xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/arc.h (revision 5602294fda888d923d57a78bafdaf48ae6223dea)
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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
24  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25  */
26 
27 #ifndef	_SYS_ARC_H
28 #define	_SYS_ARC_H
29 
30 #include <sys/zfs_context.h>
31 
32 #ifdef	__cplusplus
33 extern "C" {
34 #endif
35 
36 #include <sys/zio.h>
37 #include <sys/dmu.h>
38 #include <sys/spa.h>
39 
40 /*
41  * Used by arc_flush() to inform arc_evict_state() that it should evict
42  * all available buffers from the arc state being passed in.
43  */
44 #define	ARC_EVICT_ALL	-1ULL
45 
46 #define	HDR_SET_LSIZE(hdr, x) do { \
47 	ASSERT(IS_P2ALIGNED(x, 1U << SPA_MINBLOCKSHIFT)); \
48 	(hdr)->b_lsize = ((x) >> SPA_MINBLOCKSHIFT); \
49 _NOTE(CONSTCOND) } while (0)
50 
51 #define	HDR_SET_PSIZE(hdr, x) do { \
52 	ASSERT(IS_P2ALIGNED((x), 1U << SPA_MINBLOCKSHIFT)); \
53 	(hdr)->b_psize = ((x) >> SPA_MINBLOCKSHIFT); \
54 _NOTE(CONSTCOND) } while (0)
55 
56 #define	HDR_GET_LSIZE(hdr)	((hdr)->b_lsize << SPA_MINBLOCKSHIFT)
57 #define	HDR_GET_PSIZE(hdr)	((hdr)->b_psize << SPA_MINBLOCKSHIFT)
58 
59 typedef struct arc_buf_hdr arc_buf_hdr_t;
60 typedef struct arc_buf arc_buf_t;
61 typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);
62 
63 /* generic arc_done_func_t's which you can use */
64 arc_done_func_t arc_bcopy_func;
65 arc_done_func_t arc_getbuf_func;
66 
67 extern int zfs_arc_num_sublists_per_state;
68 
69 typedef enum arc_flags
70 {
71 	/*
72 	 * Public flags that can be passed into the ARC by external consumers.
73 	 */
74 	ARC_FLAG_WAIT			= 1 << 0,	/* perform sync I/O */
75 	ARC_FLAG_NOWAIT			= 1 << 1,	/* perform async I/O */
76 	ARC_FLAG_PREFETCH		= 1 << 2,	/* I/O is a prefetch */
77 	ARC_FLAG_CACHED			= 1 << 3,	/* I/O was in cache */
78 	ARC_FLAG_L2CACHE		= 1 << 4,	/* cache in L2ARC */
79 	ARC_FLAG_PREDICTIVE_PREFETCH	= 1 << 5,	/* I/O from zfetch */
80 
81 	/*
82 	 * Private ARC flags.  These flags are private ARC only flags that
83 	 * will show up in b_flags in the arc_hdr_buf_t. These flags should
84 	 * only be set by ARC code.
85 	 */
86 	ARC_FLAG_IN_HASH_TABLE		= 1 << 6,	/* buffer is hashed */
87 	ARC_FLAG_IO_IN_PROGRESS		= 1 << 7,	/* I/O in progress */
88 	ARC_FLAG_IO_ERROR		= 1 << 8,	/* I/O failed for buf */
89 	ARC_FLAG_INDIRECT		= 1 << 9,	/* indirect block */
90 	/* Indicates that block was read with ASYNC priority. */
91 	ARC_FLAG_PRIO_ASYNC_READ	= 1 << 10,
92 	ARC_FLAG_L2_WRITING		= 1 << 11,	/* write in progress */
93 	ARC_FLAG_L2_EVICTED		= 1 << 12,	/* evicted during I/O */
94 	ARC_FLAG_L2_WRITE_HEAD		= 1 << 13,	/* head of write list */
95 	/* indicates that the buffer contains metadata (otherwise, data) */
96 	ARC_FLAG_BUFC_METADATA		= 1 << 14,
97 
98 	/* Flags specifying whether optional hdr struct fields are defined */
99 	ARC_FLAG_HAS_L1HDR		= 1 << 15,
100 	ARC_FLAG_HAS_L2HDR		= 1 << 16,
101 
102 	/*
103 	 * Indicates the arc_buf_hdr_t's b_pdata matches the on-disk data.
104 	 * This allows the l2arc to use the blkptr's checksum to verify
105 	 * the data without having to store the checksum in the hdr.
106 	 */
107 	ARC_FLAG_COMPRESSED_ARC		= 1 << 17,
108 	ARC_FLAG_SHARED_DATA		= 1 << 18,
109 
110 	/*
111 	 * The arc buffer's compression mode is stored in the top 7 bits of the
112 	 * flags field, so these dummy flags are included so that MDB can
113 	 * interpret the enum properly.
114 	 */
115 	ARC_FLAG_COMPRESS_0		= 1 << 24,
116 	ARC_FLAG_COMPRESS_1		= 1 << 25,
117 	ARC_FLAG_COMPRESS_2		= 1 << 26,
118 	ARC_FLAG_COMPRESS_3		= 1 << 27,
119 	ARC_FLAG_COMPRESS_4		= 1 << 28,
120 	ARC_FLAG_COMPRESS_5		= 1 << 29,
121 	ARC_FLAG_COMPRESS_6		= 1 << 30
122 
123 } arc_flags_t;
124 
125 typedef enum arc_buf_flags {
126 	ARC_BUF_FLAG_SHARED		= 1 << 0,
127 	ARC_BUF_FLAG_COMPRESSED		= 1 << 1
128 } arc_buf_flags_t;
129 
130 struct arc_buf {
131 	arc_buf_hdr_t		*b_hdr;
132 	arc_buf_t		*b_next;
133 	kmutex_t		b_evict_lock;
134 	void			*b_data;
135 	arc_buf_flags_t		b_flags;
136 };
137 
138 typedef enum arc_buf_contents {
139 	ARC_BUFC_INVALID,			/* invalid type */
140 	ARC_BUFC_DATA,				/* buffer contains data */
141 	ARC_BUFC_METADATA,			/* buffer contains metadata */
142 	ARC_BUFC_NUMTYPES
143 } arc_buf_contents_t;
144 
145 /*
146  * The following breakdows of arc_size exist for kstat only.
147  */
148 typedef enum arc_space_type {
149 	ARC_SPACE_DATA,
150 	ARC_SPACE_META,
151 	ARC_SPACE_HDRS,
152 	ARC_SPACE_L2HDRS,
153 	ARC_SPACE_OTHER,
154 	ARC_SPACE_NUMTYPES
155 } arc_space_type_t;
156 
157 void arc_space_consume(uint64_t space, arc_space_type_t type);
158 void arc_space_return(uint64_t space, arc_space_type_t type);
159 boolean_t arc_is_metadata(arc_buf_t *buf);
160 enum zio_compress arc_get_compression(arc_buf_t *buf);
161 int arc_decompress(arc_buf_t *buf);
162 arc_buf_t *arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type,
163     int32_t size);
164 arc_buf_t *arc_alloc_compressed_buf(spa_t *spa, void *tag,
165     uint64_t psize, uint64_t lsize, enum zio_compress compression_type);
166 arc_buf_t *arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size);
167 arc_buf_t *arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
168     enum zio_compress compression_type);
169 void arc_return_buf(arc_buf_t *buf, void *tag);
170 void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
171 void arc_buf_destroy(arc_buf_t *buf, void *tag);
172 int arc_buf_size(arc_buf_t *buf);
173 int arc_buf_lsize(arc_buf_t *buf);
174 void arc_release(arc_buf_t *buf, void *tag);
175 int arc_released(arc_buf_t *buf);
176 void arc_buf_freeze(arc_buf_t *buf);
177 void arc_buf_thaw(arc_buf_t *buf);
178 #ifdef ZFS_DEBUG
179 int arc_referenced(arc_buf_t *buf);
180 #endif
181 
182 int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
183     arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
184     arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
185 zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
186     blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp,
187     arc_done_func_t *ready, arc_done_func_t *child_ready,
188     arc_done_func_t *physdone, arc_done_func_t *done,
189     void *private, zio_priority_t priority, int zio_flags,
190     const zbookmark_phys_t *zb);
191 void arc_freed(spa_t *spa, const blkptr_t *bp);
192 
193 void arc_flush(spa_t *spa, boolean_t retry);
194 void arc_tempreserve_clear(uint64_t reserve);
195 int arc_tempreserve_space(uint64_t reserve, uint64_t txg);
196 
197 uint64_t arc_max_bytes(void);
198 void arc_init(void);
199 void arc_fini(void);
200 
201 /*
202  * Level 2 ARC
203  */
204 
205 void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
206 void l2arc_remove_vdev(vdev_t *vd);
207 boolean_t l2arc_vdev_present(vdev_t *vd);
208 void l2arc_init(void);
209 void l2arc_fini(void);
210 void l2arc_start(void);
211 void l2arc_stop(void);
212 
213 #ifndef _KERNEL
214 extern boolean_t arc_watch;
215 extern int arc_procfd;
216 #endif
217 
218 #ifdef	__cplusplus
219 }
220 #endif
221 
222 #endif /* _SYS_ARC_H */
223