xref: /freebsd/share/man/man9/vm_map_findspace.9 (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1.\"
2.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org>
3.\" All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\"    notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\"    notice, this list of conditions and the following disclaimer in the
12.\"    documentation and/or other materials provided with the distribution.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24.\" SUCH DAMAGE.
25.\"
26.Dd July 19, 2003
27.Dt VM_MAP_FINDSPACE 9
28.Os
29.Sh NAME
30.Nm vm_map_findspace
31.Nd find a free region within a map
32.Sh SYNOPSIS
33.In sys/param.h
34.In vm/vm.h
35.In vm/vm_map.h
36.Ft int
37.Fo vm_map_findspace
38.Fa "vm_map_t map" "vm_offset_t start" "vm_size_t length" "vm_offset_t *addr"
39.Fc
40.Sh DESCRIPTION
41The
42.Fn vm_map_findspace
43function attempts to find a region with sufficient space in the
44.Fa map
45for an object of size
46.Fa length
47at the address
48.Fa addr .
49.Sh IMPLEMENTATION NOTES
50It is the caller's responsibility to obtain a lock on the
51.Fa map
52using
53.Xr vm_map_lock 9
54before calling this function.
55.Pp
56This routine may call
57.Xr pmap_growkernel 9
58to grow the kernel's address space, if and only if the mapping is being
59made within the kernel address space, and if insufficient space remains
60in the
61.Va kernel_map .
62.Sh RETURN VALUES
63The
64.Fn vm_map_findspace
65function returns the value 0 if successful, and
66.Fa *addr
67will contain the first virtual address in the found region;
68otherwise, the value 1 is returned.
69.Sh SEE ALSO
70.Xr pmap_growkernel 9 ,
71.Xr vm_map 9 ,
72.Xr vm_map_entry_resize_free 9 ,
73.Xr vm_map_lock 9
74.Sh AUTHORS
75This manual page was written by
76.An Bruce M Simpson Aq Mt bms@spc.org .
77