kernel - simplify vm pager ops, add pre-faulting for zero-fill pages.
[dragonfly.git] / sys / vm / swap_pager.h
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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 $
35d5bbd3 40 * $DragonFly: src/sys/vm/swap_pager.h,v 1.6 2008/08/10 22:09:52 dillon Exp $
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41 */
42
43/*
44 * Modifications to the block allocation data structure by John S. Dyson
45 * 18 Dec 93.
46 */
47
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48#ifndef _VM_SWAP_PAGER_H_
49#define _VM_SWAP_PAGER_H_
50
51#ifndef _SYS_TYPES_H_
52#include <sys/types.h>
53#endif
54#ifndef _VM_VM_OBJECT_H_
55#include <vm/vm_object.h>
56#endif
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57#ifndef _SYS_BLIST_H_
58#include <sys/blist.h>
59#endif
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60
61/*
62 * SWB_NPAGES must be a power of 2. It may be set to 1, 2, 4, 8, or 16
63 * pages per allocation. We recommend you stick with the default of 8.
64 * The 16-page limit is due to the radix code (kern/subr_blist.c).
65 */
66#if !defined(SWB_NPAGES)
67#define SWB_NPAGES 8
68#endif
69
70/*
35d5bbd3 71 * Piecemeal swap metadata structure. Swap is stored in a hash table.
984263bc 72 *
35d5bbd3 73 * Storage use is ~1:16384 or so.
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74 *
75 * Overall memory utilization is about the same as the old swap structure.
76 */
77
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78#define SWAP_META_PAGES (SWB_NPAGES * 2)
79#define SWAP_META_MASK (SWAP_META_PAGES - 1)
80
81struct swblock {
82 struct swblock *swb_hnext;
83 vm_object_t swb_object;
84 vm_pindex_t swb_index;
85 int swb_count;
35d5bbd3 86 swblk_t swb_pages[SWAP_META_PAGES];
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87};
88
89#ifdef _KERNEL
90extern struct pagerlst swap_pager_un_object_list;
91extern int swap_pager_full;
92extern struct blist *swapblist;
93
03d6a592 94void swap_pager_putpages (vm_object_t, struct vm_page **, int, boolean_t, int *);
1b9d3514 95boolean_t swap_pager_haspage (vm_object_t object, vm_pindex_t pindex);
984263bc 96
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97int swap_pager_swp_alloc (vm_object_t, int);
98void swap_pager_copy (vm_object_t, vm_object_t, vm_pindex_t, int);
99void swap_pager_freespace (vm_object_t, vm_pindex_t, vm_size_t);
100void swap_pager_dmzspace (vm_object_t, vm_pindex_t, vm_size_t);
101void swap_pager_swap_init (void);
c84c24da 102void swap_pager_newswap (void);
1388df65 103int swap_pager_reserve (vm_object_t, vm_pindex_t, vm_size_t);
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104
105/*
106 * newswap functions
107 */
108
03d6a592 109void swap_pager_page_removed (struct vm_page *, vm_object_t);
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110
111/* choose underlying swap device and queue up I/O */
112struct buf;
1388df65 113void swstrategy (struct buf *bp); /* probably needs to move elsewhere */
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114
115#endif
116
1bd40720 117#endif /* _VM_SWAP_PAGER_H_ */