76 lines
2.7 KiB
Groff
76 lines
2.7 KiB
Groff
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd July 13, 2001
|
|
.Dt VM_PAGE_HOLD 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm vm_page_hold ,
|
|
.Nm vm_page_unhold
|
|
.Nd "update a page's hold count"
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In vm/vm.h
|
|
.In vm/vm_page.h
|
|
.Ft void
|
|
.Fn vm_page_hold "vm_page_t m"
|
|
.Ft void
|
|
.Fn vm_page_unhold "vm_page_t m"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn vm_page_hold
|
|
function increases the hold count on a page.
|
|
This prevents the page daemon from freeing the page.
|
|
.Pp
|
|
.Fn vm_page_hold
|
|
should only be used for very temporary wiring of a page,
|
|
as that page will not be considered for paging or
|
|
reallocation for as long as its hold count is greater
|
|
than zero.
|
|
Also note that while wired pages are removed from whatever
|
|
queue they are on,
|
|
.Fn vm_page_hold
|
|
does not affect the location of the page.
|
|
If it is on a queue prior to the call, it will still
|
|
be there afterward.
|
|
.Pp
|
|
If the page needs to be held for a long period of time,
|
|
.Fn vm_page_write
|
|
should be used.
|
|
.Pp
|
|
.Fn vm_page_unhold
|
|
function reduces the hold count on a page.
|
|
If the hold count is zero it is possible that the page will be freed by the
|
|
page daemon.
|
|
.Sh SEE ALSO
|
|
.Xr vm_page_unwire 9 ,
|
|
.Xr vm_page_wire 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Chad David Aq davidc@acns.ab.ca .
|