xref: /freebsd/sys/contrib/openzfs/include/sys/dmu_zfetch.h (revision 350b7c3570aa6c87c537e54f706f1866f93a4142)
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 https://opensource.org/licenses/CDDL-1.0.
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) 2014, 2017 by Delphix. All rights reserved.
28  */
29 
30 #ifndef	_DMU_ZFETCH_H
31 #define	_DMU_ZFETCH_H
32 
33 #include <sys/zfs_context.h>
34 
35 #ifdef	__cplusplus
36 extern "C" {
37 #endif
38 
39 extern uint64_t	zfetch_array_rd_sz;
40 
41 struct dnode;				/* so we can reference dnode */
42 
43 typedef struct zfetch {
44 	kmutex_t	zf_lock;	/* protects zfetch structure */
45 	list_t		zf_stream;	/* list of zstream_t's */
46 	struct dnode	*zf_dnode;	/* dnode that owns this zfetch */
47 	int		zf_numstreams;	/* number of zstream_t's */
48 } zfetch_t;
49 
50 typedef struct zstream {
51 	uint64_t	zs_blkid;	/* expect next access at this blkid */
52 	unsigned int	zs_pf_dist;	/* data prefetch distance in bytes */
53 	unsigned int	zs_ipf_dist;	/* L1 prefetch distance in bytes */
54 	uint64_t	zs_pf_start;	/* first data block to prefetch */
55 	uint64_t	zs_pf_end;	/* data block to prefetch up to */
56 	uint64_t	zs_ipf_start;	/* first data block to prefetch L1 */
57 	uint64_t	zs_ipf_end;	/* data block to prefetch L1 up to */
58 
59 	list_node_t	zs_node;	/* link for zf_stream */
60 	hrtime_t	zs_atime;	/* time last prefetch issued */
61 	zfetch_t	*zs_fetch;	/* parent fetch */
62 	boolean_t	zs_missed;	/* stream saw cache misses */
63 	boolean_t	zs_more;	/* need more distant prefetch */
64 	zfs_refcount_t	zs_callers;	/* number of pending callers */
65 	/*
66 	 * Number of stream references: dnode, callers and pending blocks.
67 	 * The stream memory is freed when the number returns to zero.
68 	 */
69 	zfs_refcount_t	zs_refs;
70 } zstream_t;
71 
72 void		zfetch_init(void);
73 void		zfetch_fini(void);
74 
75 void		dmu_zfetch_init(zfetch_t *, struct dnode *);
76 void		dmu_zfetch_fini(zfetch_t *);
77 zstream_t	*dmu_zfetch_prepare(zfetch_t *, uint64_t, uint64_t, boolean_t,
78     boolean_t);
79 void		dmu_zfetch_run(zstream_t *, boolean_t, boolean_t);
80 void		dmu_zfetch(zfetch_t *, uint64_t, uint64_t, boolean_t, boolean_t,
81     boolean_t);
82 
83 
84 #ifdef	__cplusplus
85 }
86 #endif
87 
88 #endif	/* _DMU_ZFETCH_H */
89