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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/zfs_context.h> 30 #include <sys/refcount.h> 31 32 #if defined(DEBUG) || !defined(_KERNEL) 33 34 #ifdef _KERNEL 35 int reference_tracking_enable = FALSE; /* runs out of memory too easily */ 36 #else 37 int reference_tracking_enable = TRUE; 38 #endif 39 int reference_history = 4; /* tunable */ 40 41 static kmem_cache_t *reference_cache; 42 static kmem_cache_t *reference_history_cache; 43 44 void 45 refcount_init(void) 46 { 47 reference_cache = kmem_cache_create("reference_cache", 48 sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 49 50 reference_history_cache = kmem_cache_create("reference_history_cache", 51 sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 52 } 53 54 void 55 refcount_fini(void) 56 { 57 kmem_cache_destroy(reference_cache); 58 kmem_cache_destroy(reference_history_cache); 59 } 60 61 void 62 refcount_create(refcount_t *rc) 63 { 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)); 68 mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); 69 } 70 71 void 72 refcount_destroy_many(refcount_t *rc, uint64_t number) 73 { 74 reference_t *ref; 75 76 ASSERT(rc->rc_count == number); 77 while (ref = list_head(&rc->rc_list)) { 78 list_remove(&rc->rc_list, ref); 79 kmem_cache_free(reference_cache, ref); 80 } 81 list_destroy(&rc->rc_list); 82 83 while (ref = list_head(&rc->rc_removed)) { 84 list_remove(&rc->rc_removed, ref); 85 kmem_cache_free(reference_history_cache, ref->ref_removed); 86 kmem_cache_free(reference_cache, ref); 87 } 88 list_destroy(&rc->rc_removed); 89 mutex_destroy(&rc->rc_mtx); 90 } 91 92 void 93 refcount_destroy(refcount_t *rc) 94 { 95 refcount_destroy_many(rc, 0); 96 } 97 98 int 99 refcount_is_zero(refcount_t *rc) 100 { 101 ASSERT(rc->rc_count >= 0); 102 return (rc->rc_count == 0); 103 } 104 105 int64_t 106 refcount_count(refcount_t *rc) 107 { 108 ASSERT(rc->rc_count >= 0); 109 return (rc->rc_count); 110 } 111 112 int64_t 113 refcount_add_many(refcount_t *rc, uint64_t number, void *holder) 114 { 115 reference_t *ref; 116 int64_t count; 117 118 if (reference_tracking_enable) { 119 ref = kmem_cache_alloc(reference_cache, KM_SLEEP); 120 ref->ref_holder = holder; 121 ref->ref_number = number; 122 } 123 mutex_enter(&rc->rc_mtx); 124 ASSERT(rc->rc_count >= 0); 125 if (reference_tracking_enable) 126 list_insert_head(&rc->rc_list, ref); 127 rc->rc_count += number; 128 count = rc->rc_count; 129 mutex_exit(&rc->rc_mtx); 130 131 return (count); 132 } 133 134 int64_t 135 refcount_add(refcount_t *rc, void *holder) 136 { 137 return (refcount_add_many(rc, 1, holder)); 138 } 139 140 int64_t 141 refcount_remove_many(refcount_t *rc, uint64_t number, void *holder) 142 { 143 reference_t *ref; 144 int64_t count; 145 146 mutex_enter(&rc->rc_mtx); 147 ASSERT(rc->rc_count >= number); 148 149 if (!reference_tracking_enable) { 150 rc->rc_count -= number; 151 count = rc->rc_count; 152 mutex_exit(&rc->rc_mtx); 153 return (count); 154 } 155 156 for (ref = list_head(&rc->rc_list); ref; 157 ref = list_next(&rc->rc_list, ref)) { 158 if (ref->ref_holder == holder && ref->ref_number == number) { 159 list_remove(&rc->rc_list, ref); 160 if (reference_history > 0) { 161 ref->ref_removed = 162 kmem_cache_alloc(reference_history_cache, 163 KM_SLEEP); 164 list_insert_head(&rc->rc_removed, ref); 165 rc->rc_removed_count++; 166 if (rc->rc_removed_count >= reference_history) { 167 ref = list_tail(&rc->rc_removed); 168 list_remove(&rc->rc_removed, ref); 169 kmem_cache_free(reference_history_cache, 170 ref->ref_removed); 171 kmem_cache_free(reference_cache, ref); 172 rc->rc_removed_count--; 173 } 174 } else { 175 kmem_cache_free(reference_cache, ref); 176 } 177 rc->rc_count -= number; 178 count = rc->rc_count; 179 mutex_exit(&rc->rc_mtx); 180 return (count); 181 } 182 } 183 panic("No such hold %p on refcount %llx", holder, 184 (u_longlong_t)(uintptr_t)rc); 185 return (-1); 186 } 187 188 int64_t 189 refcount_remove(refcount_t *rc, void *holder) 190 { 191 return (refcount_remove_many(rc, 1, holder)); 192 } 193 194 #endif 195