FreeBSD/Linux Kernel Cross Reference
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. 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: releng/5.1/sys/vm/swap_pager.h 113956 2003-04-24 05:29:27Z alc $
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 */
53 struct 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
91 struct 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
99 extern struct pagerlst swap_pager_un_object_list;
100 extern int swap_pager_full;
101 extern struct blist *swapblist;
102 extern struct uma_zone *swap_zone;
103 extern int nswap_lowat, nswap_hiwat;
104 extern int dmmax, dmmax_mask;
105 extern struct vnode *swapdev_vp;
106 extern struct swdevt *swdevt;
107 extern 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 */
112 extern int vm_swap_size; /* number of free swap blocks, in pages */
113
114 void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
115 boolean_t swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after);
116 void swap_pager_swapoff(int devidx, int *sw_used);
117
118 int swap_pager_swp_alloc(vm_object_t, int);
119 void swap_pager_copy(vm_object_t, vm_object_t, vm_pindex_t, int);
120 void swap_pager_freespace(vm_object_t, vm_pindex_t, vm_size_t);
121 void swap_pager_dmzspace(vm_object_t, vm_pindex_t, vm_size_t);
122 void swap_pager_swap_init(void);
123 int swap_pager_isswapped(vm_object_t, int);
124 int swap_pager_reserve(vm_object_t, vm_pindex_t, vm_size_t);
125
126 /*
127 * newswap functions
128 */
129
130 void swap_pager_page_removed(vm_page_t, vm_object_t);
131
132 #endif /* _KERNEL */
133 #endif /* _VM_SWAP_PAGER_H_ */
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