migrate_pages


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()  attempts to move 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 pos-
       sible, 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  main-
       tained  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 be moved only if the  initiating
       process has the CAP_SYS_NICE privilege.

RETURN VALUE
       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.

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).
       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), numastat(8)

       Documentation/vm/page_migration in the Linux kernel source tree

COLOPHON
       This  page  is  part of release 3.54 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                             2012-08-01                  MIGRATE_PAGES(2)
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