Why don't most Android devices have swap area as typical OS does?

Question

Does any Android today support swap area which is suppose to boost the performance?

What are the considerations that make most Android devices drop that feature?

Answer 1

For Android or even iOS to practically support non-kernel swapping, three hurdles must be overcome:

1. Space Constraints: Due to the usage of flash memory, as opposed to HDD's, space comes at a relative premium
2. Write Frequency: Flash memory tolerates fewer writes before becoming unreliable (relative to HDD)
3. Communication Throughput: There is poor throughput between main memory and flash memory on mobile devices