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()	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 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 the number of pages that could not be moved (i.e., a return of zero means that all pages were success-
       fully 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).

       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)

       Documentation/vm/page_migration in the Linux kernel source tree

COLOPHON

       This page is part of release 3.44 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)