migrate_pages - move all pages in a process to another set of nodes
long migrate_pages(int pid, unsigned long maxnode,
const unsigned long *old_nodes,
const unsigned long *new_nodes);
Link with -lnuma
() attempts to move all pages of the process pid
are in memory nodes old_nodes
to the memory nodes in new_nodes
Pages not located in any node in old_nodes
will not be migrated. As far
as possible, the kernel maintains the relative topology relationship inside
during the migration to new_nodes
arguments are pointers to bit masks of
node numbers, with up to maxnode
bits in each mask. These masks are
maintained as arrays of unsigned long
integers (in the last long
integer, the bits beyond those specified by maxnode
are ignored). The
argument is the maximum node number in the bit mask plus one
(this is the same as in mbind
(2), but different from select
argument is the ID of the process whose pages are to be moved. To
move pages in another process, the caller must be privileged
) or the real or effective user ID of the calling process
must match the real or saved-set user ID of the target process. If pid
is 0, then migrate_pages
() moves pages of the calling process.
Pages shared with another process will be moved only if the initiating process
has the CAP_SYS_NICE
On success migrate_pages
() returns the number of pages that could not be
moved (i.e., a return of zero means that all pages were successfully moved).
On error, it returns -1, and sets errno
to indicate the error.
- Part or all of the memory range specified by
old_nodes/new_nodes and maxnode points outside your
accessible address space.
- The value specified by maxnode exceeds a kernel-imposed limit. Or,
old_nodes or new_nodes specifies one or more node IDs that
are greater than the maximum supported node ID. Or, none of the node IDs
specified by new_nodes are on-line and allowed by the process's
current cpuset context, or none of the specified nodes contain
- Insufficient privilege (CAP_SYS_NICE) to move pages of the process
specified by pid, or insufficient privilege (CAP_SYS_NICE)
to access the specified target nodes.
- No process matching pid could be found.
() system call first appeared on Linux in version
This system call is Linux-specific.
For information on library support, see numa
(2) with the MPOL_F_MEMS_ALLOWED
flag to obtain
the set of nodes that are allowed by the calling process's cpuset. Note that
this information is subject to change at any time by manual or automatic
reconfiguration of the cpuset.
Use of migrate_pages
() may result in pages whose location (node) violates
the memory policy established for the specified addresses (see
(2)) and/or the specified process (see set_mempolicy
That is, memory policy does not constrain the destination nodes used by
header is not included with glibc, but requires
or a similar package.
in the Linux kernel source tree