MIGRATE_PAGES(2)                                    Linux Programmer's Manual                                   MIGRATE_PAGES(2)



NAME
       migrate_pages - move all pages in a process to another set of nodes

SYNOPSIS
       #include <numaif.h>

       long migrate_pages(int pid, unsigned long maxnode,
                          const unsigned long * old_nodes,
                          const unsigned long * new_nodes);

       Link with -lnuma.

DESCRIPTION
       migrate_pages()  moves  all pages of the process pid that 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 old_nodes during the migration to new_nodes.

       The  old_nodes  and  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 maxnode argument is the maximum node number in the bit mask plus one (this is the same as
       in mbind(2), but different from select(2))

       The pid argument is the ID of the process whose pages are to be moved.  To move pages in another process, the caller must
       be  privileged  (CAP_SYS_NICE)  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 only be moved if the initiating process has the CAP_SYS_NICE privilege.

RETURN VALUE
       On success migrate_pages() returns zero.  On error, it returns -1, and sets errno to indicate the error.

ERRORS
       EPERM  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.

       ESRCH  No process matching pid could be found.

VERSIONS
       The migrate_pages() system call first appeared on Linux in version 2.6.16.

CONFORMING TO
       This system call is Linux-specific.

NOTES
       For information on library support, see numa(7).

       Use  get_mempolicy(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 mbind(2)) and/or the specified process (see set_mempolicy(2)).  That is, memory policy does not  constrain
       the destination nodes used by migrate_pages().

       The <numaif.h> header is not included with glibc, but requires installing libnuma-devel or a similar package.

SEE ALSO
       get_mempolicy(2), mbind(2), set_mempolicy(2), numa(3), numa_maps(5), cpuset(7), numa(7), migratepages(8), numa_stat(8)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2010-06-11                                           MIGRATE_PAGES(2)