dmu_zfetch.h revision 1.1.1.1 
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 2006 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#ifndef	_DFETCH_H
27#define	_DFETCH_H
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#include <sys/zfs_context.h>
32
33#ifdef	__cplusplus
34extern "C" {
35#endif
36
37extern uint64_t	zfetch_array_rd_sz;
38
39struct dnode;				/* so we can reference dnode */
40
41typedef enum zfetch_dirn {
42	ZFETCH_FORWARD = 1,		/* prefetch increasing block numbers */
43	ZFETCH_BACKWARD	= -1		/* prefetch decreasing block numbers */
44} zfetch_dirn_t;
45
46typedef struct zstream {
47	uint64_t	zst_offset;	/* offset of starting block in range */
48	uint64_t	zst_len;	/* length of range, in blocks */
49	zfetch_dirn_t	zst_direction;	/* direction of prefetch */
50	uint64_t	zst_stride;	/* length of stride, in blocks */
51	uint64_t	zst_ph_offset;	/* prefetch offset, in blocks */
52	uint64_t	zst_cap;	/* prefetch limit (cap), in blocks */
53	kmutex_t	zst_lock;	/* protects stream */
54	clock_t		zst_last;	/* lbolt of last prefetch */
55	avl_node_t	zst_node;	/* embed avl node here */
56} zstream_t;
57
58typedef struct zfetch {
59	krwlock_t	zf_rwlock;	/* protects zfetch structure */
60	list_t		zf_stream;	/* AVL tree of zstream_t's */
61	struct dnode	*zf_dnode;	/* dnode that owns this zfetch */
62	uint32_t	zf_stream_cnt;	/* # of active streams */
63	uint64_t	zf_alloc_fail;	/* # of failed attempts to alloc strm */
64} zfetch_t;
65
66void		dmu_zfetch_init(zfetch_t *, struct dnode *);
67void		dmu_zfetch_rele(zfetch_t *);
68void		dmu_zfetch(zfetch_t *, uint64_t, uint64_t, int);
69
70
71#ifdef	__cplusplus
72}
73#endif
74
75#endif	/* _DFETCH_H */
76