move hash calculation out of acct bg svc (#23689)

* move hash calculation out of acct bg svc

* pr feedback

runtime/src/accounts_background_service.rs

@@ -4,6 +4,7 @@
 
 use {
     crate::{
+        accounts_hash::CalcAccountsHashConfig,
         bank::{Bank, BankSlotDelta, DropCallback},
         bank_forks::BankForks,
         snapshot_config::SnapshotConfig,
@@ -109,7 +110,7 @@ impl SnapshotRequestHandler {
 
                 let previous_hash = if test_hash_calculation {
                     // We have to use the index version here.
-                    // We cannot calculate the non-index way because cache has not been flushed and stores don't match reality.
+                    // We cannot calculate the non-index way because cache has not been flushed and stores don't match reality. This comment is out of date and can be re-evaluated.
                     snapshot_root_bank.update_accounts_hash_with_index_option(true, false, false)
                 } else {
                     Hash::default()
@@ -144,20 +145,27 @@ impl SnapshotRequestHandler {
                 }
                 flush_accounts_cache_time.stop();
 
-                let use_index_hash_calculation = false;
-                let mut hash_time = Measure::start("hash_time");
-                let this_hash = snapshot_root_bank.update_accounts_hash_with_index_option(
-                    use_index_hash_calculation,
-                    test_hash_calculation,
-                    false,
-                );
                 let hash_for_testing = if test_hash_calculation {
+                    let use_index_hash_calculation = false;
+                    let check_hash = false;
+
+                    let (this_hash, _cap) = snapshot_root_bank.accounts().accounts_db.calculate_accounts_hash_helper(
+                        use_index_hash_calculation,
+                        snapshot_root_bank.slot(),
+                        &CalcAccountsHashConfig {
+                            use_bg_thread_pool: true,
+                            check_hash,
+                            ancestors: None,
+                            use_write_cache: false,
+                            epoch_schedule: snapshot_root_bank.epoch_schedule(),
+                            rent_collector: &snapshot_root_bank.rent_collector(),
+                        },
+                    ).unwrap();
                     assert_eq!(previous_hash, this_hash);
-                    Some(snapshot_root_bank.get_accounts_hash())
+                    Some(this_hash)
                 } else {
                     None
                 };
-                hash_time.stop();
 
                 let mut clean_time = Measure::start("clean_time");
                 // Don't clean the slot we're snapshotting because it may have zero-lamport
@@ -234,7 +242,6 @@ impl SnapshotRequestHandler {
 
                 datapoint_info!(
                     "handle_snapshot_requests-timing",
-                    ("hash_time", hash_time.as_us(), i64),
                     (
                         "flush_accounts_cache_time",
                         flush_accounts_cache_time.as_us(),

runtime/src/accounts_db.rs

@@ -5505,7 +5505,7 @@ impl AccountsDb {
         }
     }
 
-    fn calculate_accounts_hash_helper(
+    pub(crate) fn calculate_accounts_hash_helper(
         &self,
         use_index: bool,
         slot: Slot,

runtime/src/snapshot_package.rs

@@ -37,7 +37,6 @@ pub struct AccountsPackage {
     pub slot_deltas: Vec<BankSlotDelta>,
     pub snapshot_links: TempDir,
     pub snapshot_storages: SnapshotStorages,
-    pub accounts_hash: Hash, // temporarily here while we still have to calculate hash before serializing bank
     pub archive_format: ArchiveFormat,
     pub snapshot_version: SnapshotVersion,
     pub snapshot_archives_dir: PathBuf,
@@ -104,7 +103,6 @@ impl AccountsPackage {
             slot_deltas,
             snapshot_links,
             snapshot_storages,
-            accounts_hash: bank.get_accounts_hash(),
             archive_format,
             snapshot_version,
             snapshot_archives_dir: snapshot_archives_dir.as_ref().to_path_buf(),
@@ -129,8 +127,8 @@ pub struct SnapshotPackage {
     pub snapshot_type: SnapshotType,
 }
 
-impl From<AccountsPackage> for SnapshotPackage {
-    fn from(accounts_package: AccountsPackage) -> Self {
+impl SnapshotPackage {
+    pub fn new(accounts_package: AccountsPackage, accounts_hash: Hash) -> Self {
         assert!(
             accounts_package.snapshot_type.is_some(),
             "Cannot make a SnapshotPackage from an AccountsPackage when SnapshotType is None!"
@@ -141,7 +139,7 @@ impl From<AccountsPackage> for SnapshotPackage {
             SnapshotType::FullSnapshot => snapshot_utils::build_full_snapshot_archive_path(
                 accounts_package.snapshot_archives_dir,
                 accounts_package.slot,
-                &accounts_package.accounts_hash,
+                &accounts_hash,
                 accounts_package.archive_format,
             ),
             SnapshotType::IncrementalSnapshot(incremental_snapshot_base_slot) => {
@@ -161,7 +159,7 @@ impl From<AccountsPackage> for SnapshotPackage {
                     accounts_package.snapshot_archives_dir,
                     incremental_snapshot_base_slot,
                     accounts_package.slot,
-                    &accounts_package.accounts_hash,
+                    &accounts_hash,
                     accounts_package.archive_format,
                 )
             }
@@ -171,7 +169,7 @@ impl From<AccountsPackage> for SnapshotPackage {
             snapshot_archive_info: SnapshotArchiveInfo {
                 path: snapshot_archive_path,
                 slot: accounts_package.slot,
-                hash: accounts_package.accounts_hash,
+                hash: accounts_hash,
                 archive_format: accounts_package.archive_format,
             },
             block_height: accounts_package.block_height,

runtime/src/snapshot_utils.rs

@@ -1924,7 +1924,7 @@ pub fn package_and_archive_full_snapshot(
         &bank.get_accounts_hash(),
     );
 
-    let snapshot_package = SnapshotPackage::from(accounts_package);
+    let snapshot_package = SnapshotPackage::new(accounts_package, bank.get_accounts_hash());
     archive_snapshot_package(
         &snapshot_package,
         maximum_full_snapshot_archives_to_retain,
@@ -1971,7 +1971,7 @@ pub fn package_and_archive_incremental_snapshot(
         &bank.get_accounts_hash(),
     );
 
-    let snapshot_package = SnapshotPackage::from(accounts_package);
+    let snapshot_package = SnapshotPackage::new(accounts_package, bank.get_accounts_hash());
     archive_snapshot_package(
         &snapshot_package,
         maximum_full_snapshot_archives_to_retain,
@@ -3443,7 +3443,6 @@ mod tests {
                 slot_deltas: Vec::default(),
                 snapshot_links: TempDir::new().unwrap(),
                 snapshot_storages: SnapshotStorages::default(),
-                accounts_hash: Hash::default(),
                 archive_format: ArchiveFormat::Tar,
                 snapshot_version: SnapshotVersion::default(),
                 snapshot_archives_dir: PathBuf::default(),