zfs/lib/libzcommon/include/sys/dmu_zfetch.h

   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 */