bsd/vm/vnode_pager.h

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