cpusetAllocQueueDef(3x) cpusetAllocQueueDef(3x)
cpusetAllocQueueDef - allocate a cpuset_QueueDef_t structure
#include <cpuset.h>
cpuset_QueueDef_t *cpusetAllocQueueDef(int count)
The cpusetAllocQueueDef function is used to allocate memory for a
cpuset_QueueDef_t structure. This memory can then be released using the
function cpusetFreeQueueDef(3x).
The count argument indicates the number of CPUs that will be assigned to
the cpuset definition structure. The cpuset_QueueDef_t structure is
defined as follows:
typedef struct {
int flags;
char *permfile;
cpuset_CPUList_t *cpu;
} cpuset_QueueDef_t;
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_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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cpusetAllocQueueDef(3x) cpusetAllocQueueDef(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.
The permfile member is the name of the file that defines the access
permissions for the cpuset queue. The file permissions of filename
referenced by permfile define access to the cpuset. Every time
permissions need to be checked, the current permissions of this file are
used. Thus, it is possible to change the access to a particular cpuset
without having to tear it down and recreate it, simply by changing the
access permissions. Read access to the permfile allows a user to
retrieve information about a cpuset, while execute permission allows the
user to attach a process to the cpuset.
The cpu member is a pointer to a cpuset_CPUList_t structure. The memory
for the cpuset_CPUList_t structure is allocated and released when the
cpuset_QueueDef_t structure is allocated and released (see
cpusetFreeQueueDef(3x)). The cpuset_CPUList_t structure contains the list
of CPUs assigned to the cpuset. The cpuset_CPUList_t structure (defind
in <cpuset.h>) is defined as follows:
typedef struct {
int count;
int *list;
} cpuset_CPUList_t;
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cpusetAllocQueueDef(3x) cpusetAllocQueueDef(3x)
The count member defines the number of CPUs contained in the list.
The list member is the pointer to the list (an allocated array) of the
CPU IDs. The memory for the list array is allocated and released when
the cpuset_CPUList_t structure is allocated and released. The size of
the list is determined by the count argument passed into the function
cpusetAllocQueueDef.
This example creates a cpuset queue using cpusetCreate(3x) and provides
an example of how cpusetAllocQueueDef might be used. The cpuset created
will have access controlled by the file /usr/tmp/mypermfile; it will
contain CPU IDs 4, 8, and 12; and it will be CPU exclusive and memory
exclusive:
cpuset_QueueDef_t *qdef;
char *qname = "myqueue";
/* Alloc queue def for 3 CPU IDs */
qdef = cpusetAllocQueueDef(3);
if (!qdef) {
perror("cpusetAllocQueueDef");
exit(1);
}
/* Define attributes of the cpuset */
qdef->flags = CPUSET_CPU_EXCLUSIVE
| CPUSET_MEMORY_EXCLUSIVE;
qdef->permfile = "/usr/tmp/mypermfile"
qdef->cpu->count = 3;
qdef->cpu->list[0] = 4;
qdef->cpu->list[1] = 8;
qdef->cpu->list[2] = 12;
/* Request that the cpuset be created */
if (!cpusetCreate(qname, qdef)) {
perror("cpusetCreate");
exit(1);
}
cpusetFreeQueueDef(qdef);
cpusetAllocQueueDef is found in the library "libcpuset.so", and will be
loaded if the option -lcpuset is used with cc(1) or ld(1).
cpuset(1), cpusetAllocQueueDef(3x), cpusetFreeQueueDef(3x). cpuset(5).
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cpusetAllocQueueDef(3x) cpusetAllocQueueDef(3x)
DIAGNOSTICS
If successful, cpusetAllocQueueDef returns a pointer to a
cpuset_QueueDef_t structure. If cpusetAllocQueueDef fails, it returns
NULL and errno is set to indicate the error. The possible errno values
include those returned by sbrk(2) and the following:
EINVAL [Toc] [Back]
Invalid argument was supplied. The user must supply a value greater
than or equal to 0.
PPPPaaaaggggeeee 4444 [ Back ]
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