Provided by: libnuma-dev_2.0.16-1_amd64 
NAME
numa - NUMA policy library
SYNOPSIS
#include <numa.h>
cc ... -lnuma
int numa_available(void);
int numa_max_possible_node(void);
int numa_num_possible_nodes();
int numa_max_node(void);
int numa_num_configured_nodes();
struct bitmask *numa_get_mems_allowed(void);
int numa_num_configured_cpus(void);
struct bitmask *numa_all_nodes_ptr;
struct bitmask *numa_no_nodes_ptr;
struct bitmask *numa_all_cpus_ptr;
int numa_num_task_cpus();
int numa_num_task_nodes();
int numa_parse_bitmap(char *line , struct bitmask *mask);
struct bitmask *numa_parse_nodestring(const char *string);
struct bitmask *numa_parse_nodestring_all(const char *string);
struct bitmask *numa_parse_cpustring(const char *string);
struct bitmask *numa_parse_cpustring_all(const char *string);
long long numa_node_size(int node, long long*freep);
long long numa_node_size64(int node, long long *freep);
int numa_preferred(void);
int numa_has_preferred_many(void);
struct bitmask *numa_preferred_many(void);
void numa_set_preferred(int node);
void numa_set_preferred_many(struct bitmask *nodemask);
int numa_get_interleave_node(void);
struct bitmask *numa_get_interleave_mask(void);
void numa_set_interleave_mask(struct bitmask *nodemask);
void numa_interleave_memory(void *start, size_t size, struct bitmask *nodemask);
void numa_bind(struct bitmask *nodemask);
void numa_set_localalloc(void);
void numa_set_membind(struct bitmask *nodemask);
void numa_set_membind_balancing(struct bitmask *nodemask);
struct bitmask *numa_get_membind(void);
void *numa_alloc_onnode(size_t size, int node);
void *numa_alloc_local(size_t size);
void *numa_alloc_interleaved(size_t size);
void *numa_alloc_interleaved_subset(size_t size, struct bitmask *nodemask); void
*numa_alloc(size_t size);
void *numa_realloc(void *old_addr, size_t old_size, size_t new_size);
void numa_free(void *start, size_t size);
int numa_run_on_node(int node);
int numa_run_on_node_mask(struct bitmask *nodemask);
int numa_run_on_node_mask_all(struct bitmask *nodemask);
struct bitmask *numa_get_run_node_mask(void);
void numa_tonode_memory(void *start, size_t size, int node);
void numa_tonodemask_memory(void *start, size_t size, struct bitmask *nodemask);
void numa_setlocal_memory(void *start, size_t size);
void numa_police_memory(void *start, size_t size);
void numa_set_bind_policy(int strict);
void numa_set_strict(int strict);
int numa_distance(int node1, int node2);
int numa_sched_getaffinity(pid_t pid, struct bitmask *mask);
int numa_sched_setaffinity(pid_t pid, struct bitmask *mask);
int numa_node_to_cpus(int node, struct bitmask *mask);
void numa_node_to_cpu_update();
int numa_node_of_cpu(int cpu);
struct bitmask *numa_allocate_cpumask();
void numa_free_cpumask();
struct bitmask *numa_allocate_nodemask();
void numa_free_nodemask();
struct bitmask *numa_bitmask_alloc(unsigned int n);
struct bitmask *numa_bitmask_clearall(struct bitmask *bmp);
struct bitmask *numa_bitmask_clearbit(struct bitmask *bmp, unsigned int n);
int numa_bitmask_equal(const struct bitmask *bmp1, const struct bitmask *bmp2);
void numa_bitmask_free(struct bitmask *bmp);
int numa_bitmask_isbitset(const struct bitmask *bmp, unsigned int n);
unsigned int numa_bitmask_nbytes(struct bitmask *bmp);
struct bitmask *numa_bitmask_setall(struct bitmask *bmp);
struct bitmask *numa_bitmask_setbit(struct bitmask *bmp, unsigned int n);
void copy_bitmask_to_nodemask(struct bitmask *bmp, nodemask_t *nodemask)
void copy_nodemask_to_bitmask(nodemask_t *nodemask, struct bitmask *bmp)
void copy_bitmask_to_bitmask(struct bitmask *bmpfrom, struct bitmask *bmpto)
unsigned int numa_bitmask_weight(const struct bitmask *bmp )
int numa_move_pages(int pid, unsigned long count, void **pages, const int *nodes, int
*status, int flags);
int numa_migrate_pages(int pid, struct bitmask *fromnodes, struct bitmask *tonodes);
void numa_error(char *where);
extern int numa_exit_on_error;
extern int numa_exit_on_warn;
void numa_warn(int number, char *where, ...);
DESCRIPTION
The libnuma library offers a simple programming interface to the NUMA (Non Uniform Memory
Access) policy supported by the Linux kernel. On a NUMA architecture some memory areas
have different latency or bandwidth than others.
Available policies are page interleaving (i.e., allocate in a round-robin fashion from
all, or a subset, of the nodes on the system), preferred node allocation (i.e., preferably
allocate on a particular node), local allocation (i.e., allocate on the node on which the
task is currently executing), or allocation only on specific nodes (i.e., allocate on some
subset of the available nodes). It is also possible to bind tasks to specific nodes.
Numa memory allocation policy may be specified as a per-task attribute, that is inherited
by children tasks and processes, or as an attribute of a range of process virtual address
space. Numa memory policies specified for a range of virtual address space are shared by
all tasks in the process. Furthermore, memory policies specified for a range of a shared
memory attached using shmat(2) or mmap(2) from shmfs/hugetlbfs are shared by all processes
that attach to that region. Memory policies for shared disk backed file mappings are
currently ignored.
The default memory allocation policy for tasks and all memory range is local allocation.
This assumes that no ancestor has installed a non-default policy.
For setting a specific policy globally for all memory allocations in a process and its
children it is easiest to start it with the numactl(8) utility. For more finegrained
policy inside an application this library can be used.
All numa memory allocation policy only takes effect when a page is actually faulted into
the address space of a process by accessing it. The numa_alloc_* functions take care of
this automatically.
A node is defined as an area where all memory has the same speed as seen from a particular
CPU. A node can contain multiple CPUs. Caches are ignored for this definition.
Most functions in this library are only concerned about numa nodes and their memory. The
exceptions to this are: numa_node_to_cpus(), numa_node_to_cpu_update(),
numa_node_of_cpu(), numa_bind(), numa_run_on_node(), numa_run_on_node_mask(),
numa_run_on_node_mask_all(), and numa_get_run_node_mask(). These functions deal with the
CPUs associated with numa nodes. See the descriptions below for more information.
Some of these functions accept or return a pointer to struct bitmask. A struct bitmask
controls a bit map of arbitrary length containing a bit representation of nodes. The
predefined variable numa_all_nodes_ptr points to a bit mask that has all available nodes
set; numa_no_nodes_ptr points to the empty set.
Before any other calls in this library can be used numa_available() must be called. If it
returns -1, all other functions in this library are undefined.
numa_max_possible_node() returns the number of the highest possible node in a system. In
other words, the size of a kernel type nodemask_t (in bits) minus 1. This number can be
gotten by calling numa_num_possible_nodes() and subtracting 1.
numa_num_possible_nodes() returns the size of kernel's node mask (kernel type nodemask_t).
In other words, large enough to represent the maximum number of nodes that the kernel can
handle. This will match the kernel's MAX_NUMNODES value. This count is derived from
/proc/self/status, field Mems_allowed.
numa_max_node() returns the highest node number available on the current system. (See the
node numbers in /sys/devices/system/node/ ). Also see numa_num_configured_nodes().
numa_num_configured_nodes() returns the number of memory nodes in the system. This count
includes any nodes that are currently disabled. This count is derived from the node
numbers in /sys/devices/system/node. (Depends on the kernel being configured with /sys
(CONFIG_SYSFS)).
numa_get_mems_allowed() returns the mask of nodes from which the process is allowed to
allocate memory in it's current cpuset context. Any nodes that are not included in the
returned bitmask will be ignored in any of the following libnuma memory policy calls.
numa_num_configured_cpus() returns the number of cpus in the system. This count includes
any cpus that are currently disabled. This count is derived from the cpu numbers in
/sys/devices/system/cpu. If the kernel is configured without /sys (CONFIG_SYSFS=n) then it
falls back to using the number of online cpus.
numa_all_nodes_ptr points to a bitmask that is allocated by the library with bits
representing all nodes on which the calling task may allocate memory. This set may be up
to all nodes on the system, or up to the nodes in the current cpuset. The bitmask is
allocated by a call to numa_allocate_nodemask() using size numa_max_possible_node(). The
set of nodes to record is derived from /proc/self/status, field "Mems_allowed". The user
should not alter this bitmask.
numa_no_nodes_ptr points to a bitmask that is allocated by the library and left all
zeroes. The bitmask is allocated by a call to numa_allocate_nodemask() using size
numa_max_possible_node(). The user should not alter this bitmask.
numa_all_cpus_ptr points to a bitmask that is allocated by the library with bits
representing all cpus on which the calling task may execute. This set may be up to all
cpus on the system, or up to the cpus in the current cpuset. The bitmask is allocated by
a call to numa_allocate_cpumask() using size numa_num_possible_cpus(). The set of cpus to
record is derived from /proc/self/status, field "Cpus_allowed". The user should not alter
this bitmask.
numa_num_task_cpus() returns the number of cpus that the calling task is allowed to use.
This count is derived from the map /proc/self/status, field "Cpus_allowed". Also see the
bitmask numa_all_cpus_ptr.
numa_num_task_nodes() returns the number of nodes on which the calling task is allowed to
allocate memory. This count is derived from the map /proc/self/status, field
"Mems_allowed". Also see the bitmask numa_all_nodes_ptr.
numa_parse_bitmap() parses line , which is a character string such as found in
/sys/devices/system/node/nodeN/cpumap into a bitmask structure. The string contains the
hexadecimal representation of a bit map. The bitmask may be allocated with
numa_allocate_cpumask(). Returns 0 on success. Returns -1 on failure. This function is
probably of little use to a user application, but it is used by libnuma internally.
numa_parse_nodestring() parses a character string list of nodes into a bit mask. The bit
mask is allocated by numa_allocate_nodemask(). The string is a comma-separated list of
node numbers or node ranges. A leading ! can be used to indicate "not" this list (in
other words, all nodes except this list), and a leading + can be used to indicate that the
node numbers in the list are relative to the task's cpuset. The string can be "all" to
specify all ( numa_num_task_nodes() ) nodes. Node numbers are limited by the number in
the system. See numa_max_node() and numa_num_configured_nodes().
Examples: 1-5,7,10 !4-5 +0-3
If the string is of 0 length, bitmask numa_no_nodes_ptr is returned. Returns 0 if the
string is invalid.
numa_parse_nodestring_all() is similar to numa_parse_nodestring , but can parse all
possible nodes, not only current nodeset.
numa_parse_cpustring() parses a character string list of cpus into a bit mask. The bit
mask is allocated by numa_allocate_cpumask(). The string is a comma-separated list of cpu
numbers or cpu ranges. A leading ! can be used to indicate "not" this list (in other
words, all cpus except this list), and a leading + can be used to indicate that the cpu
numbers in the list are relative to the task's cpuset. The string can be "all" to specify
all ( numa_num_task_cpus() ) cpus. Cpu numbers are limited by the number in the system.
See numa_num_task_cpus() and numa_num_configured_cpus().
Examples: 1-5,7,10 !4-5 +0-3
Returns 0 if the string is invalid.
numa_parse_cpustring_all() is similar to numa_parse_cpustring , but can parse all possible
cpus, not only current cpuset.
numa_node_size() returns the memory size of a node. If the argument freep is not NULL, it
used to return the amount of free memory on the node. On error it returns -1.
numa_node_size64() works the same as numa_node_size(). This is useful on 32-bit
architectures with large nodes.
numa_preferred() returns the preferred node of the current task. This is the node on
which the kernel preferably allocates memory, unless some other policy overrides this.
numa_has_preferred_many() Returns > 0 if the system supports multiple preferred nodes.
numa_preferred_many() Returns the current set of preferred nodes. This implies the empty
set when the policy isn't one used for preference (PREFERRED, PREFERRED_MANY, BIND). The
caller is responsible for freeing the mask with numa_bitmask_free().
numa_set_preferred() sets the preferred node for the current task to node. The system
will attempt to allocate memory from the preferred node, but will fall back to other nodes
if no memory is available on the the preferred node. Passing a node of -1 argument
specifies local allocation and is equivalent to calling numa_set_localalloc().
numa_set_preferred_many() sets the preferred set of nodes for the current task to
nodemask. This is similar to numa_set_preferred() with the exception that it utilizes a
different kernel interface to specify multiple preferred nodes. The caller is responsible
for freeing the mask with numa_bitmask_free().
numa_get_interleave_mask() returns the current interleave mask if the task's memory
allocation policy is page interleaved. Otherwise, this function returns an empty mask.
numa_set_interleave_mask() sets the memory interleave mask for the current task to
nodemask. All new memory allocations are page interleaved over all nodes in the
interleave mask. Interleaving can be turned off again by passing an empty mask
(numa_no_nodes). The page interleaving only occurs on the actual page fault that puts a
new page into the current address space. It is also only a hint: the kernel will fall back
to other nodes if no memory is available on the interleave target.
numa_interleave_memory() interleaves size bytes of memory page by page from start on nodes
specified in nodemask. The size argument will be rounded up to a multiple of the system
page size. If nodemask contains nodes that are externally denied to this process, this
call will fail. This is a lower level function to interleave allocated but not yet
faulted in memory. Not yet faulted in means the memory is allocated using mmap(2) or
shmat(2), but has not been accessed by the current process yet. The memory is page
interleaved to all nodes specified in nodemask. Normally numa_alloc_interleaved() should
be used for private memory instead, but this function is useful to handle shared memory
areas. To be useful the memory area should be several megabytes at least (or tens of
megabytes of hugetlbfs mappings) If the numa_set_strict() flag is true then the operation
will cause a numa_error if there were already pages in the mapping that do not follow the
policy.
numa_bind() binds the current task and its children to the nodes specified in nodemask.
They will only run on the CPUs of the specified nodes and only be able to allocate memory
from them. This function is equivalent to calling numa_run_on_node_mask(nodemask)
followed by numa_set_membind(nodemask). If tasks should be bound to individual CPUs
inside nodes consider using numa_node_to_cpus and the sched_setaffinity(2) syscall.
numa_set_localalloc() sets the memory allocation policy for the calling task to local
allocation. In this mode, the preferred node for memory allocation is effectively the
node where the task is executing at the time of a page allocation.
numa_set_membind() sets the memory allocation mask. The task will only allocate memory
from the nodes set in nodemask. Passing an empty nodemask or a nodemask that contains
nodes other than those in the mask returned by numa_get_mems_allowed() will result in an
error.
numa_set_membind_balancing() sets the memory allocation mask and enable the Linux kernel
NUMA balancing for the task if the feature is supported by the kernel. The task will only
allocate memory from the nodes set in nodemask. Passing an empty nodemask or a nodemask
that contains nodes other than those in the mask returned by numa_get_mems_allowed() will
result in an error.
numa_get_membind() returns the mask of nodes from which memory can currently be allocated.
If the returned mask is equal to numa_all_nodes, then memory allocation is allowed from
all nodes.
numa_alloc_onnode() allocates memory on a specific node. The size argument will be
rounded up to a multiple of the system page size. if the specified node is externally
denied to this process, this call will fail. This function is relatively slow compared to
the malloc(3) family of functions. The memory must be freed with numa_free(). On errors
NULL is returned.
numa_alloc_local() allocates size bytes of memory on the local node. The size argument
will be rounded up to a multiple of the system page size. This function is relatively
slow compared to the malloc(3) family of functions. The memory must be freed with
numa_free(). On errors NULL is returned.
numa_alloc_interleaved() allocates size bytes of memory page interleaved on all nodes.
This function is relatively slow and should only be used for large areas consisting of
multiple pages. The interleaving works at page level and will only show an effect when the
area is large. The allocated memory must be freed with numa_free(). On error, NULL is
returned.
numa_alloc_interleaved_subset() attempts to allocate size bytes of memory page interleaved
on all nodes. The size argument will be rounded up to a multiple of the system page size.
The nodes on which a process is allowed to allocate memory may be constrained externally.
If this is the case, this function may fail. This function is relatively slow compared to
the malloc(3) family of functions and should only be used for large areas consisting of
multiple pages. The interleaving works at page level and will only show an effect when
the area is large. The allocated memory must be freed with numa_free(). On error, NULL
is returned.
numa_alloc() allocates size bytes of memory with the current NUMA policy. The size
argument will be rounded up to a multiple of the system page size. This function is
relatively slow compared to the malloc(3) family of functions. The memory must be freed
with numa_free(). On errors NULL is returned.
numa_realloc() changes the size of the memory area pointed to by old_addr from old_size to
new_size. The memory area pointed to by old_addr must have been allocated with one of the
numa_alloc* functions. The new_size will be rounded up to a multiple of the system page
size. The contents of the memory area will be unchanged to the minimum of the old and new
sizes; newly allocated memory will be uninitialized. The memory policy (and node bindings)
associated with the original memory area will be preserved in the resized area. For
example, if the initial area was allocated with a call to numa_alloc_onnode(), then the
new pages (if the area is enlarged) will be allocated on the same node. However, if no
memory policy was set for the original area, then numa_realloc() cannot guarantee that the
new pages will be allocated on the same node. On success, the address of the resized area
is returned (which might be different from that of the initial area), otherwise NULL is
returned and errno is set to indicate the error. The pointer returned by numa_realloc() is
suitable for passing to numa_free().
numa_free() frees size bytes of memory starting at start, allocated by the numa_alloc_*
functions above. The size argument will be rounded up to a multiple of the system page
size.
numa_run_on_node() runs the current task and its children on a specific node. They will
not migrate to CPUs of other nodes until the node affinity is reset with a new call to
numa_run_on_node_mask(). Passing -1 permits the kernel to schedule on all nodes again.
On success, 0 is returned; on error -1 is returned, and errno is set to indicate the
error.
numa_run_on_node_mask() runs the current task and its children only on nodes specified in
nodemask. They will not migrate to CPUs of other nodes until the node affinity is reset
with a new call to numa_run_on_node_mask() or numa_run_on_node(). Passing numa_all_nodes
permits the kernel to schedule on all nodes again. On success, 0 is returned; on error -1
is returned, and errno is set to indicate the error.
numa_run_on_node_mask_all() runs the current task and its children only on nodes specified
in nodemask like numa_run_on_node_mask but without any cpuset awareness.
numa_get_run_node_mask() returns a mask of CPUs on which the current task is allowed to
run.
numa_tonode_memory() put memory on a specific node. The constraints described for
numa_interleave_memory() apply here too.
numa_tonodemask_memory() put memory on a specific set of nodes. The constraints described
for numa_interleave_memory() apply here too.
numa_setlocal_memory() locates memory on the current node. The constraints described for
numa_interleave_memory() apply here too.
numa_police_memory() locates memory with the current NUMA policy. The constraints
described for numa_interleave_memory() apply here too.
numa_distance() reports the distance in the machine topology between two nodes. The
factors are a multiple of 10. It returns 0 when the distance cannot be determined. A node
has distance 10 to itself. Reporting the distance requires a Linux kernel version of
2.6.10 or newer.
numa_set_bind_policy() specifies whether calls that bind memory to a specific node should
use the preferred policy or a strict policy. The preferred policy allows the kernel to
allocate memory on other nodes when there isn't enough free on the target node. strict
will fail the allocation in that case. Setting the argument to specifies strict, 0
preferred. Note that specifying more than one node non strict may only use the first node
in some kernel versions.
numa_set_strict() sets a flag that says whether the functions allocating on specific nodes
should use use a strict policy. Strict means the allocation will fail if the memory cannot
be allocated on the target node. Default operation is to fall back to other nodes. This
doesn't apply to interleave and default.
numa_get_interleave_node() is used by libnuma internally. It is probably not useful for
user applications. It uses the MPOL_F_NODE flag of the get_mempolicy system call, which
is not intended for application use (its operation may change or be removed altogether in
future kernel versions). See get_mempolicy(2).
numa_pagesize() returns the number of bytes in page. This function is simply a fast
alternative to repeated calls to the getpagesize system call. See getpagesize(2).
numa_sched_getaffinity() retrieves a bitmask of the cpus on which a task may run. The
task is specified by pid. Returns the return value of the sched_getaffinity system call.
See sched_getaffinity(2). The bitmask must be at least the size of the kernel's cpu mask
structure. Use numa_allocate_cpumask() to allocate it. Test the bits in the mask by
calling numa_bitmask_isbitset().
numa_sched_setaffinity() sets a task's allowed cpu's to those cpu's specified in mask.
The task is specified by pid. Returns the return value of the sched_setaffinity system
call. See sched_setaffinity(2). You may allocate the bitmask with
numa_allocate_cpumask(). Or the bitmask may be smaller than the kernel's cpu mask
structure. For example, call numa_bitmask_alloc() using a maximum number of cpus from
numa_num_configured_cpus(). Set the bits in the mask by calling numa_bitmask_setbit().
numa_node_to_cpus() converts a node number to a bitmask of CPUs. The user must pass a
bitmask structure with a mask buffer long enough to represent all possible cpu's. Use
numa_allocate_cpumask() to create it. If the bitmask is not long enough errno will be set
to ERANGE and -1 returned. On success 0 is returned.
numa_node_to_cpu_update() Mark cpus bitmask of all nodes stale, then get the latest
bitmask by calling numa_node_to_cpus() This allows to update the libnuma state after a CPU
hotplug event. The application is in charge of detecting CPU hotplug events.
numa_node_of_cpu() returns the node that a cpu belongs to. If the user supplies an invalid
cpu errno will be set to EINVAL and -1 will be returned.
numa_allocate_cpumask () returns a bitmask of a size equal to the kernel's cpu mask
(kernel type cpumask_t). In other words, large enough to represent NR_CPUS cpus. This
number of cpus can be gotten by calling numa_num_possible_cpus(). The bitmask is zero-
filled.
numa_free_cpumask frees a cpumask previously allocate by numa_allocate_cpumask.
numa_allocate_nodemask() returns a bitmask of a size equal to the kernel's node mask
(kernel type nodemask_t). In other words, large enough to represent MAX_NUMNODES nodes.
This number of nodes can be gotten by calling numa_num_possible_nodes(). The bitmask is
zero-filled.
numa_free_nodemask() frees a nodemask previous allocated by numa_allocate_nodemask().
numa_bitmask_alloc() allocates a bitmask structure and its associated bit mask. The
memory allocated for the bit mask contains enough words (type unsigned long) to contain n
bits. The bit mask is zero-filled. The bitmask structure points to the bit mask and
contains the n value.
numa_bitmask_clearall() sets all bits in the bit mask to 0. The bitmask structure points
to the bit mask and contains its size ( bmp ->size). The value of bmp is always returned.
Note that numa_bitmask_alloc() creates a zero-filled bit mask.
numa_bitmask_clearbit() sets a specified bit in a bit mask to 0. Nothing is done if the n
value is greater than the size of the bitmask (and no error is returned). The value of bmp
is always returned.
numa_bitmask_equal() returns 1 if two bitmasks are equal. It returns 0 if they are not
equal. If the bitmask structures control bit masks of different sizes, the "missing"
trailing bits of the smaller bit mask are considered to be 0.
numa_bitmask_free() deallocates the memory of both the bitmask structure pointed to by bmp
and the bit mask. It is an error to attempt to free this bitmask twice.
numa_bitmask_isbitset() returns the value of a specified bit in a bit mask. If the n
value is greater than the size of the bit map, 0 is returned.
numa_bitmask_nbytes() returns the size (in bytes) of the bit mask controlled by bmp. The
bit masks are always full words (type unsigned long), and the returned size is the actual
size of all those words.
numa_bitmask_setall() sets all bits in the bit mask to 1. The bitmask structure points to
the bit mask and contains its size ( bmp ->size). The value of bmp is always returned.
numa_bitmask_setbit() sets a specified bit in a bit mask to 1. Nothing is done if n is
greater than the size of the bitmask (and no error is returned). The value of bmp is
always returned.
copy_bitmask_to_nodemask() copies the body (the bit map itself) of the bitmask structure
pointed to by bmp to the nodemask_t structure pointed to by the nodemask pointer. If the
two areas differ in size, the copy is truncated to the size of the receiving field or
zero-filled.
copy_nodemask_to_bitmask() copies the nodemask_t structure pointed to by the nodemask
pointer to the body (the bit map itself) of the bitmask structure pointed to by the bmp
pointer. If the two areas differ in size, the copy is truncated to the size of the
receiving field or zero-filled.
copy_bitmask_to_bitmask() copies the body (the bit map itself) of the bitmask structure
pointed to by the bmpfrom pointer to the body of the bitmask structure pointed to by the
bmpto pointer. If the two areas differ in size, the copy is truncated to the size of the
receiving field or zero-filled.
numa_bitmask_weight() returns a count of the bits that are set in the body of the bitmask
pointed to by the bmp argument.
numa_move_pages() moves a list of pages in the address space of the currently executing or
current process. It simply uses the move_pages system call.
pid - ID of task. If not valid, use the current task.
count - Number of pages.
pages - List of pages to move.
nodes - List of nodes to which pages can be moved.
status - Field to which status is to be returned.
flags - MPOL_MF_MOVE or MPOL_MF_MOVE_ALL
See move_pages(2).
numa_migrate_pages() simply uses the migrate_pages system call to cause the pages of the
calling task, or a specified task, to be migated from one set of nodes to another. See
migrate_pages(2). The bit masks representing the nodes should be allocated with
numa_allocate_nodemask() , or with numa_bitmask_alloc() using an n value returned from
numa_num_possible_nodes(). A task's current node set can be gotten by calling
numa_get_membind(). Bits in the tonodes mask can be set by calls to
numa_bitmask_setbit().
numa_error() is a libnuma internal function that can be overridden by the user program.
This function is called with a char * argument when a libnuma function fails. Overriding
the library internal definition makes it possible to specify a different error handling
strategy when a libnuma function fails. It does not affect numa_available(). The
numa_error() function defined in libnuma prints an error on stderr and terminates the
program if numa_exit_on_error is set to a non-zero value. The default value of
numa_exit_on_error is zero.
numa_warn() is a libnuma internal function that can be also overridden by the user
program. It is called to warn the user when a libnuma function encounters a non-fatal
error. The default implementation prints a warning to stderr. The first argument is a
unique number identifying each warning. After that there is a printf(3)-style format
string and a variable number of arguments. numa_warn exits the program when
numa_exit_on_warn is set to a non-zero value. The default value of numa_exit_on_warn is
zero.
Compatibility with libnuma version 1
Binaries that were compiled for libnuma version 1 need not be re-compiled to run with
libnuma version 2.
Source codes written for libnuma version 1 may be re-compiled without change with version
2 installed. To do so, in the code's Makefile add this option to CFLAGS:
-DNUMA_VERSION1_COMPATIBILITY
THREAD SAFETY
numa_set_bind_policy and numa_exit_on_error are process global. The other calls are thread
safe.
COPYRIGHT
Copyright 2002, 2004, 2007, 2008 Andi Kleen, SuSE Labs. libnuma is under the GNU Lesser
General Public License, v2.1.
SEE ALSO
get_mempolicy(2), set_mempolicy(2), getpagesize(2), mbind(2), mmap(2), shmat(2),
numactl(8), sched_getaffinity(2) sched_setaffinity(2) move_pages(2) migrate_pages(2)