.\"
.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\" $FreeBSD$
.\"
.Dd July 17, 2001
.Dt VM_PAGE_IO_START 9
.Os
.Sh NAME
.Nm vm_page_io_start ,
.Nm vm_page_io_finished
.Nd "ready or unready a page for I/O"
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/vm_page.h
.Ft void
.Fn vm_page_io_start "vm_page_t m"
.Ft void
.Fn vm_page_io_finised "vm_page_t m"
.Sh DESCRIPTION
The
.Fn vm_page_io_start
function prepares the page for I/O by incrementing its busy flag by 1.
.Pp
The
.Fn vm_page_io_finished
function lowers the busy count on the page by one, if the resulting busy
count is zero, a wakeup will be issued if the page has been marked PG_WANTED.
A page is typically marked PG_WANTED by a thread to register interested in
the page either completing I/O or becoming available for general use.
.Sh AUTHORS
This man page was written by
.An Chad David Aq davidc@acns.ab.ca ,
and
.An Alfred Perlstein Aq alfred@freebsd.org .