f35093f8d6
Linux has more tolerant checks of the user supplied cpuset_t's. Minimum cpuset_t size that the Linux kernel permits in case of getaffinity() is the maximum CPU id, present in the system / NBBY, the maximum size is not limited. For setaffinity(), Linux does not limit the size of the user-provided cpuset_t, internally using only the meaningful part of the set, where the upper bound is the maximum CPU id, present in the system, no larger than the size of the kernel cpuset_t. Unlike FreeBSD, Linux ignores high bits if set in the setaffinity(), so clear it in the sched_setaffinity() and Linuxulator itself. Reviewed by: Pau Amma (man pages) In collaboration with: jhb Differential revision: https://reviews.freebsd.org/D34849 MFC after: 2 weeks
180 lines
4.9 KiB
Groff
180 lines
4.9 KiB
Groff
.\" Copyright (c) 2008 Christian Brueffer
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.\" Copyright (c) 2008 Jeffrey Roberson
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 27, 2022
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.Dt CPUSET_GETAFFINITY 2
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.Os
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.Sh NAME
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.Nm cpuset_getaffinity ,
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.Nm cpuset_setaffinity
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.Nd manage CPU affinity
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/cpuset.h
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.Ft int
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.Fn cpuset_getaffinity "cpulevel_t level" "cpuwhich_t which" "id_t id" "size_t setsize" "cpuset_t *mask"
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.Ft int
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.Fn cpuset_setaffinity "cpulevel_t level" "cpuwhich_t which" "id_t id" "size_t setsize" "const cpuset_t *mask"
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.Sh DESCRIPTION
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.Fn cpuset_getaffinity
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and
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.Fn cpuset_setaffinity
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allow the manipulation of sets of CPUs available to processes, threads,
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interrupts, jails and other resources.
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These functions may manipulate sets of CPUs that contain many processes
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or per-object anonymous masks that effect only a single object.
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.Pp
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The valid values for the
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.Fa level
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and
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.Fa which
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arguments are documented in
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.Xr cpuset 2 .
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These arguments specify which object and which set of the object we are
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referring to.
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Not all possible combinations are valid.
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For example, only processes may belong to a numbered set accessed by a
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.Fa level
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argument of
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.Dv CPU_LEVEL_CPUSET .
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All resources, however, have a mask which may be manipulated with
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.Dv CPU_LEVEL_WHICH .
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.Pp
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Masks of type
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.Ft cpuset_t
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are composed using the
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.Dv CPU_SET
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macros.
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If the user-supplied mask is not large enough to fit all of the matching CPUs,
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.Fn cpuset_getaffinity
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fails with
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.Er ERANGE .
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Calls to
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.Fn cpuset_setaffinity
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tolerate masks of any size with no restrictions.
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The kernel uses the meaningful part of the mask, where the upper bound is
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the maximum CPU id present in the system.
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If bits for non-existing CPUs are set, calls to
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.Fn cpuset_setaffinity
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fails with
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.Er EINVAL .
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.Pp
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The supplied mask should have a size of
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.Fa setsize
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bytes.
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This size is usually provided by calling
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.Li sizeof(mask)
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which is ultimately determined by the value of
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.Dv CPU_SETSIZE
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as defined in
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.In sys/cpuset.h .
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.Pp
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.Fn cpuset_getaffinity
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retrieves the
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mask from the object specified by
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.Fa level ,
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.Fa which
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and
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.Fa id
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and stores it in the space provided by
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.Fa mask .
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.Pp
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.Fn cpuset_setaffinity
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attempts to set the mask for the object specified by
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.Fa level ,
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.Fa which
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and
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.Fa id
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to the value in
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.Fa mask .
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.Sh RETURN VALUES
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.Rv -std
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.Sh ERRORS
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The following error codes may be set in
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.Va errno :
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.Bl -tag -width Er
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.\" When changing this list, consider updating share/man/man3/pthread_create.3,
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.\" since that function can return any of these errors.
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.It Bq Er EINVAL
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The
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.Fa level
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or
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.Fa which
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argument was not a valid value.
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.It Bq Er EINVAL
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The
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.Fa mask
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argument specified when calling
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.Fn cpuset_setaffinity
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was not a valid value.
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.It Bq Er EDEADLK
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The
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.Fn cpuset_setaffinity
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call would leave a thread without a valid CPU to run on because the set
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does not overlap with the thread's anonymous mask.
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.It Bq Er EFAULT
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The mask pointer passed was invalid.
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.It Bq Er ESRCH
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The object specified by the
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.Fa id
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and
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.Fa which
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arguments could not be found.
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.It Bq Er ERANGE
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The
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.Fa cpusetsize
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was smaller than needed to fit all of the matching CPUs.
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.It Bq Er EPERM
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The calling process did not have the credentials required to complete the
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operation.
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.It Bq Er ECAPMODE
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The calling process attempted to act on a process other than itself, while
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in capability mode.
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See
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.Xr capsicum 4 .
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.El
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.Sh SEE ALSO
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.Xr cpuset 1 ,
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.Xr cpuset 2 ,
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.Xr cpuset_getdomain 2 ,
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.Xr cpuset_getid 2 ,
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.Xr cpuset_setdomain 2 ,
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.Xr cpuset_setid 2 ,
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.Xr pthread_affinity_np 3 ,
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.Xr pthread_attr_affinity_np 3 ,
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.Xr capsicum 4 ,
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.Xr cpuset 9
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.Sh HISTORY
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The
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.Nm
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family of system calls first appeared in
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.Fx 7.1 .
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.Sh AUTHORS
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.An Jeffrey Roberson Aq Mt jeff@FreeBSD.org
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