Remove unused fields from Bank (backport #22491) (#22630)

* Remove unused fields from Bank (#22491)

(cherry picked from commit 9977396d8f)

# Conflicts:
#	runtime/src/serde_snapshot/future.rs

* fixup the backport

Co-authored-by: Brooks Prumo <brooks@solana.com>

runtime/src/bank.rs

@@ -864,8 +864,6 @@ pub(crate) struct BankFieldsToDeserialize {
     pub(crate) ns_per_slot: u128,
     pub(crate) genesis_creation_time: UnixTimestamp,
     pub(crate) slots_per_year: f64,
-    #[allow(dead_code)]
-    pub(crate) unused: u64,
     pub(crate) slot: Slot,
     pub(crate) epoch: Epoch,
     pub(crate) block_height: u64,
@@ -904,7 +902,6 @@ pub(crate) struct BankFieldsToSerialize<'a> {
     pub(crate) ns_per_slot: u128,
     pub(crate) genesis_creation_time: UnixTimestamp,
     pub(crate) slots_per_year: f64,
-    pub(crate) unused: u64,
     pub(crate) slot: Slot,
     pub(crate) epoch: Epoch,
     pub(crate) block_height: u64,
@@ -943,7 +940,6 @@ impl PartialEq for Bank {
             && self.ns_per_slot == other.ns_per_slot
             && self.genesis_creation_time == other.genesis_creation_time
             && self.slots_per_year == other.slots_per_year
-            && self.unused == other.unused
             && self.slot == other.slot
             && self.epoch == other.epoch
             && self.block_height == other.block_height
@@ -1095,9 +1091,6 @@ pub struct Bank {
     /// The number of slots per year, used for inflation
     slots_per_year: f64,
 
-    /// Unused
-    unused: u64,
-
     /// Bank slot (i.e. block)
     slot: Slot,
 
@@ -1300,7 +1293,6 @@ impl Bank {
             ns_per_slot: u128::default(),
             genesis_creation_time: UnixTimestamp::default(),
             slots_per_year: f64::default(),
-            unused: u64::default(),
             slot: Slot::default(),
             bank_id: BankId::default(),
             epoch: Epoch::default(),
@@ -1531,7 +1523,6 @@ impl Bank {
             ticks_per_slot: parent.ticks_per_slot,
             ns_per_slot: parent.ns_per_slot,
             genesis_creation_time: parent.genesis_creation_time,
-            unused: parent.unused,
             slots_per_year: parent.slots_per_year,
             epoch_schedule,
             collected_rent: AtomicU64::new(0),
@@ -1738,7 +1729,6 @@ impl Bank {
             ns_per_slot: fields.ns_per_slot,
             genesis_creation_time: fields.genesis_creation_time,
             slots_per_year: fields.slots_per_year,
-            unused: genesis_config.unused,
             slot: fields.slot,
             bank_id: 0,
             epoch: fields.epoch,
@@ -1798,7 +1788,6 @@ impl Bank {
                 * genesis_config.ticks_per_slot as u128
         );
         assert_eq!(bank.genesis_creation_time, genesis_config.creation_time);
-        assert_eq!(bank.unused, genesis_config.unused);
         assert_eq!(bank.max_tick_height, (bank.slot + 1) * bank.ticks_per_slot);
         assert_eq!(
             bank.slots_per_year,
@@ -1843,7 +1832,6 @@ impl Bank {
             ns_per_slot: self.ns_per_slot,
             genesis_creation_time: self.genesis_creation_time,
             slots_per_year: self.slots_per_year,
-            unused: self.unused,
             slot: self.slot,
             epoch: self.epoch,
             block_height: self.block_height,
@@ -1980,11 +1968,6 @@ impl Bank {
         )
     }
 
-    /// Unused conversion
-    pub fn get_unused_from_slot(rooted_slot: Slot, unused: u64) -> u64 {
-        (rooted_slot + (unused - 1)) / unused
-    }
-
     pub fn clock(&self) -> sysvar::clock::Clock {
         from_account(&self.get_account(&sysvar::clock::id()).unwrap_or_default())
             .unwrap_or_default()
@@ -2910,7 +2893,6 @@ impl Bank {
         self.ticks_per_slot = genesis_config.ticks_per_slot();
         self.ns_per_slot = genesis_config.ns_per_slot();
         self.genesis_creation_time = genesis_config.creation_time;
-        self.unused = genesis_config.unused;
         self.max_tick_height = (self.slot + 1) * self.ticks_per_slot;
         self.slots_per_year = genesis_config.slots_per_year();
 

runtime/src/serde_snapshot/future.rs

@@ -63,6 +63,7 @@ pub(crate) struct DeserializableVersionedBank {
     pub(crate) ns_per_slot: u128,
     pub(crate) genesis_creation_time: UnixTimestamp,
     pub(crate) slots_per_year: f64,
+    #[allow(dead_code)]
     pub(crate) unused: u64,
     pub(crate) slot: Slot,
     pub(crate) epoch: Epoch,
@@ -101,7 +102,6 @@ impl From<DeserializableVersionedBank> for BankFieldsToDeserialize {
             ns_per_slot: dvb.ns_per_slot,
             genesis_creation_time: dvb.genesis_creation_time,
             slots_per_year: dvb.slots_per_year,
-            unused: dvb.unused,
             slot: dvb.slot,
             epoch: dvb.epoch,
             block_height: dvb.block_height,
@@ -160,9 +160,6 @@ pub(crate) struct SerializableVersionedBank<'a> {
 
 impl<'a> From<crate::bank::BankFieldsToSerialize<'a>> for SerializableVersionedBank<'a> {
     fn from(rhs: crate::bank::BankFieldsToSerialize<'a>) -> Self {
-        fn new<T: Default>() -> T {
-            T::default()
-        }
         Self {
             blockhash_queue: rhs.blockhash_queue,
             ancestors: rhs.ancestors,
@@ -180,7 +177,7 @@ impl<'a> From<crate::bank::BankFieldsToSerialize<'a>> for SerializableVersionedB
             ns_per_slot: rhs.ns_per_slot,
             genesis_creation_time: rhs.genesis_creation_time,
             slots_per_year: rhs.slots_per_year,
-            unused: rhs.unused,
+            unused: u64::default(),
             slot: rhs.slot,
             epoch: rhs.epoch,
             block_height: rhs.block_height,
@@ -193,7 +190,7 @@ impl<'a> From<crate::bank::BankFieldsToSerialize<'a>> for SerializableVersionedB
             epoch_schedule: rhs.epoch_schedule,
             inflation: rhs.inflation,
             stakes: rhs.stakes,
-            unused_accounts: new(),
+            unused_accounts: UnusedAccounts::default(),
             epoch_stakes: rhs.epoch_stakes,
             is_delta: rhs.is_delta,
         }