117 lines
3.6 KiB
C
117 lines
3.6 KiB
C
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/* $NetBSD: uvm_anon.h,v 1.30 2011/08/06 17:25:03 rmind Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _UVM_UVM_ANON_H_
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#define _UVM_UVM_ANON_H_
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/*
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* uvm_anon.h
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*/
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#if defined(_KERNEL_OPT)
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#include "opt_vmswap.h"
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#endif
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/*
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* anonymous memory management
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*
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* anonymous virtual memory is short term virtual memory that goes away
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* when the processes referencing it go away. an anonymous page of
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* virtual memory is described by the following data structure:
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*/
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struct vm_anon {
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kmutex_t *an_lock; /* Lock for an_ref */
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union {
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uintptr_t au_ref; /* Reference count [an_lock] */
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struct vm_anon *au_link; /* Link for deferred free */
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} an_u;
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#define an_ref an_u.au_ref
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#define an_link an_u.au_link
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struct vm_page *an_page; /* If in RAM [an_lock] */
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#if defined(VMSWAP) || 1 /* XXX libkvm */
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/*
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* Drum swap slot # (if != 0) [an_lock. also, it is ok to read
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* an_swslot if we hold an_page PG_BUSY].
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*/
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int an_swslot;
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#endif
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};
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/*
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* for active vm_anon's the data can be in one of the following state:
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* [1] in a vm_page with no backing store allocated yet, [2] in a vm_page
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* with backing store allocated, or [3] paged out to backing store
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* (no vm_page).
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*
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* for pageout in case [2]: if the page has been modified then we must
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* flush it out to backing store, otherwise we can just dump the
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* vm_page.
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*/
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/*
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* anons are grouped together in anonymous memory maps, or amaps.
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* amaps are defined in uvm_amap.h.
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*/
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/*
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* processes reference anonymous virtual memory maps with an anonymous
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* reference structure:
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*/
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struct vm_aref {
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int ar_pageoff; /* page offset into amap we start */
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struct vm_amap *ar_amap; /* pointer to amap */
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};
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/*
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* the offset field indicates which part of the amap we are referencing.
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* locked by vm_map lock.
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*/
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#ifdef _KERNEL
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/*
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* prototypes
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*/
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struct vm_anon *uvm_analloc(void);
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void uvm_anon_free(struct vm_anon *);
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void uvm_anon_freelst(struct vm_amap *, struct vm_anon *);
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void uvm_anon_init(void);
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struct vm_page *uvm_anon_lockloanpg(struct vm_anon *);
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#if defined(VMSWAP)
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void uvm_anon_dropswap(struct vm_anon *);
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#else /* defined(VMSWAP) */
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#define uvm_anon_dropswap(a) /* nothing */
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#endif /* defined(VMSWAP) */
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void uvm_anon_release(struct vm_anon *);
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bool uvm_anon_pagein(struct vm_amap *, struct vm_anon *);
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#endif /* _KERNEL */
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#endif /* _UVM_UVM_ANON_H_ */
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