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. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      from: @(#)swap_pager.h  7.1 (Berkeley) 12/5/90
  35  * $FreeBSD: src/sys/vm/swap_pager.h,v 1.28.2.1 2000/10/13 07:13:23 dillon Exp $
  36  */
  37
  38 /*
  39  * Modifications to the block allocation data structure by John S. Dyson
  40  * 18 Dec 93.
  41  */
  42
  43 #ifndef _VM_SWAP_PAGER_H_
  44 #define _VM_SWAP_PAGER_H_
  45
  46 #ifndef _SYS_TYPES_H_
  47 #include <sys/types.h>
  48 #endif
  49 #ifndef _VM_VM_OBJECT_H_
  50 #include <vm/vm_object.h>
  51 #endif
  52 #ifndef _SYS_BLIST_H_
  53 #include <sys/blist.h>
  54 #endif
  55
  56 /*
  57  * SWB_NPAGES must be a power of 2.  It may be set to 1, 2, 4, 8, or 16
  58  * pages per allocation.  We recommend you stick with the default of 8.
  59  * The 16-page limit is due to the radix code (kern/subr_blist.c).
  60  */
  61 #define SWB_NPAGES      16
  62
  63 /*
  64  * Piecemeal swap metadata structure.  Swap is stored in a RBTREE.  Swap
  65  * blocks are page-sized.  e.g. block 1 is offset +4096 from block 0.
  66  *
  67  * ram:swap is around 1:341
  68  *
  69  * Overall memory utilization is about the same as the old swap structure.
  70  */
  71
  72 #define SWAP_META_PAGES         (SWB_NPAGES * 2)
  73 #define SWAP_META_MASK          (SWAP_META_PAGES - 1)
  74
  75 struct swblock {
  76         RB_ENTRY(swblock) swb_entry;
  77         vm_pindex_t     swb_index;
  78         int             swb_count;
  79         swblk_t         swb_pages[SWAP_META_PAGES];
  80 };
  81
  82 #ifdef _KERNEL
  83 extern int swap_pager_full;
  84 extern int swap_pager_almost_full;
  85 extern int swap_fail_ticks;
  86 extern int swap_user_async;
  87 extern swblk_t vm_swap_size;
  88 extern swblk_t vm_swap_max;
  89 extern swblk_t vm_swap_cache_use;
  90 extern swblk_t vm_swap_anon_use;
  91 extern int vm_swapcache_read_enable;
  92 extern int vm_swapcache_inactive_heuristic;
  93 extern int vm_swapcache_use_chflags;
  94
  95 extern struct blist *swapblist;
  96 extern int nswap_lowat, nswap_hiwat;
  97
  98 void swap_pager_putpages (vm_object_t, struct vm_page **, int, int, int *);
  99 boolean_t swap_pager_haspage (vm_object_t object, vm_pindex_t pindex);
 100 int swap_pager_swapoff (int devidx);
 101
 102 int swap_pager_swp_alloc (vm_object_t, int);
 103 void swap_pager_copy (vm_object_t, vm_object_t, vm_pindex_t, int);
 104 void swap_pager_freespace (vm_object_t, vm_pindex_t, vm_pindex_t);
 105 void swap_pager_freespace_all (vm_object_t);
 106 int swap_pager_condfree(vm_object_t, vm_pindex_t *, int);
 107
 108 void swap_pager_page_inserted(vm_page_t);
 109 void swap_pager_swap_init (void);
 110 void swap_pager_newswap (void);
 111 int swap_pager_reserve (vm_object_t, vm_pindex_t, vm_size_t);
 112
 113 void swapacctspace(swblk_t base, swblk_t count);
 114
 115 /*
 116  * newswap functions
 117  */
 118
 119 void swap_pager_page_removed (struct vm_page *, vm_object_t);
 120
 121 /* choose underlying swap device and queue up I/O */
 122 struct buf;
 123 void swstrategy (struct buf *bp);       /* probably needs to move elsewhere */
 124
 125 #endif
 126
 127 #endif                          /* _VM_SWAP_PAGER_H_ */