78 lines
2.8 KiB
Groff
78 lines
2.8 KiB
Groff
.\" $NetBSD: chooseproc.9,v 1.2 2002/09/27 08:38:58 wiz Exp $
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.\"
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.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Gregory McGarry.
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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, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, 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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd September 21, 2002
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.Dt CHOOSEPROC 9
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.Os
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.Sh NAME
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.Nm chooseproc
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.Nd select next process from system run queue
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.Sh SYNOPSIS
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.Fd #include \*[Lt]sys/proc.h\*[Gt]
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.Ft struct proc *
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.Fn chooseproc "void"
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.Sh DESCRIPTION
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The
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.Fn chooseproc
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function is invoked by the scheduler to select the highest priority
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process from the system run queue.
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If a process is not available on the system run queue,
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.Fn chooseproc
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shall go into an
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.Dq idle
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loop by invoking
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.Xr cpu_idle 9 .
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The variable
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.Va curproc
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is set to
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.Dv NULL
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while
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.Fn chooseproc
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is idle so that CPU time is not allocated to the outgoing process.
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.Pp
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The
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.Fn chooseproc
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function must be called with the scheduler lock held
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.Pq see Xr SCHED_LOCK 9
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and at the
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.Xr splsched 9
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interrupt protection level.
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.Sh SEE ALSO
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.Xr cpu_idle 9 ,
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.Xr mi_switch 9 ,
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.Xr scheduler 9 ,
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.Xr splsched 9
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