.\" .\" Copyright (C) 2001 Chad David . 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: src/share/man/man9/vm_page_io.9,v 1.5.22.2.2.1 2010/12/21 17:09:25 kensmith Exp $ .\" .Dd July 17, 2001 .Dt VM_PAGE_IO_START 9 .Os .Sh NAME .Nm vm_page_io_start , .Nm vm_page_io_finish .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_finish "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 one. .Pp The .Fn vm_page_io_finish function lowers the busy count on the page by one, if the resulting busy count is zero, a .Xr wakeup 9 will be issued if the page has been marked .Dv VPO_WANTED . A page is typically marked .Dv VPO_WANTED by a thread to register its interest in the page to either complete I/O or becoming available for general use. .Sh AUTHORS .An -nosplit This manual page was written by .An Chad David Aq davidc@acns.ab.ca and .An Alfred Perlstein Aq alfred@FreeBSD.org .