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CPUSET_GETDOMAIN(2) FreeBSD System Calls Manual CPUSET_GETDOMAIN(2)
NAME
cpuset_getdomain, cpuset_setdomain - manage memory domain policy
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/param.h>
#include <sys/domainset.h>
int
cpuset_getdomain(cpulevel_t level, cpuwhich_t which, id_t id,
size_t setsize, domainset_t *mask, int *policy);
int
cpuset_setdomain(cpulevel_t level, cpuwhich_t which, id_t id,
size_t setsize, const domainset_t *mask, int policy);
DESCRIPTION
cpuset_getdomain() and cpuset_setdomain() allow the manipulation of sets
of memory domains and allocation policy available to processes, threads,
jails and other resources. These functions may manipulate sets of memory
domains that contain many processes or per-object anonymous masks that
affect only a single object.
The valid values for the level and which arguments are documented in
cpuset(2). These arguments specify which object and which set of the
object we are referring to. Not all possible combinations are valid.
For example, only processes may belong to a numbered set accessed by a
level argument of CPU_LEVEL_CPUSET. All resources, however, have a mask
which may be manipulated with CPU_LEVEL_WHICH.
Masks of type domainset_t are composed using the DOMAINSET macros. The
kernel tolerates large sets as long as all domains specified in the set
exist. Sets smaller than the kernel uses generate an error on calls to
cpuset_getdomain() even if the result set would fit within the user
supplied set. Calls to cpuset_setdomain() tolerate small sets with no
restrictions.
The supplied mask should have a size of setsize bytes. This size is
usually provided by calling sizeof(mask) which is ultimately determined
by the value of DOMAINSET_SETSIZE as defined in <sys/domainset.h>.
cpuset_getdomain() retrieves the mask and policy from the object
specified by level, which and id and stores it in the space provided by
mask and policy.
cpuset_setdomain() attempts to set the mask and policy for the object
specified by level, which and id to the values in mask and policy.
ALLOCATION POLICIES
Valid policy values are as follows:
DOMAINSET_POLICY_ROUNDROBIN
Memory is allocated on a round-robin basis by cycling through each
domain in mask.
in the mask. If memory is unavailable the domains listed in the
parent cpuset will be visited in a round-robin order.
RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
The following error codes may be set in errno:
[EINVAL] The level or which argument was not a valid value.
[EINVAL] The mask or policy argument specified when calling
cpuset_setdomain() was not a valid value.
[EDEADLK] The cpuset_setdomain() call would leave a thread
without a valid CPU to run on because the set does not
overlap with the thread's anonymous mask.
[EFAULT] The mask pointer passed was invalid.
[ESRCH] The object specified by the id and which arguments
could not be found.
[ERANGE] The domainsetsize was either preposterously large or
smaller than the kernel set size.
[EPERM] The calling process did not have the credentials
required to complete the operation.
[ECAPMODE] The calling process attempted to act on a process
other than itself, while in capability mode. See
capsicum(4).
SEE ALSO
cpuset(1), cpuset(2), cpuset_getaffinity(2), cpuset_getid(2),
cpuset_setaffinity(2), cpuset_setid(2), capsicum(4), cpuset(9)
HISTORY
The cpuset_getdomain family of system calls first appeared in
FreeBSD 12.0.
AUTHORS
Jeffrey Roberson <jeff@FreeBSD.org>
FreeBSD 14.0-RELEASE-p11 June 18, 2020 FreeBSD 14.0-RELEASE-p11