/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2014, 2017 by Delphix. All rights reserved.
 */

#ifndef	_DMU_ZFETCH_H
#define	_DMU_ZFETCH_H

#include <sys/zfs_context.h>

#ifdef	__cplusplus
extern "C" {
#endif

struct dnode;				/* so we can reference dnode */

typedef struct zfetch {
	kmutex_t	zf_lock;	/* protects zfetch structure */
	list_t		zf_stream;	/* list of zstream_t's */
	struct dnode	*zf_dnode;	/* dnode that owns this zfetch */
	int		zf_numstreams;	/* number of zstream_t's */
} zfetch_t;

typedef struct zsrange {
	uint16_t	start;
	uint16_t	end;
} zsrange_t;

#define	ZFETCH_RANGES	9		/* Fits zstream_t into 128 bytes */

typedef struct zstream {
	list_node_t	zs_node;	/* link for zf_stream */
	uint64_t	zs_blkid;	/* expect next access at this blkid */
	uint_t		zs_atime;	/* time last prefetch issued */
	zsrange_t	zs_ranges[ZFETCH_RANGES]; /* ranges from future */
	unsigned int	zs_pf_dist;	/* data prefetch distance in bytes */
	unsigned int	zs_ipf_dist;	/* L1 prefetch distance in bytes */
	uint64_t	zs_pf_start;	/* first data block to prefetch */
	uint64_t	zs_pf_end;	/* data block to prefetch up to */
	uint64_t	zs_ipf_start;	/* first data block to prefetch L1 */
	uint64_t	zs_ipf_end;	/* data block to prefetch L1 up to */
	boolean_t	zs_missed;	/* stream saw cache misses */
	boolean_t	zs_more;	/* need more distant prefetch */
	zfs_refcount_t	zs_callers;	/* number of pending callers */
	/*
	 * Number of stream references: dnode, callers and pending blocks.
	 * The stream memory is freed when the number returns to zero.
	 */
	zfs_refcount_t	zs_refs;
} zstream_t;

void		zfetch_init(void);
void		zfetch_fini(void);

void		dmu_zfetch_init(zfetch_t *, struct dnode *);
void		dmu_zfetch_fini(zfetch_t *);
zstream_t	*dmu_zfetch_prepare(zfetch_t *, uint64_t, uint64_t, boolean_t,
    boolean_t);
void		dmu_zfetch_run(zfetch_t *, zstream_t *, boolean_t, boolean_t);
void		dmu_zfetch(zfetch_t *, uint64_t, uint64_t, boolean_t, boolean_t,
    boolean_t);


#ifdef	__cplusplus
}
#endif

#endif	/* _DMU_ZFETCH_H */
