Adds AtomicAge to bucket map holder (solana-labs#33841)

accounts-db/src/accounts_index.rs

@@ -3,7 +3,7 @@ use {
         accounts_index_storage::{AccountsIndexStorage, Startup},
         accounts_partition::RentPayingAccountsByPartition,
         ancestors::Ancestors,
-        bucket_map_holder::{Age, BucketMapHolder},
+        bucket_map_holder::{Age, AtomicAge, BucketMapHolder},
         contains::Contains,
         in_mem_accounts_index::{InMemAccountsIndex, InsertNewEntryResults, StartupStats},
         inline_spl_token::{self, GenericTokenAccount},
@@ -36,7 +36,7 @@ use {
         },
         path::PathBuf,
         sync::{
-            atomic::{AtomicBool, AtomicU64, AtomicU8, AtomicUsize, Ordering},
+            atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering},
             Arc, Mutex, OnceLock, RwLock, RwLockReadGuard, RwLockWriteGuard,
         },
     },
@@ -238,7 +238,7 @@ pub struct AccountMapEntryMeta {
     /// true if entry in in-mem idx has changes and needs to be written to disk
     pub dirty: AtomicBool,
     /// 'age' at which this entry should be purged from the cache (implements lru)
-    pub age: AtomicU8,
+    pub age: AtomicAge,
 }
 
 impl AccountMapEntryMeta {
@@ -248,15 +248,15 @@ impl AccountMapEntryMeta {
     ) -> Self {
         AccountMapEntryMeta {
             dirty: AtomicBool::new(true),
-            age: AtomicU8::new(storage.future_age_to_flush(is_cached)),
+            age: AtomicAge::new(storage.future_age_to_flush(is_cached)),
         }
     }
     pub fn new_clean<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>>(
         storage: &Arc<BucketMapHolder<T, U>>,
     ) -> Self {
         AccountMapEntryMeta {
             dirty: AtomicBool::new(false),
-            age: AtomicU8::new(storage.future_age_to_flush(false)),
+            age: AtomicAge::new(storage.future_age_to_flush(false)),
         }
     }
 }
@@ -2113,7 +2113,7 @@ pub mod tests {
                     let (slot, account_info) = entry.slot_list.read().unwrap()[0];
                     let meta = AccountMapEntryMeta {
                         dirty: AtomicBool::new(entry.dirty()),
-                        age: AtomicU8::new(entry.age()),
+                        age: AtomicAge::new(entry.age()),
                     };
                     PreAllocatedAccountMapEntry::Entry(Arc::new(AccountMapEntryInner::new(
                         vec![(slot, account_info)],

accounts-db/src/bucket_map_holder.rs

@@ -22,6 +22,8 @@ use {
     },
 };
 pub type Age = u8;
+pub type AtomicAge = AtomicU8;
+const _: () = assert!(std::mem::size_of::<Age>() == std::mem::size_of::<AtomicAge>());
 
 const AGE_MS: u64 = DEFAULT_MS_PER_SLOT; // match one age per slot time
 
@@ -37,12 +39,12 @@ pub struct BucketMapHolder<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>>
     /// Instead of accessing the single age and doing math each time, each value is incremented each time the age occurs, which is ~400ms.
     /// Callers can ask for the precomputed value they already want.
     /// rolling 'current' age
-    pub age: AtomicU8,
+    pub age: AtomicAge,
     /// rolling age that is 'ages_to_stay_in_cache' + 'age'
-    pub future_age_to_flush: AtomicU8,
+    pub future_age_to_flush: AtomicAge,
     /// rolling age that is effectively 'age' - 1
     /// these items are expected to be flushed from the accounts write cache or otherwise modified before this age occurs
-    pub future_age_to_flush_cached: AtomicU8,
+    pub future_age_to_flush_cached: AtomicAge,
 
     pub stats: BucketMapHolderStats,
 
@@ -255,11 +257,11 @@ impl<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> BucketMapHolder<T, U>
             ages_to_stay_in_cache,
             count_buckets_flushed: AtomicUsize::default(),
             // age = 0
-            age: AtomicU8::default(),
+            age: AtomicAge::default(),
             // future age = age (=0) + ages_to_stay_in_cache
-            future_age_to_flush: AtomicU8::new(ages_to_stay_in_cache),
+            future_age_to_flush: AtomicAge::new(ages_to_stay_in_cache),
             // effectively age (0) - 1. So, the oldest possible age from 'now'
-            future_age_to_flush_cached: AtomicU8::new(0_u8.wrapping_sub(1)),
+            future_age_to_flush_cached: AtomicAge::new(Age::MAX),
             stats: BucketMapHolderStats::new(bins),
             wait_dirty_or_aged: Arc::default(),
             next_bucket_to_flush: AtomicUsize::new(0),
@@ -442,7 +444,7 @@ pub mod tests {
         let test = BucketMapHolder::<u64, u64>::new(bins, &Some(AccountsIndexConfig::default()), 1);
         assert_eq!(0, test.current_age());
         assert_eq!(test.ages_to_stay_in_cache, test.future_age_to_flush(false));
-        assert_eq!(u8::MAX, test.future_age_to_flush(true));
+        assert_eq!(Age::MAX, test.future_age_to_flush(true));
         (0..bins).for_each(|_| {
             test.bucket_flushed_at_current_age(false);
         });

accounts-db/src/bucket_map_holder_stats.rs

@@ -1,12 +1,12 @@
 use {
     crate::{
         accounts_index::{DiskIndexValue, IndexValue},
-        bucket_map_holder::BucketMapHolder,
+        bucket_map_holder::{Age, AtomicAge, BucketMapHolder},
     },
     solana_sdk::timing::AtomicInterval,
     std::{
         fmt::Debug,
-        sync::atomic::{AtomicBool, AtomicU64, AtomicU8, AtomicUsize, Ordering},
+        sync::atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering},
     },
 };
 
@@ -52,7 +52,7 @@ pub struct BucketMapHolderStats {
     pub flush_entries_evicted_from_mem: AtomicU64,
     pub active_threads: AtomicU64,
     pub get_range_us: AtomicU64,
-    last_age: AtomicU8,
+    last_age: AtomicAge,
     last_ages_flushed: AtomicU64,
     pub flush_scan_us: AtomicU64,
     pub flush_update_us: AtomicU64,
@@ -120,7 +120,7 @@ impl BucketMapHolderStats {
         let mut age_now = age_now as u64;
         if last_age > age_now {
             // age wrapped
-            age_now += u8::MAX as u64 + 1;
+            age_now += Age::MAX as u64 + 1;
         }
         let age_delta = age_now.saturating_sub(last_age);
         if age_delta > 0 {

accounts-db/src/in_mem_accounts_index.rs

@@ -4,7 +4,7 @@ use {
             AccountMapEntry, AccountMapEntryInner, AccountMapEntryMeta, DiskIndexValue, IndexValue,
             PreAllocatedAccountMapEntry, RefCount, SlotList, UpsertReclaim, ZeroLamport,
         },
-        bucket_map_holder::{Age, BucketMapHolder},
+        bucket_map_holder::{Age, AtomicAge, BucketMapHolder},
         bucket_map_holder_stats::BucketMapHolderStats,
         waitable_condvar::WaitableCondvar,
     },
@@ -17,7 +17,7 @@ use {
         fmt::Debug,
         ops::{Bound, RangeBounds, RangeInclusive},
         sync::{
-            atomic::{AtomicBool, AtomicU64, AtomicU8, Ordering},
+            atomic::{AtomicBool, AtomicU64, Ordering},
             Arc, Mutex, RwLock, RwLockWriteGuard,
         },
     },
@@ -89,7 +89,7 @@ impl<T: IndexValue> PossibleEvictions<T> {
 
 // one instance of this represents one bin of the accounts index.
 pub struct InMemAccountsIndex<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> {
-    last_age_flushed: AtomicU8,
+    last_age_flushed: AtomicAge,
 
     // backing store
     map_internal: RwLock<InMemMap<T>>,
@@ -115,7 +115,7 @@ pub struct InMemAccountsIndex<T: IndexValue, U: DiskIndexValue + From<T> + Into<
 
     /// how many more ages to skip before this bucket is flushed (as opposed to being skipped).
     /// When this reaches 0, this bucket is flushed.
-    remaining_ages_to_skip_flushing: AtomicU8,
+    remaining_ages_to_skip_flushing: AtomicAge,
 
     /// an individual bucket will evict its entries and write to disk every 1/NUM_AGES_TO_DISTRIBUTE_FLUSHES ages
     /// Higher numbers mean we flush less buckets/s
@@ -181,12 +181,12 @@ impl<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> InMemAccountsIndex<T,
             stop_evictions: AtomicU64::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),
+            last_age_flushed: AtomicAge::new(Age::MAX),
             startup_info: StartupInfo::default(),
             possible_evictions: RwLock::new(PossibleEvictions::new(1)),
             // Spread out the scanning across all ages within the window.
             // This causes us to scan 1/N of the bins each 'Age'
-            remaining_ages_to_skip_flushing: AtomicU8::new(
+            remaining_ages_to_skip_flushing: AtomicAge::new(
                 thread_rng().gen_range(0..num_ages_to_distribute_flushes),
             ),
             num_ages_to_distribute_flushes,