AcctIdx: introduce age per in-mem bucket (#19982)

runtime/src/in_mem_accounts_index.rs

@@ -1,13 +1,13 @@
 use crate::accounts_index::{
     AccountMapEntry, AccountMapEntryInner, IndexValue, SlotList, WriteAccountMapEntry,
 };
-use crate::bucket_map_holder::BucketMapHolder;
+use crate::bucket_map_holder::{Age, BucketMapHolder};
 use crate::bucket_map_holder_stats::BucketMapHolderStats;
 use solana_measure::measure::Measure;
 use solana_sdk::{clock::Slot, pubkey::Pubkey};
 use std::collections::{hash_map::Entry, HashMap};
 use std::ops::{Bound, RangeBounds, RangeInclusive};
-use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU64, AtomicU8, Ordering};
 use std::sync::{Arc, RwLock};
 
 use std::fmt::Debug;
@@ -15,8 +15,11 @@ type K = Pubkey;
 type CacheRangesHeld = RwLock<Vec<Option<RangeInclusive<Pubkey>>>>;
 pub type SlotT<T> = (Slot, T);
 
-// one instance of this represents one bin of the accounts index.
+#[allow(dead_code)] // temporary during staging
+                    // one instance of this represents one bin of the accounts index.
 pub struct InMemAccountsIndex<T: IndexValue> {
+    last_age_flushed: AtomicU8,
+
     // backing store
     map_internal: RwLock<HashMap<Pubkey, AccountMapEntry<T>>>,
     storage: Arc<BucketMapHolder<T>>,
@@ -38,6 +41,7 @@ impl<T: IndexValue> Debug for InMemAccountsIndex<T> {
     }
 }
 
+#[allow(dead_code)] // temporary during staging
 impl<T: IndexValue> InMemAccountsIndex<T> {
     pub fn new(storage: &Arc<BucketMapHolder<T>>, bin: usize) -> Self {
         Self {
@@ -48,9 +52,24 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
             stop_flush: AtomicU64::default(),
             bin_dirty: AtomicBool::default(),
             flushing_active: AtomicBool::default(),
+            // initialize this to max, to make it clear we have not flushed at age 0, the starting age
+            last_age_flushed: AtomicU8::new(Age::MAX),
         }
     }
 
+    /// true if this bucket needs to call flush for the current age
+    /// we need to scan each bucket once per value of age
+    fn get_should_age(&self) -> bool {
+        let last_age_flushed = self.last_age_flushed.load(Ordering::Relaxed);
+        let age = self.storage.age.load(Ordering::Relaxed);
+        last_age_flushed == age
+    }
+
+    /// called after flush scans this bucket at the current age
+    fn set_has_aged(&self, age: Age) {
+        self.last_age_flushed.store(age, Ordering::Relaxed);
+    }
+
     fn map(&self) -> &RwLock<HashMap<Pubkey, AccountMapEntry<T>>> {
         &self.map_internal
     }
@@ -484,4 +503,13 @@ mod tests {
             assert!(accts.cache_ranges_held.read().unwrap().is_empty());
         }
     }
+
+    #[test]
+    fn test_age() {
+        solana_logger::setup();
+        let test = new_for_test::<u64>();
+        assert!(!test.get_should_age());
+        test.set_has_aged(0);
+        assert!(test.get_should_age());
+    }
 }