64 lines
2.3 KiB
Groff
64 lines
2.3 KiB
Groff
.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 17, 2001
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.Dt VM_PAGE_IO_START 9
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.Os
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.Sh NAME
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.Nm vm_page_io_start ,
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.Nm vm_page_io_finish
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.Nd "ready or unready a page for I/O"
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.Sh SYNOPSIS
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.In sys/param.h
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.In vm/vm.h
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.In vm/vm_page.h
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.Ft void
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.Fn vm_page_io_start "vm_page_t m"
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.Ft void
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.Fn vm_page_io_finish "vm_page_t m"
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.Sh DESCRIPTION
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The
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.Fn vm_page_io_start
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function prepares the page for I/O by incrementing its busy flag by 1.
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.Pp
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The
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.Fn vm_page_io_finish
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function lowers the busy count on the page by one, if the resulting busy
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count is zero, a wakeup will be issued if the page has been marked
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.Dv PG_WANTED .
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A page is typically marked
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.Dv PG_WANTED
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by a thread to register interested in
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the page either completing I/O or becoming available for general use.
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.Sh AUTHORS
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.An -nosplit
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This man page was written by
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.An Chad David Aq davidc@acns.ab.ca
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and
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.An Alfred Perlstein Aq alfred@FreeBSD.org .
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