@millihertz @paoloredaelli Do these modern GCs also mix in arena allocation? You enter a code block, we statically know some data that will never escape the block and we know its upper bound size, so an instance of the code block gets its own arena of X pages and we just throw away the arena when we exit the block?

Hmm, that sounds a lot like stack allocation. If nothing escapes, is there ever a reason not to use stack allocation? Maybe if the data is huge?