[heavenlyhash]

I suspect that constant factor memory usage should go hand in hand with the criticality of constant factor cpu usage.

If a constant time cpu algorithm was not also constant factor memory, then the timing of cache misses (or gc, alike) would certainly be subject to side channel attacks.

If constant factor memory usage is attained, I cannot easily think of a way that a garbage collector could cause an interference that leaks information. (Though by all means, one ought think harder than I have.)