bsd/vm/vnode_pager.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * Mach Operating System
  32  * Copyright (c) 1987 Carnegie-Mellon University
  33  * All rights reserved.  The CMU software License Agreement specifies
  34  * the terms and conditions for use and redistribution.
  35  */
  36
  37 #ifndef _VNODE_PAGER_
  38 #define _VNODE_PAGER_   1
  39
  40 #include <mach/kern_return.h>
  41 #include <sys/types.h>
  42 #include <kern/queue.h>
  43
  44 #ifdef  KERNEL
  45 #include <mach/boolean.h>
  46 #include <mach/memory_object_types.h>
  47 #include <mach/vm_types.h>
  48 #include <vm/vm_pager.h>
  49
  50 vm_pager_t      vnode_pager_setup(struct vnode *, memory_object_t);
  51
  52 /*
  53  *  Vstructs are the internal (to us) description of a unit of backing store.
  54  *  The are the link between memory objects and the backing store they represent.
  55  *  For the vnode pager, backing store comes in two flavors: normal files and
  56  *  swap files.
  57  *
  58  *  For objects that page to and from normal files (e.g. objects that represent
  59  *  program text segments), we maintain some simple parameters that allow us to
  60  *  access the file's contents directly through the vnode interface.
  61  *
  62  *  Data for objects without associated vnodes is maintained in the swap files.
  63  *  Each object that uses one of these as backing store has a vstruct indicating
  64  *  the swap file of preference (vs_pf) and a mapping between contiguous object
  65  *  offsets and swap file offsets (vs_pmap).  Each entry in this mapping specifies
  66  *  the pager file to use, and the offset of the page in that pager file.  These
  67  *  mapping entries are of type pfMapEntry.
  68  */
  69
  70 /*
  71  * Pager file structure.  One per swap file.
  72  */
  73 typedef struct pager_file {
  74         queue_chain_t   pf_chain;       /* link to other paging files */
  75         struct  vnode   *pf_vp;         /* vnode of paging file */
  76         u_int           pf_count;       /* Number of vstruct using this file */
  77         u_char          *pf_bmap;       /* Map of used blocks */
  78         long            pf_npgs;        /* Size of file in pages */
  79         long            pf_pfree;       /* Number of unused pages */
  80         long            pf_lowat;       /* Low water page */
  81         long            pf_hipage;      /* Highest page allocated */
  82         long            pf_hint;        /* Lowest page unallocated */
  83         char            *pf_name;       /* Filename of this file */
  84         boolean_t       pf_prefer;
  85         int             pf_index;       /* index into the pager_file array */
  86         void *          pf_lock;        /* Lock for alloc and dealloc */
  87 } *pager_file_t;
  88
  89 #define PAGER_FILE_NULL (pager_file_t) 0
  90
  91 #define MAXPAGERFILES 16
  92
  93 #define MAX_BACKING_STORE 100
  94
  95 struct bs_map {
  96         struct vnode    *vp;
  97         void            *bs;
  98 };
  99 extern struct bs_map  bs_port_table[];
 100
 101
 102
 103 /*
 104  * Pager file data structures.
 105  */
 106 #define INDEX_NULL      0
 107 typedef struct {
 108         unsigned int index:8;   /* paging file this block is in */
 109         unsigned int offset:24; /* page number where block resides */
 110 } pf_entry;
 111
 112 typedef enum {
 113                 IS_INODE,       /* Local disk */
 114                 IS_RNODE        /* NFS */
 115         } vpager_fstype;
 116
 117 /*
 118  *  Basic vnode pager structure.  One per object, backing-store pair.
 119  */
 120 typedef struct vstruct {
 121         boolean_t       is_device;      /* Must be first - see vm_pager.h */
 122         pager_file_t    vs_pf;          /* Pager file this uses */
 123         pf_entry        **vs_pmap;      /* Map of pages into paging file */
 124         unsigned int
 125         /* boolean_t */ vs_swapfile:1;  /* vnode is a swapfile */
 126         short           vs_count;       /* use count */
 127         int             vs_size;        /* size of this chunk in pages*/
 128         struct vnode    *vs_vp;         /* vnode to page to */
 129 } *vnode_pager_t;
 130
 131 #define VNODE_PAGER_NULL        ((vnode_pager_t) 0)
 132
 133
 134 pager_return_t  vnode_pagein(struct vnode *, upl_t,
 135                              upl_offset_t, vm_object_offset_t,
 136                              upl_size_t, int, int *);
 137 pager_return_t  vnode_pageout(struct vnode *, upl_t,
 138                               upl_offset_t, vm_object_offset_t,
 139                               upl_size_t, int, int *);
 140
 141 extern vm_object_offset_t vnode_pager_get_filesize(
 142         struct vnode *vp);
 143
 144 extern kern_return_t vnode_pager_get_pathname(
 145         struct vnode    *vp,
 146         char            *pathname,
 147         vm_size_t       *length_p);
 148
 149 extern kern_return_t vnode_pager_get_filename(
 150         struct vnode    *vp,
 151         char            **filename);
 152
 153 #endif  /* KERNEL */
 154
 155 #endif  /* _VNODE_PAGER_ */