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BUS_GET_CPUS.9
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.\" -*- nroff -*-
.\"
.\" Copyright (c) 2016 John H. Baldwin <jhb@FreeBSD.org>
.\" 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.
.\"
.\" $FreeBSD$
.\"
.Dd March 1, 2016
.Dt BUS_GET_CPUS 9
.Os
.Sh NAME
.Nm BUS_GET_CPUS ,
.Nm bus_get_cpus
.Nd "request a set of device-specific CPUs"
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.In sys/cpuset.h
.Ft int
.Fo BUS_GET_CPUS
.Fa "device_t dev" "device_t child" "enum cpu_sets op" "size_t setsize"
.Fa "cpuset_t *cpuset"
.Fc
.Ft int
.Fo bus_get_cpus
.Fa "device_t dev" "enum cpu_sets op" "size_t setsize" "cpuset_t *cpuset"
.Fc
.Sh DESCRIPTION
The
.Fn BUS_GET_CPUS
method queries the parent bus device for a set of device-specific CPUs.
The
.Fa op
argument specifies which set of CPUs to retrieve.
If successful,
the requested set of CPUs are returned in
.Fa cpuset .
The
.Fa setsize
argument specifies the size in bytes of the set passed in
.Fa cpuset .
.Pp
.Fn BUS_GET_CPUS
supports querying different types of CPU sets via the
.Fa op argument.
Not all set types are supported for every device.
If a set type is not supported,
.Fn BUS_GET_CPUS
fails with
.Er EINVAL .
These set types are supported:
.Bl -tag -width ".Dv LOCAL_CPUS"
.It Dv LOCAL_CPUS
The set of CPUs that are local to the device.
If a device is closer to a specific memory domain in a non-uniform memory
architecture system
.Pq NUMA ,
this will return the set of CPUs in that memory domain.
.It Dv INTR_CPUS
The preferred set of CPUs that this device should use for device interrupts.
This set type must be supported by all bus drivers.
.El
.Pp
The
.Fn bus_get_cpus
function is a simple wrapper around
.Fn BUS_GET_CPUS .
.Sh RETURN VALUES
Zero is returned on success, otherwise an appropriate error is returned.
.Sh SEE ALSO
.Xr cpuset 2 ,
.Xr BUS_BIND_INTR 9 ,
.Xr device 9
.Sh HISTORY
The
.Fn BUS_GET_CPUS
method and
.Fn bus_get_cpus
function first appeared in
.Fx 11.0 .