selftests: vm: add tests for lock on fault

Test the mmap() flag, and the mlockall() flag.  These tests ensure that
pages are not faulted in until they are accessed, that the pages are
unevictable once faulted in, and that VMA splitting and merging works with
the new VM flag.  The second test ensures that mlock limits are respected.
 Note that the limit test needs to be run a normal user.

Also add tests to use the new mlock2 family of system calls.

[[email protected]: : Fix mlock2-tests for 32-bit architectures]
[[email protected]: ensure the mlock2 syscall number can be found]
[[email protected]: use the right arguments for main()]
Signed-off-by: Eric B Munson <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

tools/testing/selftests/vm/Makefile

@@ -5,6 +5,8 @@ BINARIES = compaction_test
 BINARIES += hugepage-mmap
 BINARIES += hugepage-shm
 BINARIES += map_hugetlb
+BINARIES += mlock2-tests
+BINARIES += on-fault-limit
 BINARIES += thuge-gen
 BINARIES += transhuge-stress
 BINARIES += userfaultfd