1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
.\"
.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice(s), this list of conditions and the following disclaimer as
.\" the first lines of this file unmodified other than the possible
.\" addition of one or more copyright notices.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice(s), this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
.\" DAMAGE.
.\"
.Dd September 9, 2019
.Dt VM_PAGE_WIRE 9
.Os
.Sh NAME
.Nm vm_page_wire ,
.Nm vm_page_unwire ,
.Nm vm_page_unwire_noq
.Nd "wire and unwire pages"
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/vm_page.h
.Ft void
.Fn vm_page_wire "vm_page_t m"
.Ft bool
.Fn vm_page_wire_mapped "vm_page_t m"
.Ft void
.Fn vm_page_unwire "vm_page_t m" "int queue"
.Ft bool
.Fn vm_page_unwire_noq "vm_page_t m"
.Sh DESCRIPTION
The
.Fn vm_page_wire
and
.Fn vm_page_wire_mapped
functions wire the page, which prevents it from being reclaimed by the page
daemon or when its containing object is destroyed.
Both functions require that the page belong to an object.
The
.Fn vm_page_wire_mapped
function is for use by the
.Xr pmap 9
layer following a lookup.
This function may fail if mappings of the page are concurrently
being destroyed, in which case it will return false.
.Pp
The
.Fn vm_page_unwire
and
.Fn vm_page_unwire_noq
functions release a wiring of a page.
The
.Fn vm_page_unwire
function takes a queue index and will insert the page into the
corresponding page queue upon releasing its last wiring.
If the page does not belong to an object and no other references
to the page exist,
.Fn vm_page_unwire
will free the page.
.Fn vm_page_unwire_noq
releases the wiring and returns true if it was the last wiring
of the page.
.Sh AUTHORS
This manual page was written by
.An Chad David Aq Mt davidc@acns.ab.ca .
|
