1 /* $NetBSD: uvm_anon.h,v 1.23 2005/12/11 12:25:29 christos Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 #ifndef _UVM_UVM_ANON_H_ 36 #define _UVM_UVM_ANON_H_ 37 38 /* 39 * uvm_anon.h 40 */ 41 42 #if defined(_KERNEL_OPT) 43 #include "opt_vmswap.h" 44 #endif 45 46 /* 47 * anonymous memory management 48 * 49 * anonymous virtual memory is short term virtual memory that goes away 50 * when the processes referencing it go away. an anonymous page of 51 * virtual memory is described by the following data structure: 52 */ 53 54 struct vm_anon { 55 int an_ref; /* reference count [an_lock] */ 56 struct simplelock an_lock; /* lock for an_ref */ 57 struct vm_page *an_page;/* if in RAM [an_lock] */ 58 #if defined(VMSWAP) || 1 /* XXX libkvm */ 59 int an_swslot; /* drum swap slot # (if != 0) 60 [an_lock. also, it is ok to read 61 an_swslot if we hold an_page PG_BUSY] */ 62 #endif /* defined(VMSWAP) */ 63 }; 64 65 /* 66 * for active vm_anon's the data can be in one of the following state: 67 * [1] in a vm_page with no backing store allocated yet, [2] in a vm_page 68 * with backing store allocated, or [3] paged out to backing store 69 * (no vm_page). 70 * 71 * for pageout in case [2]: if the page has been modified then we must 72 * flush it out to backing store, otherwise we can just dump the 73 * vm_page. 74 */ 75 76 /* 77 * anons are grouped together in anonymous memory maps, or amaps. 78 * amaps are defined in uvm_amap.h. 79 */ 80 81 /* 82 * processes reference anonymous virtual memory maps with an anonymous 83 * reference structure: 84 */ 85 86 struct vm_aref { 87 int ar_pageoff; /* page offset into amap we start */ 88 struct vm_amap *ar_amap; /* pointer to amap */ 89 }; 90 91 /* 92 * the offset field indicates which part of the amap we are referencing. 93 * locked by vm_map lock. 94 */ 95 96 #ifdef _KERNEL 97 98 /* 99 * prototypes 100 */ 101 102 struct vm_anon *uvm_analloc(void); 103 void uvm_anfree(struct vm_anon *); 104 void uvm_anon_init(void); 105 struct vm_page *uvm_anon_lockloanpg(struct vm_anon *); 106 #if defined(VMSWAP) 107 void uvm_anon_dropswap(struct vm_anon *); 108 #else /* defined(VMSWAP) */ 109 #define uvm_anon_dropswap(a) /* nothing */ 110 #endif /* defined(VMSWAP) */ 111 void uvm_anon_release(struct vm_anon *); 112 boolean_t uvm_anon_pagein(struct vm_anon *); 113 #endif /* _KERNEL */ 114 115 #endif /* _UVM_UVM_ANON_H_ */ 116