diff options
Diffstat (limited to 'module/zfs/refcount.c')
| -rw-r--r-- | module/zfs/refcount.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/module/zfs/refcount.c b/module/zfs/refcount.c new file mode 100644 index 000000000..f1b3b23fe --- /dev/null +++ b/module/zfs/refcount.c @@ -0,0 +1,195 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2007 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#include <sys/zfs_context.h> +#include <sys/refcount.h> + +#if defined(DEBUG) || !defined(_KERNEL) + +#ifdef _KERNEL +int reference_tracking_enable = FALSE; /* runs out of memory too easily */ +#else +int reference_tracking_enable = TRUE; +#endif +int reference_history = 4; /* tunable */ + +static kmem_cache_t *reference_cache; +static kmem_cache_t *reference_history_cache; + +void +refcount_init(void) +{ + reference_cache = kmem_cache_create("reference_cache", + sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); + + reference_history_cache = kmem_cache_create("reference_history_cache", + sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); +} + +void +refcount_fini(void) +{ + kmem_cache_destroy(reference_cache); + kmem_cache_destroy(reference_history_cache); +} + +void +refcount_create(refcount_t *rc) +{ + mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); + list_create(&rc->rc_list, sizeof (reference_t), + offsetof(reference_t, ref_link)); + list_create(&rc->rc_removed, sizeof (reference_t), + offsetof(reference_t, ref_link)); + rc->rc_count = 0; + rc->rc_removed_count = 0; +} + +void +refcount_destroy_many(refcount_t *rc, uint64_t number) +{ + reference_t *ref; + + ASSERT(rc->rc_count == number); + while (ref = list_head(&rc->rc_list)) { + list_remove(&rc->rc_list, ref); + kmem_cache_free(reference_cache, ref); + } + list_destroy(&rc->rc_list); + + while (ref = list_head(&rc->rc_removed)) { + list_remove(&rc->rc_removed, ref); + kmem_cache_free(reference_history_cache, ref->ref_removed); + kmem_cache_free(reference_cache, ref); + } + list_destroy(&rc->rc_removed); + mutex_destroy(&rc->rc_mtx); +} + +void +refcount_destroy(refcount_t *rc) +{ + refcount_destroy_many(rc, 0); +} + +int +refcount_is_zero(refcount_t *rc) +{ + ASSERT(rc->rc_count >= 0); + return (rc->rc_count == 0); +} + +int64_t +refcount_count(refcount_t *rc) +{ + ASSERT(rc->rc_count >= 0); + return (rc->rc_count); +} + +int64_t +refcount_add_many(refcount_t *rc, uint64_t number, void *holder) +{ + reference_t *ref; + int64_t count; + + if (reference_tracking_enable) { + ref = kmem_cache_alloc(reference_cache, KM_SLEEP); + ref->ref_holder = holder; + ref->ref_number = number; + } + mutex_enter(&rc->rc_mtx); + ASSERT(rc->rc_count >= 0); + if (reference_tracking_enable) + list_insert_head(&rc->rc_list, ref); + rc->rc_count += number; + count = rc->rc_count; + mutex_exit(&rc->rc_mtx); + + return (count); +} + +int64_t +refcount_add(refcount_t *rc, void *holder) +{ + return (refcount_add_many(rc, 1, holder)); +} + +int64_t +refcount_remove_many(refcount_t *rc, uint64_t number, void *holder) +{ + reference_t *ref; + int64_t count; + + mutex_enter(&rc->rc_mtx); + ASSERT(rc->rc_count >= number); + + if (!reference_tracking_enable) { + rc->rc_count -= number; + count = rc->rc_count; + mutex_exit(&rc->rc_mtx); + return (count); + } + + for (ref = list_head(&rc->rc_list); ref; + ref = list_next(&rc->rc_list, ref)) { + if (ref->ref_holder == holder && ref->ref_number == number) { + list_remove(&rc->rc_list, ref); + if (reference_history > 0) { + ref->ref_removed = + kmem_cache_alloc(reference_history_cache, + KM_SLEEP); + list_insert_head(&rc->rc_removed, ref); + rc->rc_removed_count++; + if (rc->rc_removed_count >= reference_history) { + ref = list_tail(&rc->rc_removed); + list_remove(&rc->rc_removed, ref); + kmem_cache_free(reference_history_cache, + ref->ref_removed); + kmem_cache_free(reference_cache, ref); + rc->rc_removed_count--; + } + } else { + kmem_cache_free(reference_cache, ref); + } + rc->rc_count -= number; + count = rc->rc_count; + mutex_exit(&rc->rc_mtx); + return (count); + } + } + panic("No such hold %p on refcount %llx", holder, + (u_longlong_t)(uintptr_t)rc); + return (-1); +} + +int64_t +refcount_remove(refcount_t *rc, void *holder) +{ + return (refcount_remove_many(rc, 1, holder)); +} + +#endif |