Adaptive Address Space Whitepaper

4. The MAP_GLOBAL and MAP_ADDR32 flags of mmap(2) behave differently

for MPAS and non-MPAS processes.

MAP_GLOBAL MAP_ADDR32 MAP_ADDR32|MAP_GLOBAL

32-bit

MPAS

No effect No effect No effect

32-bit,

non-

MPAS

Goes to 4th

quadrant

No effect

Same as MAP_GLOBAL

64-bit

MPAS

Goes to 6th

Octant

No effect

Same as MAP_GLOBAL

64-bit,

non-

MPAS

Goes to 6th

Octant

Goes to

virtual

address <4GB

Goes to virtual address

between 3GB and 4GB

5. MPAS processes attach shared library text in private address space.

However, the text is still shared with other processes. Hence, breakpoints

cannot be placed in them. To place breakpoints in shared library text,

use chatr +dbg enable.