The size of vmalloc area depends from various factors
on boot and could be set to:
1. Default size as determined by VMALLOC_DEFAULT_SIZE macro;
2. One half of the virtual address space not occupied by
modules and fixed mappings;
3. The size provided by user with vmalloc= kernel command
line parameter;
In cases [1] and [2] the vmalloc area base address is aligned
on Region3 table type boundary, while in case [3] in might get
aligned on page boundary.
Limit the waste of page tables and always align vmalloc area
size and base address on segment boundary.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>