| 1 | /* $NetBSD: uvm_anon.h,v 1.30 2011/08/06 17:25:03 rmind Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1997 Charles D. Cranor and Washington University. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #ifndef _UVM_UVM_ANON_H_ |
| 29 | #define _UVM_UVM_ANON_H_ |
| 30 | |
| 31 | /* |
| 32 | * uvm_anon.h |
| 33 | */ |
| 34 | |
| 35 | #if defined(_KERNEL_OPT) |
| 36 | #include "opt_vmswap.h" |
| 37 | #endif |
| 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 | kmutex_t *an_lock; /* Lock for an_ref */ |
| 49 | union { |
| 50 | uintptr_t au_ref; /* Reference count [an_lock] */ |
| 51 | struct vm_anon *au_link; /* Link for deferred free */ |
| 52 | } an_u; |
| 53 | #define an_ref an_u.au_ref |
| 54 | #define an_link an_u.au_link |
| 55 | struct vm_page *an_page; /* If in RAM [an_lock] */ |
| 56 | #if defined(VMSWAP) || 1 /* XXX libkvm */ |
| 57 | /* |
| 58 | * Drum swap slot # (if != 0) [an_lock. also, it is ok to read |
| 59 | * an_swslot if we hold an_page PG_BUSY]. |
| 60 | */ |
| 61 | int an_swslot; |
| 62 | #endif |
| 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_anon_free(struct vm_anon *); |
| 104 | void uvm_anon_freelst(struct vm_amap *, struct vm_anon *); |
| 105 | void uvm_anon_init(void); |
| 106 | struct vm_page *uvm_anon_lockloanpg(struct vm_anon *); |
| 107 | #if defined(VMSWAP) |
| 108 | void uvm_anon_dropswap(struct vm_anon *); |
| 109 | #else /* defined(VMSWAP) */ |
| 110 | #define uvm_anon_dropswap(a) /* nothing */ |
| 111 | #endif /* defined(VMSWAP) */ |
| 112 | void uvm_anon_release(struct vm_anon *); |
| 113 | bool uvm_anon_pagein(struct vm_amap *, struct vm_anon *); |
| 114 | #endif /* _KERNEL */ |
| 115 | |
| 116 | #endif /* _UVM_UVM_ANON_H_ */ |
| 117 | |