feat(cmc): Increase cycles_limit by 3x. (#3093)

Prices recently increased, and users have started running into the
previous limit.

This is a much simpler alternative to (and mutually exclusive with)
#3087

rs/nns/cmc/src/main.rs

@@ -72,6 +72,11 @@ const MAX_MEMO_LENGTH: usize = 32;
 /// This is the minimum amount needed for creating a canister as of October 2023.
 const CREATE_CANISTER_MIN_CYCLES: u64 = 100_000_000_000;
 
+/// Prior to 2024-12-10, we used 50e15, but legitimate users started running
+/// into this. At that time, prices had recently gone up, so we resolved to
+/// increase this by 3x.
+const DEFAULT_CYCLES_LIMIT: u128 = 150e15 as u128;
+
 thread_local! {
     static STATE: RefCell<Option<State>> = const { RefCell::new(None) };
     static LIMITER_REJECT_COUNT: Cell<u64> = const { Cell::new(0_u64) };
@@ -336,7 +341,7 @@ impl Default for State {
                 ICP_XDR_CONVERSION_RATE_CACHE_SIZE
             ]),
             cycles_per_xdr: DEFAULT_CYCLES_PER_XDR.into(),
-            cycles_limit: 50_000_000_000_000_000u128.into(), // == 50 Pcycles/hour
+            cycles_limit: Cycles::from(DEFAULT_CYCLES_LIMIT),
             limiter: limiter::Limiter::new(resolution, max_age),
             total_cycles_minted: Cycles::zero(),
             blocks_notified: BTreeMap::new(),
@@ -2279,6 +2284,9 @@ fn post_upgrade(maybe_args: Option<CyclesCanisterInitPayload>) {
         new_state.cycles_ledger_canister_id = args.cycles_ledger_canister_id;
     }
 
+    // Delete after release.
+    new_state.cycles_limit = Cycles::new(DEFAULT_CYCLES_LIMIT);
+
     STATE.with(|state| state.replace(Some(new_state)));
 }
 

rs/nns/integration_tests/src/cycles_minting_canister.rs

@@ -1413,41 +1413,44 @@ fn cmc_notify_top_up_invalid() {
 
 #[test]
 fn cmc_notify_top_up_rate_limited() {
-    let account = AccountIdentifier::new(*TEST_USER1_PRINCIPAL, None);
-    let icpts = Tokens::new(1_000, 0).unwrap();
     let state_machine = state_machine_builder_for_nns_tests().build();
+
+    let account = AccountIdentifier::new(*TEST_USER1_PRINCIPAL, None);
+    // The only requirement here is to have sufficient funds. Other than that,
+    // the precise number here does not matter.
+    let balance = Tokens::new(1e6 as u64, 0).unwrap();
     let nns_init_payloads = NnsInitPayloadsBuilder::new()
         .with_test_neurons()
-        .with_ledger_account(account, icpts)
+        .with_ledger_account(account, balance)
         .build();
     setup_nns_canisters(&state_machine, nns_init_payloads);
 
-    // First top-up should succeed since it's 30P - less than the 50P/hr limit.
+    // First top-up should succeed since it's 90P - less than the 150P/hr limit.
     let cycles = notify_top_up(
         &state_machine,
         GOVERNANCE_CANISTER_ID,
-        Tokens::new(300, 0).unwrap(),
+        Tokens::new(900, 0).unwrap(),
     )
     .unwrap();
-    assert_eq!(cycles, Cycles::new(30_000_000_000_000_000u128));
+    assert_eq!(cycles, Cycles::new(90e15 as u128));
 
     // Second top-up should also succeed after 1 hour.
     state_machine.advance_time(Duration::from_secs(4000));
     let cycles = notify_top_up(
         &state_machine,
         GOVERNANCE_CANISTER_ID,
-        Tokens::new(300, 0).unwrap(),
+        Tokens::new(900, 0).unwrap(),
     )
     .unwrap();
-    assert_eq!(cycles, Cycles::new(30_000_000_000_000_000u128));
+    assert_eq!(cycles, Cycles::new(90e15 as u128));
 
-    // Third top-up should fail since the rate limit is 50P cycles per hour, and less than an hour
-    // has passed.
+    // Third top-up should fail since the rate limit is 150e15 cycles per hour,
+    // and less than an hour has passed.
     state_machine.advance_time(Duration::from_secs(3000));
     let error = notify_top_up(
         &state_machine,
         GOVERNANCE_CANISTER_ID,
-        Tokens::new(300, 0).unwrap(),
+        Tokens::new(900, 0).unwrap(),
     )
     .unwrap_err();
     assert_matches!(error, NotifyError::Refunded { reason, .. } if reason.contains("try again later"));