | mutex_enter(&src->rc_mtx); | |
211 | count = src->rc_count; | |
212 | removed_count = src->rc_removed_count; | |
213 | src->rc_count = 0; | |
214 | src->rc_removed_count = 0; | |
215 | list_move_tail(&list, &src->rc_list); | |
216 | list_move_tail(&removed, &src->rc_removed); | |
217 | mutex_exit(&src->rc_mtx); | |
218 | ||
219 | mutex_enter(&dst->rc_mtx); | |
220 | dst->rc_count += count; | |
221 | dst->rc_removed_count += removed_count; | |
222 | list_move_tail(&dst->rc_list, &list); | |
223 | list_move_tail(&dst->rc_removed, &removed); | |
224 | mutex_exit(&dst->rc_mtx); | |
225 | ||
226 | list_destroy(&list); | |
227 | list_destroy(&removed); | |
228 | } | |
229 | ||
230 | #endif /* ZFS_DEBUG */ |