229 lines
6.0 KiB
Groff
229 lines
6.0 KiB
Groff
.\" $NetBSD: swapctl.2,v 1.12 1999/03/22 19:45:10 garbled Exp $
|
|
.\"
|
|
.\" Copyright (c) 1997 Matthew R. Green
|
|
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. 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.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 June 20, 1997
|
|
.Dt SWAPCTL 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm swapctl
|
|
.Nd modify swap configuration
|
|
.Sh SYNOPSIS
|
|
.Fd #include <unistd.h>
|
|
.Fd #include <sys/swap.h>
|
|
.Ft int
|
|
.Fn swapctl "int cmd" "const void *arg" "int misc"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
function is used to add and delete swap devices, and modify their
|
|
configuration.
|
|
.Pp
|
|
The
|
|
.Fa cmd
|
|
parameter specifies the operation to be performed. The
|
|
.Fa arg
|
|
and
|
|
.Fa misc
|
|
parameters have different meanings, depending on the
|
|
.Fa cmd
|
|
parameter.
|
|
.Bl -item -offset indent
|
|
.It
|
|
If
|
|
.Fa cmd
|
|
is
|
|
.Dv SWAP_NSWAP ,
|
|
the current number of swap devices in the system is returned. The
|
|
.Fa arg
|
|
and
|
|
.Fa misc
|
|
parameters are ignored.
|
|
.It
|
|
If
|
|
.Fa cmd
|
|
is
|
|
.Dv SWAP_STATS ,
|
|
the current statistics for swap devices are returned in the
|
|
.Fa arg
|
|
parameter. No more than
|
|
.Fa misc
|
|
swap devices are returned. The
|
|
.Fa arg
|
|
parameter should point to an array of at least
|
|
.Fa misc
|
|
struct swapent structures:
|
|
.Bd -literal
|
|
struct swapent {
|
|
dev_t se_dev; /* device id */
|
|
int se_flags; /* entry flags */
|
|
int se_nblks; /* total blocks */
|
|
int se_inuse; /* blocks in use */
|
|
int se_priority; /* priority */
|
|
char se_path[PATH_MAX+1]; /* path to entry */
|
|
};
|
|
.Ed
|
|
.Pp
|
|
The flags are defined as
|
|
.Bd -literal
|
|
SWF_INUSE in use: we have swapped here
|
|
SWF_ENABLE enabled: we can swap here
|
|
SWF_BUSY busy: I/O happening here
|
|
SWF_FAKE fake: still being built
|
|
.Ed
|
|
.It
|
|
If
|
|
.Fa cmd
|
|
is
|
|
.Dv SWAP_ON ,
|
|
the
|
|
.Fa arg
|
|
parameter is used as a pathname of a file to enable swapping to.
|
|
The
|
|
.Fa misc
|
|
parameter is used to set the priority of this swap device.
|
|
.It
|
|
If
|
|
.Fa cmd
|
|
is
|
|
.Dv SWAP_OFF ,
|
|
the
|
|
.Fa arg
|
|
parameter is used as the pathname of a file to disable swapping from.
|
|
The
|
|
.Fa misc
|
|
parameter is ignored.
|
|
.It
|
|
If
|
|
.Fa cmd
|
|
is
|
|
.Dv SWAP_CTL ,
|
|
the
|
|
.Fa arg
|
|
and
|
|
.Fa misc
|
|
parameters have the same function as for the
|
|
.Dv SWAP_ON
|
|
case, except that they change the priority of a currently enabled swap device.
|
|
.El
|
|
.Pp
|
|
When swapping is enabled on a block device, the first portion of the disk is
|
|
left unused to prevent any disklable present from being overwritten. This
|
|
space is allocated from the swap device when the
|
|
.Dv SWAP_ON
|
|
command is used.
|
|
.Sh RETURN VALUES
|
|
If the
|
|
.Fa cmd
|
|
parameter is
|
|
.Dv SWAP_NSWAP
|
|
or
|
|
.Dv SWAP_STATS ,
|
|
.Fn swapctl
|
|
returns the number of swap devices, if successful. The
|
|
.Dv SWAP_NSWAP
|
|
command is always successful. Otherwise it returns 0 on success and -1
|
|
on failure, setting the global variable
|
|
.Va errno
|
|
to indicate the error.
|
|
.Sh ERRORS
|
|
.Fn swapctl
|
|
succeeds unless:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOTDIR
|
|
A component of the path prefix is not a directory.
|
|
.It Bq Er ENAMETOOLONG
|
|
A component of a pathname exceeded
|
|
.Dv NAME_MAX
|
|
characters, or an entire path name exceeded
|
|
.Dv PATH_MAX
|
|
characters.
|
|
.It Bq Er ENOENT
|
|
The named device does not exist. For the
|
|
.Dv SWAP_CTL
|
|
command, the named device is not currently enabled for swapping.
|
|
.It Bq Er EACCES
|
|
Search permission is denied for a component of the path prefix.
|
|
.It Bq Er ELOOP
|
|
Too many symbolic links were encountered in translating the pathname.
|
|
.It Bq Er EPERM
|
|
The caller is not the super-user.
|
|
.It Bq Er EBUSY
|
|
The device specified by
|
|
.Fa arg
|
|
has already been made available for swapping.
|
|
.It Bq Er EINVAL
|
|
The device configured by
|
|
.Fa arg
|
|
has no associated size, or the
|
|
.Fa cmd
|
|
was unknown.
|
|
.It Bq Er ENXIO
|
|
The major device number of
|
|
.Fa arg
|
|
is out of range (this indicates no device driver exists
|
|
for the associated hardware).
|
|
.It Bq Er EIO
|
|
An I/O error occurred while opening the swap device.
|
|
.It Bq Er EFAULT
|
|
.Fa arg
|
|
points outside the process' allocated address space.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr swapctl 8 ,
|
|
.Xr config 8
|
|
.Sh BUGS
|
|
The
|
|
.Dv SWAP_OFF
|
|
command is currently unimplemented by the
|
|
.Nx
|
|
kernel.
|
|
.Sh AUTHOR
|
|
The current swap system was designed and implemented by Matthew Green
|
|
<mrg@eterna.com.au>, with help from Paul Kranenburg <pk@NetBSD.ORG>
|
|
and Leo Weppelman <leo@NetBSD.ORG>, and insights from Jason R. Thorpe
|
|
<thorpej@NetBSD.ORG>.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn swapctl
|
|
function call appeared in
|
|
.Nx 1.3 .
|
|
The
|
|
.Fa se_path
|
|
member was added to
|
|
.Va struct swapent
|
|
in
|
|
.Nx 1.4 ,
|
|
when the header file was also moved from
|
|
.Pa <vm/vm_swap.h> .
|