FreeBSD/Linux Kernel Cross Reference
sys/bsd/vm/vnode_pager.h

     /*
      * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_LICENSE_HEADER_START@
      * 
      * The contents of this file constitute Original Code as defined in and
      * are subject to the Apple Public Source License Version 1.1 (the
      * "License").  You may not use this file except in compliance with the
      * License.  Please obtain a copy of the License at
     * http://www.apple.com/publicsource and read it before using this file.
     * 
     * This Original Code and all software distributed under the License are
     * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
     * License for the specific language governing rights and limitations
     * under the License.
     * 
     * @APPLE_LICENSE_HEADER_END@
     */
    /* 
     * Mach Operating System
     * Copyright (c) 1987 Carnegie-Mellon University
     * All rights reserved.  The CMU software License Agreement specifies
     * the terms and conditions for use and redistribution.
     */
    
    #ifndef _VNODE_PAGER_
    #define _VNODE_PAGER_   1
    
    #include <mach/kern_return.h>
    #include <sys/types.h>
    #include <kern/queue.h>
    
    #ifdef  KERNEL
    #include <mach/boolean.h>
    #include <mach/memory_object_types.h>
    #include <mach/vm_types.h>
    #include <vm/vm_pager.h>
    
    vm_pager_t      vnode_pager_setup(struct vnode *, memory_object_t);
    
    /*
     *  Vstructs are the internal (to us) description of a unit of backing store.
     *  The are the link between memory objects and the backing store they represent.
     *  For the vnode pager, backing store comes in two flavors: normal files and
     *  swap files.
     *
     *  For objects that page to and from normal files (e.g. objects that represent
     *  program text segments), we maintain some simple parameters that allow us to
     *  access the file's contents directly through the vnode interface.
     *
     *  Data for objects without associated vnodes is maintained in the swap files.
     *  Each object that uses one of these as backing store has a vstruct indicating
     *  the swap file of preference (vs_pf) and a mapping between contiguous object
     *  offsets and swap file offsets (vs_pmap).  Each entry in this mapping specifies
     *  the pager file to use, and the offset of the page in that pager file.  These
     *  mapping entries are of type pfMapEntry.
     */
    
    /*
     * Pager file structure.  One per swap file.
     */
    typedef struct pager_file {
            queue_chain_t   pf_chain;       /* link to other paging files */
            struct  vnode   *pf_vp;         /* vnode of paging file */
            u_int           pf_count;       /* Number of vstruct using this file */
            u_char          *pf_bmap;       /* Map of used blocks */
            long            pf_npgs;        /* Size of file in pages */
            long            pf_pfree;       /* Number of unused pages */
            long            pf_lowat;       /* Low water page */
            long            pf_hipage;      /* Highest page allocated */
            long            pf_hint;        /* Lowest page unallocated */
            char            *pf_name;       /* Filename of this file */
            boolean_t       pf_prefer;
            int             pf_index;       /* index into the pager_file array */
            void *          pf_lock;        /* Lock for alloc and dealloc */
    } *pager_file_t;
    
    #define PAGER_FILE_NULL (pager_file_t) 0
    
    #define MAXPAGERFILES 16
    
    #define MAX_BACKING_STORE 100
    
    struct bs_map {
            struct vnode    *vp;   
            void            *bs;
    };
    extern struct bs_map  bs_port_table[];
    
    
    
    /*
     * Pager file data structures.
     */
    #define INDEX_NULL      0
    typedef struct {
           unsigned int index:8;   /* paging file this block is in */
           unsigned int offset:24; /* page number where block resides */
   } pf_entry;
   
   typedef enum {
                   IS_INODE,       /* Local disk */
                   IS_RNODE        /* NFS */
           } vpager_fstype;
   
   /*
    *  Basic vnode pager structure.  One per object, backing-store pair.
    */
   typedef struct vstruct {
           boolean_t       is_device;      /* Must be first - see vm_pager.h */
           pager_file_t    vs_pf;          /* Pager file this uses */
           pf_entry        **vs_pmap;      /* Map of pages into paging file */
           unsigned int
           /* boolean_t */ vs_swapfile:1;  /* vnode is a swapfile */
           short           vs_count;       /* use count */
           int             vs_size;        /* size of this chunk in pages*/
           struct vnode    *vs_vp;         /* vnode to page to */
   } *vnode_pager_t;
   
   #define VNODE_PAGER_NULL        ((vnode_pager_t) 0)
   
   
   pager_return_t  vnode_pagein(struct vnode *, upl_t,
                                upl_offset_t, vm_object_offset_t,
                                upl_size_t, int, int *);
   pager_return_t  vnode_pageout(struct vnode *, upl_t,
                                 upl_offset_t, vm_object_offset_t,
                                 upl_size_t, int, int *);
   
   extern vm_object_offset_t vnode_pager_get_filesize(
           struct vnode *vp);
   
   #endif  /* KERNEL */
   
   #endif  /* _VNODE_PAGER_ */

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