bsd/vm/vnode_pager.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1987 Carnegie-Mellon University
  28  * All rights reserved.  The CMU software License Agreement specifies
  29  * the terms and conditions for use and redistribution.
  30  */
  31
  32 #ifndef _VNODE_PAGER_
  33 #define _VNODE_PAGER_   1
  34
  35 #include <mach/kern_return.h>
  36 #include <sys/types.h>
  37 #include <kern/queue.h>
  38
  39 #ifdef  KERNEL
  40
  41 #include <mach/boolean.h>
  42 #include <vm/vm_pager.h>
  43
  44 vm_pager_t      vnode_pager_setup();
  45 boolean_t       vnode_has_page();
  46 boolean_t       vnode_pager_active();
  47
  48 /*
  49  *  Vstructs are the internal (to us) description of a unit of backing store.
  50  *  The are the link between memory objects and the backing store they represent.
  51  *  For the vnode pager, backing store comes in two flavors: normal files and
  52  *  swap files.
  53  *
  54  *  For objects that page to and from normal files (e.g. objects that represent
  55  *  program text segments), we maintain some simple parameters that allow us to
  56  *  access the file's contents directly through the vnode interface.
  57  *
  58  *  Data for objects without associated vnodes is maintained in the swap files.
  59  *  Each object that uses one of these as backing store has a vstruct indicating
  60  *  the swap file of preference (vs_pf) and a mapping between contiguous object
  61  *  offsets and swap file offsets (vs_pmap).  Each entry in this mapping specifies
  62  *  the pager file to use, and the offset of the page in that pager file.  These
  63  *  mapping entries are of type pfMapEntry.
  64  */
  65
  66 /*
  67  * Pager file structure.  One per swap file.
  68  */
  69 typedef struct pager_file {
  70         queue_chain_t   pf_chain;       /* link to other paging files */
  71         struct  vnode   *pf_vp;         /* vnode of paging file */
  72         u_int           pf_count;       /* Number of vstruct using this file */
  73         u_char          *pf_bmap;       /* Map of used blocks */
  74         long            pf_npgs;        /* Size of file in pages */
  75         long            pf_pfree;       /* Number of unused pages */
  76         long            pf_lowat;       /* Low water page */
  77         long            pf_hipage;      /* Highest page allocated */
  78         long            pf_hint;        /* Lowest page unallocated */
  79         char            *pf_name;       /* Filename of this file */
  80         boolean_t       pf_prefer;
  81         int             pf_index;       /* index into the pager_file array */
  82         void *          pf_lock;        /* Lock for alloc and dealloc */
  83 } *pager_file_t;
  84
  85 #define PAGER_FILE_NULL (pager_file_t) 0
  86
  87 #define MAXPAGERFILES 16
  88
  89 #define MAX_BACKING_STORE 100
  90
  91 struct bs_map {
  92         struct vnode    *vp;
  93         void            *bs;
  94 };
  95
  96
  97
  98 /*
  99  * Pager file data structures.
 100  */
 101 #define INDEX_NULL      0
 102 typedef struct {
 103         unsigned int index:8;   /* paging file this block is in */
 104         unsigned int offset:24; /* page number where block resides */
 105 } pf_entry;
 106
 107 typedef enum {
 108                 IS_INODE,       /* Local disk */
 109                 IS_RNODE        /* NFS */
 110         } vpager_fstype;
 111
 112 /*
 113  *  Basic vnode pager structure.  One per object, backing-store pair.
 114  */
 115 typedef struct vstruct {
 116         boolean_t       is_device;      /* Must be first - see vm_pager.h */
 117         pager_file_t    vs_pf;          /* Pager file this uses */
 118         pf_entry        **vs_pmap;      /* Map of pages into paging file */
 119         unsigned int
 120         /* boolean_t */ vs_swapfile:1;  /* vnode is a swapfile */
 121         short           vs_count;       /* use count */
 122         int             vs_size;        /* size of this chunk in pages*/
 123         struct vnode    *vs_vp;         /* vnode to page to */
 124 } *vnode_pager_t;
 125
 126 #define VNODE_PAGER_NULL        ((vnode_pager_t) 0)
 127
 128
 129
 130 pager_return_t  pager_vnode_pagein();
 131 pager_return_t  pager_vnode_pageout();
 132 pager_return_t  vnode_pagein();
 133 pager_return_t  vnode_pageout();
 134
 135 #endif  /* KERNEL */
 136
 137 #endif  /* _VNODE_PAGER_ */