sys/vm/swap_pager.h

   1 /*
   2  * Copyright (c) 1990 University of Utah.
   3  * Copyright (c) 1991 The Regents of the University of California.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * the Systems Programming Group of the University of Utah Computer
   8  * Science Department.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      from: @(#)swap_pager.h  7.1 (Berkeley) 12/5/90
  39  * $FreeBSD: src/sys/vm/swap_pager.h,v 1.28.2.1 2000/10/13 07:13:23 dillon Exp $
  40  */
  41
  42 /*
  43  * Modifications to the block allocation data structure by John S. Dyson
  44  * 18 Dec 93.
  45  */
  46
  47 #ifndef _VM_SWAP_PAGER_H_
  48 #define _VM_SWAP_PAGER_H_
  49
  50 #ifndef _SYS_TYPES_H_
  51 #include <sys/types.h>
  52 #endif
  53 #ifndef _VM_VM_OBJECT_H_
  54 #include <vm/vm_object.h>
  55 #endif
  56 #ifndef _SYS_BLIST_H_
  57 #include <sys/blist.h>
  58 #endif
  59
  60 /*
  61  * SWB_NPAGES must be a power of 2.  It may be set to 1, 2, 4, 8, or 16
  62  * pages per allocation.  We recommend you stick with the default of 8.
  63  * The 16-page limit is due to the radix code (kern/subr_blist.c).
  64  */
  65 #define SWB_NPAGES      16
  66
  67 /*
  68  * Piecemeal swap metadata structure.  Swap is stored in a hash table.
  69  *
  70  * Storage use is ~1:16384 or so.
  71  *
  72  * Overall memory utilization is about the same as the old swap structure.
  73  */
  74
  75 #define SWAP_META_PAGES         (SWB_NPAGES * 2)
  76 #define SWAP_META_MASK          (SWAP_META_PAGES - 1)
  77
  78 struct swblock {
  79         RB_ENTRY(swblock) swb_entry;
  80         vm_pindex_t     swb_index;
  81         int             swb_count;
  82         swblk_t         swb_pages[SWAP_META_PAGES];
  83 };
  84
  85 #ifdef _KERNEL
  86 extern int swap_pager_full;
  87 extern int swap_pager_almost_full;
  88 extern int swap_fail_ticks;
  89 extern int vm_swap_size;
  90 extern int vm_swap_max;
  91 extern int vm_swap_cache_use;
  92 extern int vm_swap_anon_use;
  93 extern int vm_swapcache_read_enable;
  94 extern int vm_swapcache_inactive_heuristic;
  95 extern int vm_swapcache_use_chflags;
  96
  97 extern struct blist *swapblist;
  98 extern int nswap_lowat, nswap_hiwat;
  99
 100 void swap_pager_putpages (vm_object_t, struct vm_page **, int, int, int *);
 101 boolean_t swap_pager_haspage (vm_object_t object, vm_pindex_t pindex);
 102 int swap_pager_swapoff (int devidx);
 103
 104 int swap_pager_swp_alloc (vm_object_t, int);
 105 void swap_pager_copy (vm_object_t, vm_object_t, vm_pindex_t, int);
 106 void swap_pager_freespace (vm_object_t, vm_pindex_t, vm_pindex_t);
 107 void swap_pager_freespace_all (vm_object_t);
 108 int swap_pager_condfree(vm_object_t, vm_pindex_t *, int);
 109
 110 void swap_pager_page_inserted(vm_page_t);
 111 void swap_pager_swap_init (void);
 112 void swap_pager_newswap (void);
 113 int swap_pager_reserve (vm_object_t, vm_pindex_t, vm_size_t);
 114
 115 void swapacctspace(swblk_t base, swblk_t count);
 116
 117 /*
 118  * newswap functions
 119  */
 120
 121 void swap_pager_page_removed (struct vm_page *, vm_object_t);
 122
 123 /* choose underlying swap device and queue up I/O */
 124 struct buf;
 125 void swstrategy (struct buf *bp);       /* probably needs to move elsewhere */
 126
 127 #endif
 128
 129 #endif                          /* _VM_SWAP_PAGER_H_ */