.\"     $NetBSD: SCHED_LOCK.9,v 1.4 2003/04/16 13:35:24 wiz Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Gregory McGarry.
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.Dd September 21, 2002
.Dt SCHED_LOCK 9
.Os
.Sh NAME
.Nm SCHED_LOCK ,
.Nm SCHED_UNLOCK ,
.Nm sched_lock_idle ,
.Nm sched_unlock_idle
.Nd scheduler lock operations
.Sh SYNOPSIS
.In sys/sched.h
.Ft void
.Fn sched_lock_idle "void"
.Ft void
.Fn sched_unlock_idle "void"
.Ft int
.Fn SCHED_LOCK "void"
.Ft void
.Fn SCHED_UNLOCK "int s"
.Sh DESCRIPTION
Access to the system run queue within the scheduler is protected by the
.Va sched_lock
simplelock and the
.Xr splsched 9
interrupt priority level.
The
.Fn sched_lock_idle
and
.Fn sched_unlock_idle
are simple functions without arguments which can be called easily from
machine-dependent assembler routines
.Pq such as from Xr cpu_idle 9
to lock and unlock the scheduler.
The macros
.Fn SCHED_LOCK
and
.Fn SCHED_UNLOCK
provide a simple interface for machine-independent routines to
simultaneously acquire
.Va sched_lock
and raise the interrupt priority level to
.Xr splsched 9 .
.Fn SCHED_LOCK
returns the current interrupt priority level which is later passed to
.Fn SCHED_UNLOCK
when the scheduler lock is released.
.Sh SEE ALSO
.Xr scheduler 9 ,
.Xr splsched 9