refcount.c revision 91ebeef555ce7f899b6270a3c2df47b51f7ad59a
fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER START
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * The contents of this file are subject to the terms of the
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens * Common Development and Distribution License (the "License").
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens * You may not use this file except in compliance with the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
fa9e4066f08beec538e775443c5be79dd423fcabahrens * or http://www.opensolaris.org/os/licensing.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * See the License for the specific language governing permissions
fa9e4066f08beec538e775443c5be79dd423fcabahrens * and limitations under the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * When distributing Covered Code, include this CDDL HEADER in each
fa9e4066f08beec538e775443c5be79dd423fcabahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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fa9e4066f08beec538e775443c5be79dd423fcabahrens * information: Portions Copyright [yyyy] [name of copyright owner]
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER END
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * Use is subject to license terms.
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#pragma ident "%Z%%M% %I% %E% SMI"
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zfs_context.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/refcount.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#if defined(DEBUG) || !defined(_KERNEL)
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#ifdef _KERNEL
fa9e4066f08beec538e775443c5be79dd423fcabahrensint reference_tracking_enable = FALSE; /* runs out of memory too easily */
fa9e4066f08beec538e775443c5be79dd423fcabahrens#else
fa9e4066f08beec538e775443c5be79dd423fcabahrensint reference_tracking_enable = TRUE;
fa9e4066f08beec538e775443c5be79dd423fcabahrens#endif
fa9e4066f08beec538e775443c5be79dd423fcabahrensint reference_history = 4; /* tunable */
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic kmem_cache_t *reference_cache;
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic kmem_cache_t *reference_history_cache;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_init(void)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens reference_cache = kmem_cache_create("reference_cache",
fa9e4066f08beec538e775443c5be79dd423fcabahrens sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens reference_history_cache = kmem_cache_create("reference_history_cache",
fa9e4066f08beec538e775443c5be79dd423fcabahrens sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_fini(void)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_destroy(reference_cache);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_destroy(reference_history_cache);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_create(refcount_t *rc)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL);
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_create(&rc->rc_list, sizeof (reference_t),
fa9e4066f08beec538e775443c5be79dd423fcabahrens offsetof(reference_t, ref_link));
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_create(&rc->rc_removed, sizeof (reference_t),
fa9e4066f08beec538e775443c5be79dd423fcabahrens offsetof(reference_t, ref_link));
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens rc->rc_count = 0;
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens rc->rc_removed_count = 0;
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_destroy_many(refcount_t *rc, uint64_t number)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens reference_t *ref;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens ASSERT(rc->rc_count == number);
fa9e4066f08beec538e775443c5be79dd423fcabahrens while (ref = list_head(&rc->rc_list)) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_remove(&rc->rc_list, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_cache, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_destroy(&rc->rc_list);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens while (ref = list_head(&rc->rc_removed)) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_remove(&rc->rc_removed, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_history_cache, ref->ref_removed);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_cache, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_destroy(&rc->rc_removed);
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_destroy(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_destroy(refcount_t *rc)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens refcount_destroy_many(rc, 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_is_zero(refcount_t *rc)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens ASSERT(rc->rc_count >= 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (rc->rc_count == 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_count(refcount_t *rc)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens ASSERT(rc->rc_count >= 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (rc->rc_count);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_add_many(refcount_t *rc, uint64_t number, void *holder)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens reference_t *ref;
fa9e4066f08beec538e775443c5be79dd423fcabahrens int64_t count;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (reference_tracking_enable) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref = kmem_cache_alloc(reference_cache, KM_SLEEP);
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref->ref_holder = holder;
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref->ref_number = number;
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_enter(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens ASSERT(rc->rc_count >= 0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (reference_tracking_enable)
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_insert_head(&rc->rc_list, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens rc->rc_count += number;
fa9e4066f08beec538e775443c5be79dd423fcabahrens count = rc->rc_count;
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (count);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_add(refcount_t *rc, void *holder)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (refcount_add_many(rc, 1, holder));
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_remove_many(refcount_t *rc, uint64_t number, void *holder)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens reference_t *ref;
fa9e4066f08beec538e775443c5be79dd423fcabahrens int64_t count;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_enter(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens ASSERT(rc->rc_count >= number);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (!reference_tracking_enable) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens rc->rc_count -= number;
fa9e4066f08beec538e775443c5be79dd423fcabahrens count = rc->rc_count;
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (count);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens for (ref = list_head(&rc->rc_list); ref;
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref = list_next(&rc->rc_list, ref)) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (ref->ref_holder == holder && ref->ref_number == number) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_remove(&rc->rc_list, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (reference_history > 0) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref->ref_removed =
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_alloc(reference_history_cache,
fa9e4066f08beec538e775443c5be79dd423fcabahrens KM_SLEEP);
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_insert_head(&rc->rc_removed, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens rc->rc_removed_count++;
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (rc->rc_removed_count >= reference_history) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref = list_tail(&rc->rc_removed);
fa9e4066f08beec538e775443c5be79dd423fcabahrens list_remove(&rc->rc_removed, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_history_cache,
fa9e4066f08beec538e775443c5be79dd423fcabahrens ref->ref_removed);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_cache, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens rc->rc_removed_count--;
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens } else {
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_cache_free(reference_cache, ref);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens rc->rc_count -= number;
fa9e4066f08beec538e775443c5be79dd423fcabahrens count = rc->rc_count;
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&rc->rc_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (count);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens panic("No such hold %p on refcount %llx", holder,
fa9e4066f08beec538e775443c5be79dd423fcabahrens (u_longlong_t)(uintptr_t)rc);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (-1);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensrefcount_remove(refcount_t *rc, void *holder)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (refcount_remove_many(rc, 1, holder));
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#endif