|CPUSET_GETDOMAIN(2)||System Calls Manual||CPUSET_GETDOMAIN(2)|
LIBRARY¶Standard C Library (libc, -lc)
which, id_t id,
which, id_t id,
const domainset_t *mask,
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 effect 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
Masks of type domainset_t are composed using
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
The supplied mask should have a size of
setsize bytes. This size is usually provided by
sizeof(mask) which is ultimately determined
by the value of
DOMAINSET_SETSIZE as defined in
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
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:
- Memory is allocated on a round-robin basis by cycling through each domain in mask.
- Memory is allocated on the domain local to the CPU the requesting thread is running on. Failure to allocate from this domain will fallback to round-robin.
- Memory is allocated preferentially from the single domain specified 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:
- The level or which argument was not a valid value.
- The mask or policy argument
specified when calling
cpuset_setdomain() was not a valid value.
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.
- The mask pointer passed was invalid.
- The object specified by the id and which arguments could not be found.
- The domainsetsize was either preposterously large or smaller than the kernel set size.
- The calling process did not have the credentials required to complete the operation.
- The calling process attempted to act on a process other than itself, while in capability mode. See capsicum(4).
SEE ALSO¶capsicum(4), cpuset(1), cpuset(2), cpuset_getid(2), cpuset_setid(2), cpuset_getaffinity(2), cpuset_setaffinity(2), cpuset(9)
cpuset_getdomainfamily of system calls first appeared in FreeBSD 12.0.
AUTHORS¶Jeffrey Roberson <jeff@FreeBSD.org>
|March 19, 2018||Linux 4.19.0-10-amd64|