migrate_pages(2)

1MIGRATE_PAGES(2)           Linux Programmer's Manual          MIGRATE_PAGES(2)
2
3
4

NAME

6       migrate_pages - move all pages in a process to another set of nodes
7

SYNOPSIS

9       #include <numaif.h>
10
11       long migrate_pages(int pid, unsigned long maxnode,
12                          const unsigned long *old_nodes,
13                          const unsigned long *new_nodes);
14
15       Link with -lnuma.
16

DESCRIPTION

18       migrate_pages()  attempts to move all pages of the process pid that are
19       in memory nodes old_nodes to the memory nodes in new_nodes.  Pages  not
20       located  in any node in old_nodes will not be migrated.  As far as pos‐
21       sible, the kernel maintains the relative topology  relationship  inside
22       old_nodes during the migration to new_nodes.
23
24       The old_nodes and new_nodes arguments are pointers to bit masks of node
25       numbers, with up to maxnode bits in each mask.  These masks  are  main‐
26       tained  as  arrays of unsigned long integers (in the last long integer,
27       the bits beyond those specified by maxnode are ignored).   The  maxnode
28       argument  is  the maximum node number in the bit mask plus one (this is
29       the same as in mbind(2), but different from select(2)).
30
31       The pid argument is the ID of the process whose pages are to be  moved.
32       To  move  pages  in  another  process,  the  caller  must be privileged
33       (CAP_SYS_NICE) or the real or effective user ID of the calling  process
34       must match the real or saved-set user ID of the target process.  If pid
35       is 0, then migrate_pages() moves pages of the calling process.
36
37       Pages shared with another process will be moved only if the  initiating
38       process has the CAP_SYS_NICE privilege.
39

RETURN VALUE

41       On  success  migrate_pages() returns the number of pages that could not
42       be moved (i.e., a return of zero means that all pages were successfully
43       moved).  On error, it returns -1, and sets errno to indicate the error.
44

ERRORS

46       EPERM  Insufficient  privilege  (CAP_SYS_NICE)  to  move  pages  of the
47              process   specified   by   pid,   or   insufficient    privilege
48              (CAP_SYS_NICE) to access the specified target nodes.
49
50       ESRCH  No process matching pid could be found.
51

VERSIONS

53       The  migrate_pages()  system  call  first  appeared on Linux in version
54       2.6.16.
55

CONFORMING TO

57       This system call is Linux-specific.
58

NOTES

60       For information on library support, see numa(7).
61
62       Use get_mempolicy(2) with the MPOL_F_MEMS_ALLOWED flag  to  obtain  the
63       set  of  nodes  that are allowed by the calling process's cpuset.  Note
64       that this information is subject to change at any  time  by  manual  or
65       automatic reconfiguration of the cpuset.
66
67       Use  of  migrate_pages() may result in pages whose location (node) vio‐
68       lates the memory policy established for the  specified  addresses  (see
69       mbind(2))  and/or  the  specified process (see set_mempolicy(2)).  That
70       is, memory policy does not constrain  the  destination  nodes  used  by
71       migrate_pages().
72
73       The  <numaif.h>  header  is  not  included  with  glibc,  but  requires
74       installing libnuma-devel or a similar package.
75

COLOPHON

83       This  page  is  part of release 3.53 of the Linux man-pages project.  A
84       description of the project, and information about reporting  bugs,  can
85       be found at http://www.kernel.org/doc/man-pages/.
86
87
88
89Linux                             2012-08-01                  MIGRATE_PAGES(2)