A method includes defining a first mapping, which translates between logical addresses and physical storage locations in a memory with a first mapping unit size, for accessing the memory by a first processing unit. A second mapping is defined, which translates between the logical addresses and the physical storage locations with a second mapping unit size that is different from the first mapping unit size, for accessing the memory by a second processing unit. Data is exchanged between the first and second processing units via the memory, while accessing the memory by the first processing unit using the first mapping and by the second processing unit using the second mapping.