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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 3.27 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/.