swap_pager.h revision 8416 
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 *	$Id: swap_pager.h,v 1.5 1995/02/02 09:08:09 davidg Exp $
40 */
41
42/*
43 * Modifications to the block allocation data structure by John S. Dyson
44 * 18 Dec 93.
45 */
46
47#ifndef	_SWAP_PAGER_
48#define	_SWAP_PAGER_	1
49
50/*
51 * SWB_NPAGES can be set to any value from 1 to 16 pages per allocation,
52 * however, due to the allocation spilling into non-swap pager backed memory,
53 * suggest keeping SWB_NPAGES small (1-4).  If high performance is manditory
54 * perhaps up to 8 pages might be in order????
55 * Above problem has been fixed, now we support 16 pages per block.  Unused
56 * space is recovered by the swap pager now...
57 */
58#define SWB_NPAGES 8
59struct swblock {
60	unsigned short swb_valid;	/* bitmask for valid pages */
61	unsigned short swb_locked;	/* block locked */
62	int swb_block[SWB_NPAGES];	/* unfortunately int instead of daddr_t */
63};
64typedef struct swblock *sw_blk_t;
65
66/*
67 * Swap pager private data.
68 */
69struct swpager {
70	vm_size_t sw_osize;	/* size of object we are backing (bytes) */
71	int sw_nblocks;		/* number of blocks in list (sw_blk_t units) */
72	int sw_allocsize;	/* amount of space actually allocated */
73	sw_blk_t sw_blocks;	/* pointer to list of swap blocks */
74	short sw_flags;		/* flags */
75	short sw_poip;		/* pageouts in progress */
76	short sw_piip;		/* pageins in progress */
77};
78typedef struct swpager *sw_pager_t;
79
80#define	SW_WANTED	0x01
81#define SW_NAMED	0x02
82
83#ifdef KERNEL
84
85void swap_pager_init(void);
86vm_pager_t swap_pager_alloc(void *, vm_size_t, vm_prot_t, vm_offset_t);
87void swap_pager_dealloc(vm_pager_t);
88boolean_t swap_pager_getpage(vm_pager_t, vm_page_t, boolean_t);
89boolean_t swap_pager_putpage(vm_pager_t, vm_page_t, boolean_t);
90boolean_t swap_pager_getmulti(vm_pager_t, vm_page_t *, int, int, boolean_t);
91boolean_t swap_pager_haspage(vm_pager_t, vm_offset_t);
92int swap_pager_io(sw_pager_t, vm_page_t *, int, int, int);
93void swap_pager_iodone(struct buf *);
94boolean_t swap_pager_clean();
95void swap_pager_copy __P((vm_pager_t, vm_offset_t, vm_pager_t, vm_offset_t, vm_offset_t));
96void swap_pager_freespace __P((vm_pager_t, vm_offset_t, vm_offset_t));
97
98extern struct pagerops swappagerops;
99
100#endif
101
102#endif				/* _SWAP_PAGER_ */
103