metaslab_impl.h revision 260768 
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 2009 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26/*
27 * Copyright (c) 2013 by Delphix. All rights reserved.
28 */
29
30#ifndef _SYS_METASLAB_IMPL_H
31#define	_SYS_METASLAB_IMPL_H
32
33#include <sys/metaslab.h>
34#include <sys/space_map.h>
35#include <sys/vdev.h>
36#include <sys/txg.h>
37#include <sys/avl.h>
38
39#ifdef	__cplusplus
40extern "C" {
41#endif
42
43struct metaslab_class {
44	spa_t			*mc_spa;
45	metaslab_group_t	*mc_rotor;
46	space_map_ops_t		*mc_ops;
47	uint64_t		mc_aliquot;
48	uint64_t		mc_alloc_groups; /* # of allocatable groups */
49	uint64_t		mc_alloc;	/* total allocated space */
50	uint64_t		mc_deferred;	/* total deferred frees */
51	uint64_t		mc_space;	/* total space (alloc + free) */
52	uint64_t		mc_dspace;	/* total deflated space */
53	uint64_t		mc_minblocksize;
54};
55
56struct metaslab_group {
57	kmutex_t		mg_lock;
58	avl_tree_t		mg_metaslab_tree;
59	uint64_t		mg_aliquot;
60	uint64_t		mg_bonus_area;
61	uint64_t		mg_alloc_failures;
62	boolean_t		mg_allocatable;		/* can we allocate? */
63	uint64_t		mg_free_capacity;	/* percentage free */
64	int64_t			mg_bias;
65	int64_t			mg_activation_count;
66	metaslab_class_t	*mg_class;
67	vdev_t			*mg_vd;
68	metaslab_group_t	*mg_prev;
69	metaslab_group_t	*mg_next;
70};
71
72/*
73 * Each metaslab maintains an in-core free map (ms_map) that contains the
74 * current list of free segments. As blocks are allocated, the allocated
75 * segment is removed from the ms_map and added to a per txg allocation map.
76 * As blocks are freed, they are added to the per txg free map. These per
77 * txg maps allow us to process all allocations and frees in syncing context
78 * where it is safe to update the on-disk space maps.
79 *
80 * Each metaslab's free space is tracked in a space map object in the MOS,
81 * which is only updated in syncing context. Each time we sync a txg,
82 * we append the allocs and frees from that txg to the space map object.
83 * When the txg is done syncing, metaslab_sync_done() updates ms_smo
84 * to ms_smo_syncing. Everything in ms_smo is always safe to allocate.
85 *
86 * To load the in-core free map we read the space map object from disk.
87 * This object contains a series of alloc and free records that are
88 * combined to make up the list of all free segments in this metaslab. These
89 * segments are represented in-core by the ms_map and are stored in an
90 * AVL tree.
91 *
92 * As the space map objects grows (as a result of the appends) it will
93 * eventually become space-inefficient. When the space map object is
94 * zfs_condense_pct/100 times the size of the minimal on-disk representation,
95 * we rewrite it in its minimized form.
96 */
97struct metaslab {
98	kmutex_t	ms_lock;	/* metaslab lock		*/
99	space_map_obj_t	ms_smo;		/* synced space map object	*/
100	space_map_obj_t	ms_smo_syncing;	/* syncing space map object	*/
101	space_map_t	*ms_allocmap[TXG_SIZE];	/* allocated this txg	*/
102	space_map_t	*ms_freemap[TXG_SIZE];	/* freed this txg	*/
103	space_map_t	*ms_defermap[TXG_DEFER_SIZE];	/* deferred frees */
104	space_map_t	*ms_map;	/* in-core free space map	*/
105	int64_t		ms_deferspace;	/* sum of ms_defermap[] space	*/
106	uint64_t	ms_weight;	/* weight vs. others in group	*/
107	metaslab_group_t *ms_group;	/* metaslab group		*/
108	avl_node_t	ms_group_node;	/* node in metaslab group tree	*/
109	txg_node_t	ms_txg_node;	/* per-txg dirty metaslab links	*/
110};
111
112#ifdef	__cplusplus
113}
114#endif
115
116#endif	/* _SYS_METASLAB_IMPL_H */
117