2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
146 lines
4.2 KiB
Groff
146 lines
4.2 KiB
Groff
.\" $NetBSD: _lwp_park.2,v 1.7 2008/04/30 13:10:51 martin Exp $
|
|
.\"
|
|
.\" Copyright (c) 2003, 2007 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Jason R. Thorpe of Wasabi Systems, Inc, and by Andrew Doran.
|
|
.\"
|
|
.\" 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 September 25, 2007
|
|
.Dt _LWP_PARK 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm _lwp_park
|
|
.Nd wait interruptably in the kernel
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In lwp.h
|
|
.Ft int
|
|
.Fn _lwp_park "const struct timespec *abstime" "lwpid_t unpark" "const void *hint" "const void *unparkhint"
|
|
.Sh DESCRIPTION
|
|
.Fn _lwp_park
|
|
can be used to synchronize access to resources among multiple light-weight
|
|
processes.
|
|
It causes the calling LWP to wait interruptably in the kernel, until one
|
|
of the following conditions is met:
|
|
.Bl -bullet
|
|
.It
|
|
The
|
|
.Fa abstime
|
|
argument is non-NULL, and the absolute UTC time it specifies has passed.
|
|
.It
|
|
The LWP receives a directed signal posted using
|
|
.Fn _lwp_kill ,
|
|
or is elected to handle a signal on behalf of its containing process.
|
|
.It
|
|
The LWP is awoken by another LWP in the same process that has made
|
|
a call to
|
|
.Fn _lwp_wakeup .
|
|
.It
|
|
The LWP is awoken by another LWP in the same process that has made
|
|
a call to
|
|
.Fn _lwp_unpark
|
|
or
|
|
.Fn _lwp_unpark_all .
|
|
.El
|
|
.Pp
|
|
The preferred method to awaken an LWP sleeping as a result of a call
|
|
to
|
|
.Fn _lwp_park
|
|
is to make a call to
|
|
.Fn _lwp_unpark ,
|
|
or
|
|
.Fn _lwp_unpark_all .
|
|
The
|
|
.Fn _lwp_wakeup
|
|
system call is a more general facility, and requires more resources
|
|
to execute.
|
|
.Pp
|
|
The optional
|
|
.Fa hint
|
|
argument specifies the address of object upon which the LWP is
|
|
synchronizing.
|
|
When the
|
|
.Fa hint
|
|
value is matched between calls to
|
|
.Fn _lwp_park
|
|
and
|
|
.Fn _lwp_unpark
|
|
or
|
|
.Fn _lwp_unpark_all ,
|
|
it may reduce the time necessary for the system to resume execution
|
|
of waiting LWPs.
|
|
.Pp
|
|
The
|
|
.Fa unpark
|
|
and
|
|
.Fa unparkhint
|
|
arguments can be used to fold a park operation and unpark operation into a
|
|
single system call.
|
|
If
|
|
.Fa unpark
|
|
is non-zero, the system will behave as if the following call had been made
|
|
before the calling thread begins to wait:
|
|
.Bd -literal
|
|
_lwp_unpark(unpark, unparkhint);
|
|
.Ed
|
|
.Sh RETURN VALUES
|
|
.Fn _lwp_park
|
|
may return a value of 0.
|
|
Otherwise, \-1 is returned and
|
|
.Va errno
|
|
is set to provide more information.
|
|
.Sh ERRORS
|
|
.Bl -tag -width [EINVAL]
|
|
.It Bq Er EALREADY
|
|
A request was made to wake the LWP before it began to wait in
|
|
the kernel.
|
|
.It Bq Er EINTR
|
|
The LWP has been awoken by a signal or by a call to one of the
|
|
following functions:
|
|
.Fn _lwp_unpark ,
|
|
.Fn _lwp_unpark_all ,
|
|
.Fn _lwp_wakeup .
|
|
.It Bq Er EINVAL
|
|
The time value specified by
|
|
.Fa abstime
|
|
is invalid.
|
|
.It Bq Er ESRCH
|
|
No LWP can be found in the current process corresponding to
|
|
.Fa unpark .
|
|
.It Bq Er ETIMEDOUT
|
|
The UTC time specified by
|
|
.Fa abstime
|
|
has passed.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr _lwp_unpark 2 ,
|
|
.Xr _lwp_unpark_all 2 ,
|
|
.Xr _lwp_wakeup 2
|
|
.Sh HISTORY
|
|
The
|
|
.Fn _lwp_park
|
|
system call first appeared in
|
|
.Nx 5.0 .
|