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Diffstat (limited to 'static/netbsd/man9/kpreempt.9')
| -rw-r--r-- | static/netbsd/man9/kpreempt.9 | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/static/netbsd/man9/kpreempt.9 b/static/netbsd/man9/kpreempt.9 new file mode 100644 index 00000000..57c48914 --- /dev/null +++ b/static/netbsd/man9/kpreempt.9 @@ -0,0 +1,87 @@ +.\" $NetBSD: kpreempt.9,v 1.3 2010/02/16 19:21:30 rmind Exp $ +.\" +.\" Copyright (c)2008 YAMAMOTO Takashi, +.\" 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, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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. +.\" +.\" ------------------------------------------------------------ +.Dd February 16, 2010 +.Dt KPREEMPT 9 +.Os +.\" ------------------------------------------------------------ +.Sh NAME +.Nm kpreempt +.Nd control kernel preemption +.\" ------------------------------------------------------------ +.Sh SYNOPSIS +.In sys/systm.h +.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +.Ft void +.Fn kpreempt_disable \ +"void" +.Ft void +.Fn kpreempt_enable \ +"void" +.Ft bool +.Fn kpreempt_disabled \ +"void" +.\" ------------------------------------------------------------ +.Sh DESCRIPTION +These functions are used to control kernel preemption of the calling LWP. +.Pp +On architectures where kernel preemption is not supported natively, these +functions may still be used. +.Pp +It should be noted that kernel preemption is also disabled when holding +the interrupt priority level above IPL_NONE, e.g. using +.Xr spl 9 +or spinning +.Xr mutex 9 +calls or holding kernel_lock (indicating that the code is not MT safe). +.Pp +.Fn kpreempt_disable +disables kernel preemption of the calling LWP. +Note that disabling kernel preemption can prevent LWPs with higher priorities +from running. +.Pp +.Fn kpreempt_enable +enables kernel preemption of the calling LWP, which was previously disabled by +.Fn kpreempt_disable . +.Pp +.Fn kpreempt_disable +and +.Fn kpreempt_enable +can be nested. +.Pp +.Fn kpreempt_disabled +returns +.Dv true +if preemption of the calling LWP is disabled. +It is only for diagnostic purpose. +.\" ------------------------------------------------------------ +.\" .Sh RETURN VALUES +.\" ------------------------------------------------------------ +.Sh SEE ALSO +.Xr intro 9 , +.Xr mutex 9 , +.Xr spl 9 |