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_SPACE_MAP_H
31 #define _SYS_SPACE_MAP_H
32
33 #include <sys/avl.h>
34 #include <sys/range_tree.h>
35 #include <sys/dmu.h>
36
37 #ifdef __cplusplus
38 extern "C" {
39 #endif
40
41 /*
42 * The size of the space map object has increased to include a histogram.
43 * The SPACE_MAP_SIZE_V0 designates the original size and is used to
44 * maintain backward compatibility.
45 */
46 #define SPACE_MAP_SIZE_V0 (3 * sizeof (uint64_t))
47 #define SPACE_MAP_HISTOGRAM_SIZE(sm) \
48 (sizeof ((sm)->sm_phys->smp_histogram) / \
49 sizeof ((sm)->sm_phys->smp_histogram[0]))
50
51 /*
52 * The space_map_phys is the on-disk representation of the space map.
53 * Consumers of space maps should never reference any of the members of this
54 * structure directly. These members may only be updated in syncing context.
55 *
56 * Note the smp_object is no longer used but remains in the structure
57 * for backward compatibility.
58 */
59 typedef struct space_map_phys {
60 uint64_t smp_object; /* on-disk space map object */
61 uint64_t smp_objsize; /* size of the object */
62 uint64_t smp_alloc; /* space allocated from the map */
63 uint64_t smp_pad[5]; /* reserved */
64
65 /*
66 * The smp_histogram maintains a histogram of free regions. Each
67 * bucket, smp_histogram[i], contains the number of free regions
68 * whose size is:
69 * 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
70 */
71 uint64_t smp_histogram[32]; /* histogram of free space */
72 } space_map_phys_t;
73
74 /*
75 * The space map object defines a region of space, its size, how much is
76 * allocated, and the on-disk object that stores this information.
77 * Consumers of space maps may only access the members of this structure.
78 */
79 typedef struct space_map {
80 uint64_t sm_start; /* start of map */
81 uint64_t sm_size; /* size of map */
82 uint8_t sm_shift; /* unit shift */
83 uint64_t sm_length; /* synced length */
84 uint64_t sm_alloc; /* synced space allocated */
85 objset_t *sm_os; /* objset for this map */
86 uint64_t sm_object; /* object id for this map */
87 uint32_t sm_blksz; /* block size for space map */
88 dmu_buf_t *sm_dbuf; /* space_map_phys_t dbuf */
89 space_map_phys_t *sm_phys; /* on-disk space map */
90 kmutex_t *sm_lock; /* pointer to lock that protects map */
91 } space_map_t;
92
93 /*
94 * debug entry
95 *
96 * 1 3 10 50
97 * ,---+--------+------------+---------------------------------.
98 * | 1 | action | syncpass | txg (lower bits) |
99 * `---+--------+------------+---------------------------------'
100 * 63 62 60 59 50 49 0
101 *
102 *
103 * non-debug entry
104 *
105 * 1 47 1 15
106 * ,-----------------------------------------------------------.
107 * | 0 | offset (sm_shift units) | type | run |
108 * `-----------------------------------------------------------'
109 * 63 62 17 16 15 0
110 */
111
112 /* All this stuff takes and returns bytes */
113 #define SM_RUN_DECODE(x) (BF64_DECODE(x, 0, 15) + 1)
114 #define SM_RUN_ENCODE(x) BF64_ENCODE((x) - 1, 0, 15)
115 #define SM_TYPE_DECODE(x) BF64_DECODE(x, 15, 1)
116 #define SM_TYPE_ENCODE(x) BF64_ENCODE(x, 15, 1)
117 #define SM_OFFSET_DECODE(x) BF64_DECODE(x, 16, 47)
118 #define SM_OFFSET_ENCODE(x) BF64_ENCODE(x, 16, 47)
119 #define SM_DEBUG_DECODE(x) BF64_DECODE(x, 63, 1)
120 #define SM_DEBUG_ENCODE(x) BF64_ENCODE(x, 63, 1)
121
122 #define SM_DEBUG_ACTION_DECODE(x) BF64_DECODE(x, 60, 3)
123 #define SM_DEBUG_ACTION_ENCODE(x) BF64_ENCODE(x, 60, 3)
124
125 #define SM_DEBUG_SYNCPASS_DECODE(x) BF64_DECODE(x, 50, 10)
126 #define SM_DEBUG_SYNCPASS_ENCODE(x) BF64_ENCODE(x, 50, 10)
127
128 #define SM_DEBUG_TXG_DECODE(x) BF64_DECODE(x, 0, 50)
129 #define SM_DEBUG_TXG_ENCODE(x) BF64_ENCODE(x, 0, 50)
130
131 #define SM_RUN_MAX SM_RUN_DECODE(~0ULL)
132
133 typedef enum {
134 SM_ALLOC,
135 SM_FREE
136 } maptype_t;
137
138 /*
139 * The data for a given space map can be kept on blocks of any size.
140 * Larger blocks entail fewer i/o operations, but they also cause the
141 * DMU to keep more data in-core, and also to waste more i/o bandwidth
142 * when only a few blocks have changed since the last transaction group.
143 * Rather than having a fixed block size for all space maps the block size
144 * can adjust as needed (see space_map_max_blksz). Set the initial block
145 * size for the space map to 4k.
146 */
147 #define SPACE_MAP_INITIAL_BLOCKSIZE (1ULL << 12)
148
149 int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
150
151 void space_map_histogram_clear(space_map_t *sm);
152 void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
153 dmu_tx_t *tx);
154
155 void space_map_update(space_map_t *sm);
156
157 uint64_t space_map_object(space_map_t *sm);
158 uint64_t space_map_allocated(space_map_t *sm);
159 uint64_t space_map_length(space_map_t *sm);
160
161 void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
162 dmu_tx_t *tx);
163 void space_map_truncate(space_map_t *sm, dmu_tx_t *tx);
164 uint64_t space_map_alloc(objset_t *os, dmu_tx_t *tx);
165 void space_map_free(space_map_t *sm, dmu_tx_t *tx);
166
167 int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
168 uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp);
169 void space_map_close(space_map_t *sm);
170
171 int64_t space_map_alloc_delta(space_map_t *sm);
172
173 #ifdef __cplusplus
174 }
175 #endif
176
177 #endif /* _SYS_SPACE_MAP_H */