90 lines
2.8 KiB
Groff
90 lines
2.8 KiB
Groff
.\" Copyright (c) 2000-2001 John H. Baldwin <jhb@FreeBSD.org>
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.\" 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, 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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 3, 2000
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.Dt SLEEPQUEUE 9
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.Os
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.Sh NAME
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.Nm endtsleep ,
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.Nm sleepinit ,
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.Nm unsleep
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.Nd manage the queues of sleeping processes
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/proc.h
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.Ft void
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.Fn endtsleep "void *arg"
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.Ft void
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.Fn sleepinit "void"
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.Ft void
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.Fn unsleep "struct thread *td"
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.Sh DESCRIPTION
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The sleep queues used by
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.Xr msleep 9
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and friends are stored in a hash array.
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The address of the wait channel is used to generate an index into the array.
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Each entry in the array is a queue of processes that are sleeping on wait
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channels that hash to that index.
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.Xr msleep 9
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places processes into their appropriate queues directly.
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To handle timeouts, the
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.Fn endtsleep
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function is registered as a
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.Xr timeout 9 .
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When the process is woken by either
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.Fn wakeup
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or
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.Fn wakeup_one ,
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the timeout is revoked via
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.Xr untimeout 9 .
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If the process is not awakened soon enough, then
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.Fn endtsleep
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is called with
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.Fa arg
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pointing to the
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.Vt "struct proc"
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of the process that timed out.
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.Fn endtsleep
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undoes the sleep and makes the process runnable if it is in the
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.Dv SSLEEP
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state.
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The sleep queues and the hash array are protected internally by the
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.Va sched_lock
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mutex.
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.Pp
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.Fn unsleep
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simply removes the thread
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.Fa td
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from its sleep queue.
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.Pp
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.Fn sleepinit
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is called during system startup and initializes the scheduler quantum
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.Pq Va sched_quantum
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and the sleep queues.
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.Sh SEE ALSO
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.Xr msleep 9 ,
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.Xr runqueue 9 ,
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.Xr scheduler 9
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