arc.h revision 288594
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, 2014 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
33extern "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
46typedef struct arc_buf_hdr arc_buf_hdr_t;
47typedef struct arc_buf arc_buf_t;
48typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *priv);
49typedef int arc_evict_func_t(void *priv);
50
51/* generic arc_done_func_t's which you can use */
52arc_done_func_t arc_bcopy_func;
53arc_done_func_t arc_getbuf_func;
54
55typedef enum arc_flags
56{
57	/*
58	 * Public flags that can be passed into the ARC by external consumers.
59	 */
60	ARC_FLAG_NONE			= 1 << 0,	/* No flags set */
61	ARC_FLAG_WAIT			= 1 << 1,	/* perform sync I/O */
62	ARC_FLAG_NOWAIT			= 1 << 2,	/* perform async I/O */
63	ARC_FLAG_PREFETCH		= 1 << 3,	/* I/O is a prefetch */
64	ARC_FLAG_CACHED			= 1 << 4,	/* I/O was in cache */
65	ARC_FLAG_L2CACHE		= 1 << 5,	/* cache in L2ARC */
66	ARC_FLAG_L2COMPRESS		= 1 << 6,	/* compress in L2ARC */
67	ARC_FLAG_PREDICTIVE_PREFETCH	= 1 << 7,	/* I/O from zfetch */
68
69	/*
70	 * Private ARC flags.  These flags are private ARC only flags that
71	 * will show up in b_flags in the arc_hdr_buf_t. These flags should
72	 * only be set by ARC code.
73	 */
74	ARC_FLAG_IN_HASH_TABLE		= 1 << 8,	/* buffer is hashed */
75	ARC_FLAG_IO_IN_PROGRESS		= 1 << 9,	/* I/O in progress */
76	ARC_FLAG_IO_ERROR		= 1 << 10,	/* I/O failed for buf */
77	ARC_FLAG_FREED_IN_READ		= 1 << 11,	/* freed during read */
78	ARC_FLAG_BUF_AVAILABLE		= 1 << 12,	/* block not in use */
79	ARC_FLAG_INDIRECT		= 1 << 13,	/* indirect block */
80	/* Indicates that block was read with ASYNC priority. */
81	ARC_FLAG_PRIO_ASYNC_READ	= 1 << 14,
82	ARC_FLAG_L2_WRITING		= 1 << 15,	/* write in progress */
83	ARC_FLAG_L2_EVICTED		= 1 << 16,	/* evicted during I/O */
84	ARC_FLAG_L2_WRITE_HEAD		= 1 << 17,	/* head of write list */
85	/* indicates that the buffer contains metadata (otherwise, data) */
86	ARC_FLAG_BUFC_METADATA		= 1 << 18,
87
88	/* Flags specifying whether optional hdr struct fields are defined */
89	ARC_FLAG_HAS_L1HDR		= 1 << 19,
90	ARC_FLAG_HAS_L2HDR		= 1 << 20,
91
92
93	/*
94	 * The arc buffer's compression mode is stored in the top 7 bits of the
95	 * flags field, so these dummy flags are included so that MDB can
96	 * interpret the enum properly.
97	 */
98	ARC_FLAG_COMPRESS_0		= 1 << 24,
99	ARC_FLAG_COMPRESS_1		= 1 << 25,
100	ARC_FLAG_COMPRESS_2		= 1 << 26,
101	ARC_FLAG_COMPRESS_3		= 1 << 27,
102	ARC_FLAG_COMPRESS_4		= 1 << 28,
103	ARC_FLAG_COMPRESS_5		= 1 << 29,
104	ARC_FLAG_COMPRESS_6		= 1 << 30
105
106} arc_flags_t;
107
108struct arc_buf {
109	arc_buf_hdr_t		*b_hdr;
110	arc_buf_t		*b_next;
111	kmutex_t		b_evict_lock;
112	void			*b_data;
113	arc_evict_func_t	*b_efunc;
114	void			*b_private;
115};
116
117typedef enum arc_buf_contents {
118	ARC_BUFC_DATA,				/* buffer contains data */
119	ARC_BUFC_METADATA,			/* buffer contains metadata */
120	ARC_BUFC_NUMTYPES
121} arc_buf_contents_t;
122
123/*
124 * The following breakdows of arc_size exist for kstat only.
125 */
126typedef enum arc_space_type {
127	ARC_SPACE_DATA,
128	ARC_SPACE_META,
129	ARC_SPACE_HDRS,
130	ARC_SPACE_L2HDRS,
131	ARC_SPACE_OTHER,
132	ARC_SPACE_NUMTYPES
133} arc_space_type_t;
134
135void arc_space_consume(uint64_t space, arc_space_type_t type);
136void arc_space_return(uint64_t space, arc_space_type_t type);
137arc_buf_t *arc_buf_alloc(spa_t *spa, int size, void *tag,
138    arc_buf_contents_t type);
139arc_buf_t *arc_loan_buf(spa_t *spa, int size);
140void arc_return_buf(arc_buf_t *buf, void *tag);
141void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
142void arc_buf_add_ref(arc_buf_t *buf, void *tag);
143boolean_t arc_buf_remove_ref(arc_buf_t *buf, void *tag);
144int arc_buf_size(arc_buf_t *buf);
145void arc_release(arc_buf_t *buf, void *tag);
146int arc_released(arc_buf_t *buf);
147void arc_buf_freeze(arc_buf_t *buf);
148void arc_buf_thaw(arc_buf_t *buf);
149boolean_t arc_buf_eviction_needed(arc_buf_t *buf);
150#ifdef ZFS_DEBUG
151int arc_referenced(arc_buf_t *buf);
152#endif
153
154int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
155    arc_done_func_t *done, void *priv, zio_priority_t priority, int flags,
156    arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
157zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
158    blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
159    const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *physdone,
160    arc_done_func_t *done, void *priv, zio_priority_t priority,
161    int zio_flags, const zbookmark_phys_t *zb);
162void arc_freed(spa_t *spa, const blkptr_t *bp);
163
164void arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *priv);
165boolean_t arc_clear_callback(arc_buf_t *buf);
166
167void arc_flush(spa_t *spa, boolean_t retry);
168void arc_tempreserve_clear(uint64_t reserve);
169int arc_tempreserve_space(uint64_t reserve, uint64_t txg);
170
171void arc_init(void);
172void arc_fini(void);
173
174/*
175 * Level 2 ARC
176 */
177
178void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
179void l2arc_remove_vdev(vdev_t *vd);
180boolean_t l2arc_vdev_present(vdev_t *vd);
181void l2arc_init(void);
182void l2arc_fini(void);
183void l2arc_start(void);
184void l2arc_stop(void);
185
186#ifdef illumos
187#ifndef _KERNEL
188extern boolean_t arc_watch;
189extern int arc_procfd;
190#endif
191#endif /* illumos */
192
193#ifdef	__cplusplus
194}
195#endif
196
197#endif /* _SYS_ARC_H */
198