Copyright (c) 2003 Bruce M Simpson <bms@spc.org>
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, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.

$FreeBSD: head/share/man/man9/vm_map_wire.9 131680 2004-07-06 06:53:42Z ru $

.Dd July 19, 2003 .Dt VM_MAP_WIRE 9 .Sh NAME .Nm vm_map_wire , .Nm vm_map_unwire .Nd manage page wiring within a virtual memory map .Sh SYNOPSIS n sys/param.h n vm/vm.h n vm/vm_map.h .Ft int .Fn vm_map_wire "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "int flags" .Ft int .Fo vm_map_unwire .Fa "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "int flags" .Fc .Sh DESCRIPTION The .Fn vm_map_wire function is responsible for wiring pages in the range between .Fa start and .Fa end within the map .Fa map . Wired pages are locked into physical memory, and may not be paged out as long as their wire count remains above zero.

p The .Fn vm_map_unwire function performs the corresponding unwire operation.

p The .Fa flags argument is a bit mask, consisting of the following flags:

p If the .Dv VM_MAP_WIRE_USER flag is set, the function operates within user address space.

p If the .Dv VM_MAP_WIRE_HOLESOK flag is set, it may operate upon an arbitrary range within the address space of .Fa map .

p If a contiguous range is desired, callers should explicitly express their intent by specifying the .Dv VM_MAP_WIRE_NOHOLES flag. .Sh IMPLEMENTATION NOTES Both functions will attempt to acquire a lock on the map using .Xr vm_map_lock 9 and hold it for the duration of the call. If they detect .Dv MAP_ENTRY_IN_TRANSITION , they will call .Xr vm_map_unlock_and_wait 9 until the map becomes available again.

p The map could have changed during this window as it was held by another consumer, therefore consumers of this interface should check for this condition using the return values below. .Sh RETURN VALUES The .Fn vm_map_wire and .Fn vm_map_unwire functions have identical return values. The functions return .Dv KERN_SUCCESS if all pages within the range were [un]wired successfully.

p Otherwise, if the specified range was not valid, or if the map changed while the .Dv MAP_ENTRY_IN_TRANSITION flag was set, .Dv KERN_INVALID_ADDRESS is returned. .Sh SEE ALSO .Xr mlockall 2 , .Xr munlockall 2 , .Xr vm_map 9 .Sh AUTHORS This man page was written by .An Bruce M Simpson Aq bms@spc.org .