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      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	"@(#)dmu_zfetch.h	1.2	06/07/17 SMI"
     30 
     31 #include <sys/zfs_context.h>
     32 
     33 #ifdef	__cplusplus
     34 extern "C" {
     35 #endif
     36 
     37 extern uint64_t	zfetch_array_rd_sz;
     38 
     39 struct dnode;				/* so we can reference dnode */
     40 
     41 typedef enum zfetch_dirn {
     42 	ZFETCH_FORWARD = 1,		/* prefetch increasing block numbers */
     43 	ZFETCH_BACKWARD	= -1		/* prefetch decreasing block numbers */
     44 } zfetch_dirn_t;
     45 
     46 typedef 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 
     58 typedef 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 
     66 void		dmu_zfetch_init(zfetch_t *, struct dnode *);
     67 void		dmu_zfetch_rele(zfetch_t *);
     68 void		dmu_zfetch(zfetch_t *, uint64_t, uint64_t, int);
     69 
     70 
     71 #ifdef	__cplusplus
     72 }
     73 #endif
     74 
     75 #endif	/* _DFETCH_H */
     76