1 /* $OpenBSD: uvm_anon.h,v 1.15 2010/06/14 10:05:37 thib 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 * anonymous memory management 41 * 42 * anonymous virtual memory is short term virtual memory that goes away 43 * when the processes referencing it go away. an anonymous page of 44 * virtual memory is described by the following data structure: 45 */ 46 47 struct vm_anon { 48 struct vm_page *an_page; /* if in RAM [an_lock] */ 49 int an_ref; /* reference count [an_lock] */ 50 51 /* 52 * Drum swap slot # (if != 0) [an_lock or not, if we hold an_page 53 * PG_BUSY] 54 */ 55 int an_swslot; 56 57 simple_lock_data_t an_lock; 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 * Note that the offset field indicates which part of the amap we are 80 * referencing. 81 * Locked by vm_map lock. 82 */ 83 84 struct vm_aref { 85 int ar_pageoff; /* page offset into amap we start */ 86 struct vm_amap *ar_amap; /* pointer to amap */ 87 }; 88 89 #ifdef _KERNEL 90 struct vm_anon *uvm_analloc(void); 91 void uvm_anfree(struct vm_anon *); 92 void uvm_anon_init(void); 93 struct vm_page *uvm_anon_lockloanpg(struct vm_anon *); 94 void uvm_anon_dropswap(struct vm_anon *); 95 boolean_t uvm_anon_pagein(struct vm_anon *); 96 #endif /* _KERNEL */ 97 98 #endif /* _UVM_UVM_ANON_H_ */ 99