1168404Spjd/* 2168404Spjd * CDDL HEADER START 3168404Spjd * 4168404Spjd * The contents of this file are subject to the terms of the 5185029Spjd * Common Development and Distribution License (the "License"). 6185029Spjd * You may not use this file except in compliance with the License. 7168404Spjd * 8168404Spjd * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9168404Spjd * or http://www.opensolaris.org/os/licensing. 10168404Spjd * See the License for the specific language governing permissions 11168404Spjd * and limitations under the License. 12168404Spjd * 13168404Spjd * When distributing Covered Code, include this CDDL HEADER in each 14168404Spjd * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15168404Spjd * If applicable, add the following below this CDDL HEADER, with the 16168404Spjd * fields enclosed by brackets "[]" replaced with your own identifying 17168404Spjd * information: Portions Copyright [yyyy] [name of copyright owner] 18168404Spjd * 19168404Spjd * CDDL HEADER END 20168404Spjd */ 21168404Spjd/* 22219089Spjd * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23248571Smm * Copyright (c) 2012 by Delphix. All rights reserved. 24168404Spjd */ 25168404Spjd 26168404Spjd#include <sys/zfs_context.h> 27168404Spjd#include <sys/refcount.h> 28168404Spjd 29219089Spjd#ifdef ZFS_DEBUG 30168404Spjd 31168404Spjd#ifdef _KERNEL 32168404Spjdint reference_tracking_enable = FALSE; /* runs out of memory too easily */ 33168404Spjd#else 34168404Spjdint reference_tracking_enable = TRUE; 35168404Spjd#endif 36248571Smmint reference_history = 3; /* tunable */ 37168404Spjd 38168404Spjdstatic kmem_cache_t *reference_cache; 39168404Spjdstatic kmem_cache_t *reference_history_cache; 40168404Spjd 41168404Spjdvoid 42179310Spjdrefcount_sysinit(void) 43168404Spjd{ 44168404Spjd reference_cache = kmem_cache_create("reference_cache", 45168404Spjd sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 46168404Spjd 47168404Spjd reference_history_cache = kmem_cache_create("reference_history_cache", 48168404Spjd sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 49168404Spjd} 50168404Spjd 51168404Spjdvoid 52168404Spjdrefcount_fini(void) 53168404Spjd{ 54168404Spjd kmem_cache_destroy(reference_cache); 55168404Spjd kmem_cache_destroy(reference_history_cache); 56168404Spjd} 57168404Spjd 58168404Spjdvoid 59168404Spjdrefcount_create(refcount_t *rc) 60168404Spjd{ 61185029Spjd mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); 62168404Spjd list_create(&rc->rc_list, sizeof (reference_t), 63168404Spjd offsetof(reference_t, ref_link)); 64168404Spjd list_create(&rc->rc_removed, sizeof (reference_t), 65168404Spjd offsetof(reference_t, ref_link)); 66185029Spjd rc->rc_count = 0; 67185029Spjd rc->rc_removed_count = 0; 68248571Smm rc->rc_tracked = reference_tracking_enable; 69168404Spjd} 70168404Spjd 71168404Spjdvoid 72248571Smmrefcount_create_untracked(refcount_t *rc) 73248571Smm{ 74248571Smm refcount_create(rc); 75248571Smm rc->rc_tracked = B_FALSE; 76248571Smm} 77248571Smm 78248571Smmvoid 79168404Spjdrefcount_destroy_many(refcount_t *rc, uint64_t number) 80168404Spjd{ 81168404Spjd reference_t *ref; 82168404Spjd 83168404Spjd ASSERT(rc->rc_count == number); 84168404Spjd while (ref = list_head(&rc->rc_list)) { 85168404Spjd list_remove(&rc->rc_list, ref); 86168404Spjd kmem_cache_free(reference_cache, ref); 87168404Spjd } 88168404Spjd list_destroy(&rc->rc_list); 89168404Spjd 90168404Spjd while (ref = list_head(&rc->rc_removed)) { 91168404Spjd list_remove(&rc->rc_removed, ref); 92168404Spjd kmem_cache_free(reference_history_cache, ref->ref_removed); 93168404Spjd kmem_cache_free(reference_cache, ref); 94168404Spjd } 95168404Spjd list_destroy(&rc->rc_removed); 96168404Spjd mutex_destroy(&rc->rc_mtx); 97168404Spjd} 98168404Spjd 99168404Spjdvoid 100168404Spjdrefcount_destroy(refcount_t *rc) 101168404Spjd{ 102168404Spjd refcount_destroy_many(rc, 0); 103168404Spjd} 104168404Spjd 105168404Spjdint 106168404Spjdrefcount_is_zero(refcount_t *rc) 107168404Spjd{ 108168404Spjd return (rc->rc_count == 0); 109168404Spjd} 110168404Spjd 111168404Spjdint64_t 112168404Spjdrefcount_count(refcount_t *rc) 113168404Spjd{ 114168404Spjd return (rc->rc_count); 115168404Spjd} 116168404Spjd 117168404Spjdint64_t 118168404Spjdrefcount_add_many(refcount_t *rc, uint64_t number, void *holder) 119168404Spjd{ 120247187Smm reference_t *ref = NULL; 121168404Spjd int64_t count; 122168404Spjd 123248571Smm if (rc->rc_tracked) { 124168404Spjd ref = kmem_cache_alloc(reference_cache, KM_SLEEP); 125168404Spjd ref->ref_holder = holder; 126168404Spjd ref->ref_number = number; 127168404Spjd } 128168404Spjd mutex_enter(&rc->rc_mtx); 129168404Spjd ASSERT(rc->rc_count >= 0); 130248571Smm if (rc->rc_tracked) 131168404Spjd list_insert_head(&rc->rc_list, ref); 132168404Spjd rc->rc_count += number; 133168404Spjd count = rc->rc_count; 134168404Spjd mutex_exit(&rc->rc_mtx); 135168404Spjd 136168404Spjd return (count); 137168404Spjd} 138168404Spjd 139168404Spjdint64_t 140168404Spjdrefcount_add(refcount_t *rc, void *holder) 141168404Spjd{ 142168404Spjd return (refcount_add_many(rc, 1, holder)); 143168404Spjd} 144168404Spjd 145168404Spjdint64_t 146168404Spjdrefcount_remove_many(refcount_t *rc, uint64_t number, void *holder) 147168404Spjd{ 148168404Spjd reference_t *ref; 149168404Spjd int64_t count; 150168404Spjd 151168404Spjd mutex_enter(&rc->rc_mtx); 152168404Spjd ASSERT(rc->rc_count >= number); 153168404Spjd 154248571Smm if (!rc->rc_tracked) { 155168404Spjd rc->rc_count -= number; 156168404Spjd count = rc->rc_count; 157168404Spjd mutex_exit(&rc->rc_mtx); 158168404Spjd return (count); 159168404Spjd } 160168404Spjd 161168404Spjd for (ref = list_head(&rc->rc_list); ref; 162168404Spjd ref = list_next(&rc->rc_list, ref)) { 163168404Spjd if (ref->ref_holder == holder && ref->ref_number == number) { 164168404Spjd list_remove(&rc->rc_list, ref); 165168404Spjd if (reference_history > 0) { 166168404Spjd ref->ref_removed = 167168404Spjd kmem_cache_alloc(reference_history_cache, 168168404Spjd KM_SLEEP); 169168404Spjd list_insert_head(&rc->rc_removed, ref); 170168404Spjd rc->rc_removed_count++; 171248571Smm if (rc->rc_removed_count > reference_history) { 172168404Spjd ref = list_tail(&rc->rc_removed); 173168404Spjd list_remove(&rc->rc_removed, ref); 174168404Spjd kmem_cache_free(reference_history_cache, 175168404Spjd ref->ref_removed); 176168404Spjd kmem_cache_free(reference_cache, ref); 177168404Spjd rc->rc_removed_count--; 178168404Spjd } 179168404Spjd } else { 180168404Spjd kmem_cache_free(reference_cache, ref); 181168404Spjd } 182168404Spjd rc->rc_count -= number; 183168404Spjd count = rc->rc_count; 184168404Spjd mutex_exit(&rc->rc_mtx); 185168404Spjd return (count); 186168404Spjd } 187168404Spjd } 188168404Spjd panic("No such hold %p on refcount %llx", holder, 189168404Spjd (u_longlong_t)(uintptr_t)rc); 190168404Spjd return (-1); 191168404Spjd} 192168404Spjd 193168404Spjdint64_t 194168404Spjdrefcount_remove(refcount_t *rc, void *holder) 195168404Spjd{ 196168404Spjd return (refcount_remove_many(rc, 1, holder)); 197168404Spjd} 198168404Spjd 199219089Spjdvoid 200219089Spjdrefcount_transfer(refcount_t *dst, refcount_t *src) 201219089Spjd{ 202219089Spjd int64_t count, removed_count; 203219089Spjd list_t list, removed; 204219089Spjd 205219089Spjd list_create(&list, sizeof (reference_t), 206219089Spjd offsetof(reference_t, ref_link)); 207219089Spjd list_create(&removed, sizeof (reference_t), 208219089Spjd offsetof(reference_t, ref_link)); 209219089Spjd 210219089Spjd mutex_enter(&src->rc_mtx); 211219089Spjd count = src->rc_count; 212219089Spjd removed_count = src->rc_removed_count; 213219089Spjd src->rc_count = 0; 214219089Spjd src->rc_removed_count = 0; 215219089Spjd list_move_tail(&list, &src->rc_list); 216219089Spjd list_move_tail(&removed, &src->rc_removed); 217219089Spjd mutex_exit(&src->rc_mtx); 218219089Spjd 219219089Spjd mutex_enter(&dst->rc_mtx); 220219089Spjd dst->rc_count += count; 221219089Spjd dst->rc_removed_count += removed_count; 222219089Spjd list_move_tail(&dst->rc_list, &list); 223219089Spjd list_move_tail(&dst->rc_removed, &removed); 224219089Spjd mutex_exit(&dst->rc_mtx); 225219089Spjd 226219089Spjd list_destroy(&list); 227219089Spjd list_destroy(&removed); 228219089Spjd} 229219089Spjd 230219089Spjd#endif /* ZFS_DEBUG */ 231