xref: /titanic_41/usr/src/uts/common/fs/zfs/sys/dmu_zfetch.h (revision 7cbf8b4321709b0e17bf7f2a0fb387730a1b03c1)
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 #ifndef	_DFETCH_H
27 #define	_DFETCH_H
28 
29 #include <sys/zfs_context.h>
30 
31 #ifdef	__cplusplus
32 extern "C" {
33 #endif
34 
35 extern uint64_t	zfetch_array_rd_sz;
36 
37 struct dnode;				/* so we can reference dnode */
38 
39 typedef enum zfetch_dirn {
40 	ZFETCH_FORWARD = 1,		/* prefetch increasing block numbers */
41 	ZFETCH_BACKWARD	= -1		/* prefetch decreasing block numbers */
42 } zfetch_dirn_t;
43 
44 typedef struct zstream {
45 	uint64_t	zst_offset;	/* offset of starting block in range */
46 	uint64_t	zst_len;	/* length of range, in blocks */
47 	zfetch_dirn_t	zst_direction;	/* direction of prefetch */
48 	uint64_t	zst_stride;	/* length of stride, in blocks */
49 	uint64_t	zst_ph_offset;	/* prefetch offset, in blocks */
50 	uint64_t	zst_cap;	/* prefetch limit (cap), in blocks */
51 	kmutex_t	zst_lock;	/* protects stream */
52 	clock_t		zst_last;	/* lbolt of last prefetch */
53 	avl_node_t	zst_node;	/* embed avl node here */
54 } zstream_t;
55 
56 typedef struct zfetch {
57 	krwlock_t	zf_rwlock;	/* protects zfetch structure */
58 	list_t		zf_stream;	/* AVL tree of zstream_t's */
59 	struct dnode	*zf_dnode;	/* dnode that owns this zfetch */
60 	uint32_t	zf_stream_cnt;	/* # of active streams */
61 	uint64_t	zf_alloc_fail;	/* # of failed attempts to alloc strm */
62 } zfetch_t;
63 
64 void		zfetch_init(void);
65 void		zfetch_fini(void);
66 
67 void		dmu_zfetch_init(zfetch_t *, struct dnode *);
68 void		dmu_zfetch_rele(zfetch_t *);
69 void		dmu_zfetch(zfetch_t *, uint64_t, uint64_t, int);
70 
71 
72 #ifdef	__cplusplus
73 }
74 #endif
75 
76 #endif	/* _DFETCH_H */
77