Annotation of sys/uvm/uvm_anon.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: uvm_anon.h,v 1.14 2007/06/18 21:51:15 pedro Exp $ */
2: /* $NetBSD: uvm_anon.h,v 1.13 2000/12/27 09:17:04 chs Exp $ */
3:
4: /*
5: *
6: * Copyright (c) 1997 Charles D. Cranor and Washington University.
7: * All rights reserved.
8: *
9: * Redistribution and use in source and binary forms, with or without
10: * modification, are permitted provided that the following conditions
11: * are met:
12: * 1. Redistributions of source code must retain the above copyright
13: * notice, this list of conditions and the following disclaimer.
14: * 2. Redistributions in binary form must reproduce the above copyright
15: * notice, this list of conditions and the following disclaimer in the
16: * documentation and/or other materials provided with the distribution.
17: * 3. All advertising materials mentioning features or use of this software
18: * must display the following acknowledgement:
19: * This product includes software developed by Charles D. Cranor and
20: * Washington University.
21: * 4. The name of the author may not be used to endorse or promote products
22: * derived from this software without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34: */
35:
36: #ifndef _UVM_UVM_ANON_H_
37: #define _UVM_UVM_ANON_H_
38:
39: /*
40: * uvm_anon.h
41: */
42:
43: /*
44: * anonymous memory management
45: *
46: * anonymous virtual memory is short term virtual memory that goes away
47: * when the processes referencing it go away. an anonymous page of
48: * virtual memory is described by the following data structure:
49: */
50:
51: struct vm_anon {
52: struct vm_page *an_page; /* if in RAM [an_lock] */
53: int an_ref; /* reference count [an_lock] */
54: int an_swslot; /* drum swap slot # (if != 0)
55: [an_lock. also, it is ok to read
56: an_swslot if we hold an_page PG_BUSY] */
57: simple_lock_data_t an_lock; /* lock for an_ref */
58: };
59:
60: /*
61: * for active vm_anon's the data can be in one of the following state:
62: * [1] in a vm_page with no backing store allocated yet, [2] in a vm_page
63: * with backing store allocated, or [3] paged out to backing store
64: * (no vm_page).
65: *
66: * for pageout in case [2]: if the page has been modified then we must
67: * flush it out to backing store, otherwise we can just dump the
68: * vm_page.
69: */
70:
71: /*
72: * anons are grouped together in anonymous memory maps, or amaps.
73: * amaps are defined in uvm_amap.h.
74: */
75:
76: /*
77: * processes reference anonymous virtual memory maps with an anonymous
78: * reference structure:
79: */
80:
81: struct vm_aref {
82: int ar_pageoff; /* page offset into amap we start */
83: struct vm_amap *ar_amap; /* pointer to amap */
84: };
85:
86: /*
87: * the offset field indicates which part of the amap we are referencing.
88: * locked by vm_map lock.
89: */
90:
91: #ifdef _KERNEL
92:
93: /*
94: * prototypes
95: */
96:
97: struct vm_anon *uvm_analloc(void);
98: void uvm_anfree(struct vm_anon *);
99: void uvm_anon_init(void);
100: struct vm_page *uvm_anon_lockloanpg(struct vm_anon *);
101: void uvm_anon_dropswap(struct vm_anon *);
102: boolean_t uvm_anon_pagein(struct vm_anon *);
103: #endif /* _KERNEL */
104:
105: #endif /* _UVM_UVM_ANON_H_ */
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