fix: fix mining chunk cache

[JamesPiechota]

https://github.com/ArweaveTeam/arweave-dev/issues/666

[shizzard]

No major problems with the code (didn't test it though)

[shizzard]

These parts of the code are easily extracted into sharp functions like

maybe_update_cache_limit(PartitionCacheLimit, #state{chunk_cache_limit = PartitionCacheLimit} = S0) -> S0;
maybe_update_cache_limit(PartitionCacheLimit, S0) ->
    ...

This will greatly reduce the nesting within a function and reduce function scope.

[JamesPiechota]

Done! 1a8a2ce

[shizzard]

The logic is not clear here.
We're checking if the gc_frequency_ms is defined in the process state, but not checking if the gc_process_ref is set (the actual marker that the timer is set here). So there are a possible scenario where we will have two timers set at the same time.
I would recommend saving the actual timer reference in the state and extract the timer initialization into a separate function. The example may be found in the P3 ledger implementation (handle_continue(?msg_continue_start_shutdown_timer, ...) @ ar_p3_ledger.erl line 431):

• ensure you cancel the existing timer if the timer exists and still running;
• ensure to put the unique marker into timer message (this is already done here);

When hitting the timer message handler, just do the related work and ensure to call the extracted timer initialization function once again, that will do all the needed things.

[JamesPiechota]

Got it - Done! cb46fb0