cpusetSetFlags(3x)cpusetSetFlags(3x)NAMEcpusetSetFlags - Set the mask of flags for a cpuset
SYNOPSIS
#include <cpuset.h>
int cpusetSetFlags(cpuset_QueueDef_t *qdef, int flags);
DESCRIPTION
The cpusetSetFlags function is used to set the mask of attribute flags to
be used when creating a cpuset. The argument qdef is a pointer to a
structure allocated by a call to cpusetAllocQueueDef(3x), and the mask of
attribute flags will be set in this structure.
The referenced qdef structure will later be used as an argument to the
function cpusetCreate(3x) when creating the cpuset.
The flags member is used to specify various control options for the
cpuset queue. It is formed by OR-ing together zero or more of the
following values:
CPUSET_CPU_EXCLUSIVE
Defines a cpuset to be restricted. Only threads attached to the
cpuset queue (descendents of an attached thread inherit the
attachement) may execute on the CPUs contained in the cpuset.
CPUSET_EXPLICIT
By default, if a CPU is part of a cpuset the memory on the node
where the CPU is located is also part of the cpuset. This flag
overrides the default behavior. If this directive is present, the
nodes with memory to be included in the cpuset must be specified
using the MEM or NODE directives.
CPUSET_MEMORY_LOCAL
Threads assigned to the cpuset will attempt to assign memory only
from nodes within the cpuset. Assignment of memory from outside
the cpuset will occur only if no free memory is available from
within the cpuset. No restrictions are made on memory assignment
to threads running outside the cpuset.
CPUSET_MEMORY_EXCLUSIVE
Threads assigned to the cpuset will attempt to assign memory only
from nodes within the cpuset. Assignment of memory from outside
the cpuset will occur only if no free memory is available from
within the cpuset. Threads not assigned to the cpuset will not
use memory from within the cpuset unless no memory outside the
cpuset is available. If, at the time a cpuset is created, memory
is already assigned to threads that are already running, no
attempt will be made to explicitly move this memory. If page
migration is enabled, the pages will be migrated when the system
detects that most references to the pages are non-local.
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cpusetSetFlags(3x)cpusetSetFlags(3x)
CPUSET_MEMORY_KERNEL_AVOID
The kernel should attempt to avoid allocating memory from nodes
contained in this cpuset. If kernel memory requests cannot be
satisfied from outside this cpuset, this option will be ignored
and allocations will occur from within the cpuset. (This avoidance
currently extends only to keeping buffer cache away from the
protected nodes.)
CPUSET_MEMORY_MANDATORY
The kernel will limit all memory allocations to nodes that are
contained in this cpuset. If memory requests cannot be satisfied,
the allocating process will sleep until memory is available. The
process will be killed if no more memory can be allocated. See
policies below.
CPUSET_POLICY_PAGE
Requires MEMORY_MANDATORY. This is the default policy if no policy
is specified. This policy will cause the kernel to page user pages
to the swap file (see swap(1M)) to free physical memory on the
nodes contained in this cpuset. If swap space is exhausted, the
process will be killed.
CPUSET_POLICY_KILL
Requires MEMORY_MANDATORY. The kernel will attempt to free as much
space as possible from kernel heaps, but will not page user pages
to the swap file. If all physical memory on the nodes contained
in this cpuset are exhausted, the process will be killed.
CPUSET_POLICY_SHARE_WARN
When creating a cpuset, if it is possible for the new cpuset to
share memory on a node with another cpuset the new cpuset will be
created but a warning message will be issued. POLICY_SHARE_WARN
and POLICY_SHARE_FAIL cannot be used together.
CPUSET_POLICY_SHARE_FAIL
When creating a cpuset, if it is possible for the new cpuset to
share memory on a node with another cpuset the new cpuset will
fail to be created and an error message will be issued.
POLICY_SHARE_WARN and POLICY_SHARE_FAIL cannot be used together.
The return value of the function indicates if the function was
successfully executed.
EXAMPLES
This example sets the flags for a new cpuset queue definition
cpuset_QueueDef_t *qdef;
qdef = cpusetAllocQueueDef(numcpus);
/* Set the mask of flags */
if (!cpusetSetFlags(qdef,
CPU_EXCLUSIVE|EXPLICIT
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cpusetSetFlags(3x)cpusetSetFlags(3x)
|MEMORY_MANDATORY)) ) {
perror("cpusetSetFlags");
exit(1);
}
.......
cpusetCreate("set1", qdef);
NOTEScpusetSetFlags is found in the library "libcpuset.so", and will be loaded
if the option -lcpuset is used with cc(1) or ld(1).
SEE ALSOcpuset(1), cpusetAllocQueueDef(3x), cpusetCreate(3x), cpusetSetFlags(3x),
cpuset(5).
DIAGNOSTICS
If successful, cpusetSetFlags returns 1. If cpusetSetFlags fails, it
returns 0 and errno is set to indicate the error.
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