trusty (2) migrate_pages.2.gz

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 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).

       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),
       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/.