proc->thread stage 4: rework the VFS and DEVICE subsystems to take thread
[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 $
1de703da 40 * $DragonFly: src/sys/vm/swap_pager.h,v 1.2 2003/06/17 04:29:00 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
48#ifndef _SWAP_PAGER_
49#define _SWAP_PAGER_ 1
50
51/*
52 * SWB_NPAGES must be a power of 2. It may be set to 1, 2, 4, 8, or 16
53 * pages per allocation. We recommend you stick with the default of 8.
54 * The 16-page limit is due to the radix code (kern/subr_blist.c).
55 */
56#if !defined(SWB_NPAGES)
57#define SWB_NPAGES 8
58#endif
59
60/*
61 * Piecemeal swap metadata structure. Swap is stored in a radix tree.
62 *
63 * If SWB_NPAGES is 8 and sizeof(char *) == sizeof(daddr_t), our radix
64 * is basically 8. Assuming PAGE_SIZE == 4096, one tree level represents
65 * 32K worth of data, two levels represent 256K, three levels represent
66 * 2 MBytes. This is acceptable.
67 *
68 * Overall memory utilization is about the same as the old swap structure.
69 */
70
71#define SWCORRECT(n) (sizeof(void *) * (n) / sizeof(daddr_t))
72
73#define SWAP_META_PAGES (SWB_NPAGES * 2)
74#define SWAP_META_MASK (SWAP_META_PAGES - 1)
75
76struct swblock {
77 struct swblock *swb_hnext;
78 vm_object_t swb_object;
79 vm_pindex_t swb_index;
80 int swb_count;
81 daddr_t swb_pages[SWAP_META_PAGES];
82};
83
84#ifdef _KERNEL
85extern struct pagerlst swap_pager_un_object_list;
86extern int swap_pager_full;
87extern struct blist *swapblist;
88
89void swap_pager_putpages __P((vm_object_t, vm_page_t *, int, boolean_t, int *));
90boolean_t swap_pager_haspage __P((vm_object_t object, vm_pindex_t pindex, int *before, int *after));
91
92int swap_pager_swp_alloc __P((vm_object_t, int));
93void swap_pager_copy __P((vm_object_t, vm_object_t, vm_pindex_t, int));
94void swap_pager_freespace __P((vm_object_t, vm_pindex_t, vm_size_t));
95void swap_pager_dmzspace __P((vm_object_t, vm_pindex_t, vm_size_t));
96void swap_pager_swap_init __P((void));
97int swap_pager_reserve __P((vm_object_t, vm_pindex_t, vm_size_t));
98
99/*
100 * newswap functions
101 */
102
103void swap_pager_page_removed __P((vm_page_t, vm_object_t));
104
105/* choose underlying swap device and queue up I/O */
106struct buf;
107void swstrategy __P((struct buf *bp)); /* probably needs to move elsewhere */
108
109#endif
110
111#endif /* _SWAP_PAGER_ */