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?

runtime/src/accounts.rs

@@ -27,6 +27,7 @@ use solana_sdk::{
 use std::{
     collections::{HashMap, HashSet},
     io::{BufReader, Error as IOError, Read},
+    ops::RangeBounds,
     path::{Path, PathBuf},
     sync::{Arc, Mutex, RwLock},
 };
@@ -455,6 +456,21 @@ impl Accounts {
         }
     }
 
+    fn load_while_filtering<F: Fn(&Account) -> bool>(
+        collector: &mut Vec<(Pubkey, Account)>,
+        option: Option<(&Pubkey, Account, Slot)>,
+        filter: F,
+    ) {
+        if let Some(data) = option
+            // Don't ever load zero lamport accounts into runtime because
+            // the existence of zero-lamport accounts are never deterministic!!
+            .filter(|(_, account, _)| account.lamports > 0 && filter(account))
+            .map(|(pubkey, account, _slot)| (*pubkey, account))
+        {
+            collector.push(data)
+        }
+    }
+
     pub fn load_by_program(
         &self,
         ancestors: &Ancestors,
@@ -463,15 +479,23 @@ impl Accounts {
         self.accounts_db.scan_accounts(
             ancestors,
             |collector: &mut Vec<(Pubkey, Account)>, option| {
-                if let Some(data) = option
-                    .filter(|(_, account, _)| {
-                        (program_id.is_none() || Some(&account.owner) == program_id)
-                            && account.lamports != 0
-                    })
-                    .map(|(pubkey, account, _slot)| (*pubkey, account))
-                {
-                    collector.push(data)
-                }
+                Self::load_while_filtering(collector, option, |account| {
+                    program_id.is_none() || Some(&account.owner) == program_id
+                })
+            },
+        )
+    }
+
+    pub fn load_to_collect_rent_eagerly<R: RangeBounds<Pubkey>>(
+        &self,
+        ancestors: &Ancestors,
+        range: R,
+    ) -> Vec<(Pubkey, Account)> {
+        self.accounts_db.range_scan_accounts(
+            ancestors,
+            range,
+            |collector: &mut Vec<(Pubkey, Account)>, option| {
+                Self::load_while_filtering(collector, option, |_| true)
             },
         )
     }