2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991 The Regents of the University of California.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
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 $
39 * Modifications to the block allocation data structure by John S. Dyson
43 #ifndef _VM_SWAP_PAGER_H_
44 #define _VM_SWAP_PAGER_H_
47 #include <sys/types.h>
49 #ifndef _VM_VM_OBJECT_H_
50 #include <vm/vm_object.h>
53 #include <sys/blist.h>
57 * SWB_NPAGES must be a power of 2. Note that DMMAX may not exceed
58 * SWBLK_BITS, so the limit for SWB_NPAGES is (SWBLK_BITS / 2).
63 * DMMAX is the stripe size and must be a power of 2 >= SWBLK_BITS to ensure
64 * that the blist code does not allocate a contiguous range that crosses a
67 #define SWB_DMMAX SWBLK_BITS
68 #define SWB_DMMASK (SWB_DMMAX - 1)
71 * Piecemeal swap metadata structure. Swap is stored in a RBTREE. Swap
72 * blocks are page-sized. e.g. block 1 is offset +4096 from block 0.
74 * ram:swap is around 1:341
76 * Overall memory utilization is about the same as the old swap structure.
79 #define SWAP_META_PAGES (SWB_NPAGES * 2)
80 #define SWAP_META_MASK (SWAP_META_PAGES - 1)
83 RB_ENTRY(swblock
) swb_entry
;
84 vm_pindex_t swb_index
;
86 swblk_t swb_pages
[SWAP_META_PAGES
];
90 extern int swap_pager_full
;
91 extern int swap_pager_almost_full
;
92 extern int swap_fail_ticks
;
93 extern int swap_user_async
;
94 extern swblk_t vm_swap_size
;
95 extern swblk_t vm_swap_max
;
96 extern swblk_t vm_swap_cache_use
;
97 extern swblk_t vm_swap_anon_use
;
98 extern int vm_swapcache_read_enable
;
99 extern int vm_swapcache_inactive_heuristic
;
100 extern int vm_swapcache_use_chflags
;
102 extern struct blist
*swapblist
;
103 extern int nswap_lowat
, nswap_hiwat
;
105 void swap_pager_putpages (vm_object_t
, struct vm_page
**, int, int, int *);
106 boolean_t
swap_pager_haspage (vm_object_t object
, vm_pindex_t pindex
);
107 int swap_pager_swapoff (int devidx
);
109 int swap_pager_swp_alloc (vm_object_t
, int);
110 void swap_pager_copy (vm_object_t
, vm_object_t
, vm_pindex_t
, int);
111 void swap_pager_freespace (vm_object_t
, vm_pindex_t
, vm_pindex_t
);
112 void swap_pager_freespace_all (vm_object_t
);
113 int swap_pager_condfree(vm_object_t
, vm_pindex_t
*, int);
115 void swap_pager_page_inserted(vm_page_t
);
116 void swap_pager_swap_init (void);
117 void swap_pager_newswap (void);
118 int swap_pager_reserve (vm_object_t
, vm_pindex_t
, vm_size_t
);
120 void swapacctspace(swblk_t base
, swblk_t count
);
126 void swap_pager_page_removed (struct vm_page
*, vm_object_t
);
128 /* choose underlying swap device and queue up I/O */
130 void swstrategy (struct buf
*bp
); /* probably needs to move elsewhere */
134 #endif /* _VM_SWAP_PAGER_H_ */