v1.1: Eager rent collection (#10028)

* Introduce eager rent collection (#9527)

* Switch AccountsIndex.account_maps from HashMap to BTreeMap

* Introduce eager rent collection

* Start to add tests

* Avoid too short eager rent collection cycles

* Add more tests

* Add more tests...

* Refacotr!!!!!!

* Refactoring follow up

* More tiny cleanups

* Don't rewrite 0-lamport accounts to be deterministic

* Refactor a bit

* Do hard fork, restore tests, and perf. mitigation

* Fix build...

* Refactor and add switch over for testnet (TdS)

* Use to_be_bytes

* cleanup

* More tiny cleanup

* Rebase cleanup

* Set Bank::genesis_hash when resuming from snapshot

* Reorder fns and clean ups

* Better naming and commenting

* Yet more naming clarifications

* Make prefix width strictly uniform for 2-base partition_count

* Fix typo...

* Revert cluster-dependent gate

* kick ci?

* kick ci?

* kick ci?

(cherry picked from commit 1eb40c3fe0)

# Conflicts:
#	core/tests/bank_forks.rs
#	ledger/src/bank_forks_utils.rs
#	ledger/src/snapshot_utils.rs
#	runtime/src/bank.rs

* Fix merge conflicts

* Add gating

* Add Danger comment...

* Delay activation epoch

* Add gating for stable as well

* fmt...

* fmt!!!!

sdk/src/clock.rs

@@ -85,6 +85,12 @@ pub type Segment = u64;
 ///  some number of Slots.
 pub type Epoch = u64;
 
+/// SlotIndex is an index to the slots of a epoch
+pub type SlotIndex = u64;
+
+/// SlotCount is the number of slots in a epoch
+pub type SlotCount = u64;
+
 /// UnixTimestamp is an approximate measure of real-world time,
 /// expressed as Unix time (ie. seconds since the Unix epoch)
 pub type UnixTimestamp = i64;

sdk/src/hash.rs

@@ -78,6 +78,14 @@ impl Hash {
     pub fn new(hash_slice: &[u8]) -> Self {
         Hash(<[u8; HASH_BYTES]>::try_from(hash_slice).unwrap())
     }
+
+    pub const fn new_from_array(hash_array: [u8; HASH_BYTES]) -> Self {
+        Self(hash_array)
+    }
+
+    pub fn to_bytes(self) -> [u8; HASH_BYTES] {
+        self.0
+    }
 }
 
 /// Return a Sha256 hash for the given data.