swap_pager.h revision 108602 
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: head/sys/vm/swap_pager.h 108602 2003-01-03 16:23:12Z phk $
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_ 1
49
50/*
51 * Swap device table
52 */
53struct swdevt {
54	udev_t	sw_dev;			/* For quasibogus swapdev reporting */
55	int	sw_flags;
56	int	sw_nblks;
57	int     sw_used;
58	struct	vnode *sw_vp;
59	dev_t	sw_device;
60};
61#define	SW_FREED	0x01
62#define	SW_SEQUENTIAL	0x02
63#define	SW_CLOSING	0x04
64#define	sw_freed	sw_flags	/* XXX compat */
65
66#ifdef _KERNEL
67
68/*
69 * SWB_NPAGES must be a power of 2.  It may be set to 1, 2, 4, 8, or 16
70 * pages per allocation.  We recommend you stick with the default of 8.
71 * The 16-page limit is due to the radix code (kern/subr_blist.c).
72 */
73#if !defined(SWB_NPAGES)
74#define SWB_NPAGES 8
75#endif
76
77/*
78 * Piecemeal swap metadata structure.  Swap is stored in a radix tree.
79 *
80 * If SWB_NPAGES is 8 and sizeof(char *) == sizeof(daddr_t), our radix
81 * is basically 8.  Assuming PAGE_SIZE == 4096, one tree level represents
82 * 32K worth of data, two levels represent 256K, three levels represent
83 * 2 MBytes.   This is acceptable.
84 *
85 * Overall memory utilization is about the same as the old swap structure.
86 */
87#define SWCORRECT(n) (sizeof(void *) * (n) / sizeof(daddr_t))
88#define SWAP_META_PAGES		(SWB_NPAGES * 2)
89#define SWAP_META_MASK		(SWAP_META_PAGES - 1)
90
91struct swblock {
92	struct swblock	*swb_hnext;
93	vm_object_t	swb_object;
94	vm_pindex_t	swb_index;
95	int		swb_count;
96	daddr_t		swb_pages[SWAP_META_PAGES];
97};
98
99extern struct pagerlst swap_pager_un_object_list;
100extern int swap_pager_full;
101extern struct blist *swapblist;
102extern struct uma_zone *swap_zone;
103extern int nswap_lowat, nswap_hiwat;
104extern int dmmax, dmmax_mask;
105extern struct vnode *swapdev_vp;
106extern struct swdevt *swdevt;
107extern int nswdev;
108/*
109 * vm_swap_size is in page-sized chunks now.  It was DEV_BSIZE'd chunks
110 * in the old system.
111 */
112extern int vm_swap_size;	/* number of free swap blocks, in pages */
113
114void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
115boolean_t swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after);
116void swap_pager_swapoff(int devidx, int *sw_used);
117
118int swap_pager_swp_alloc(vm_object_t, int);
119void swap_pager_copy(vm_object_t, vm_object_t, vm_pindex_t, int);
120void swap_pager_freespace(vm_object_t, vm_pindex_t, vm_size_t);
121void swap_pager_dmzspace(vm_object_t, vm_pindex_t, vm_size_t);
122void swap_pager_swap_init(void);
123int swap_pager_reserve(vm_object_t, vm_pindex_t, vm_size_t);
124
125/*
126 * newswap functions
127 */
128
129void swap_pager_page_removed(vm_page_t, vm_object_t);
130
131/* choose underlying swap device and queue up I/O */
132struct buf;
133void swstrategy(struct buf *bp);	/* probably needs to move elsewhere */
134
135#endif				/* _KERNEL */
136#endif				/* _VM_SWAP_PAGER_H_ */
137