From deab944b3000db4c7f33c775d7fbf9cd003079b4 Mon Sep 17 00:00:00 2001
From: "Jeff Washington (jwash)"
 <75863576+jeffwashington@users.noreply.github.com>
Date: Wed, 22 Sep 2021 09:55:40 -0500
Subject: [PATCH] AcctIdx: flush inserts to disk (#20074)

---
 runtime/src/bucket_map_holder_stats.rs | 25 +++++++++++
 runtime/src/in_mem_accounts_index.rs   | 60 ++++++++++++++++++++------
 2 files changed, 73 insertions(+), 12 deletions(-)

diff --git a/runtime/src/bucket_map_holder_stats.rs b/runtime/src/bucket_map_holder_stats.rs
index c77179573c..6073b03ecc 100644
--- a/runtime/src/bucket_map_holder_stats.rs
+++ b/runtime/src/bucket_map_holder_stats.rs
@@ -22,10 +22,14 @@ pub struct BucketMapHolderStats {
     pub inserts: AtomicU64,
     pub count_in_mem: AtomicU64,
     pub per_bucket_count: Vec<AtomicU64>,
+    pub flush_entries_updated_on_disk: AtomicU64,
     pub active_threads: AtomicU64,
     pub get_range_us: AtomicU64,
     last_age: AtomicU8,
     last_age_time: AtomicU64,
+    pub flush_scan_us: AtomicU64,
+    pub flush_update_us: AtomicU64,
+    pub flush_remove_us: AtomicU64,
     last_time: AtomicInterval,
 }
 
@@ -163,6 +167,27 @@ impl BucketMapHolderStats {
             ("items", self.items.swap(0, Ordering::Relaxed), i64),
             ("keys", self.keys.swap(0, Ordering::Relaxed), i64),
             ("ms_per_age", ms_per_age, i64),
+            (
+                "flush_scan_us",
+                self.flush_scan_us.swap(0, Ordering::Relaxed),
+                i64
+            ),
+            (
+                "flush_update_us",
+                self.flush_update_us.swap(0, Ordering::Relaxed),
+                i64
+            ),
+            (
+                "flush_remove_us",
+                self.flush_remove_us.swap(0, Ordering::Relaxed),
+                i64
+            ),
+            (
+                "flush_entries_updated_on_disk",
+                self.flush_entries_updated_on_disk
+                    .swap(0, Ordering::Relaxed),
+                i64
+            ),
         );
     }
 }
diff --git a/runtime/src/in_mem_accounts_index.rs b/runtime/src/in_mem_accounts_index.rs
index bf7fb414d0..cf56f2020f 100644
--- a/runtime/src/in_mem_accounts_index.rs
+++ b/runtime/src/in_mem_accounts_index.rs
@@ -515,6 +515,11 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
         self.storage.wait_dirty_or_aged.notify_one();
     }
 
+    fn should_remove_from_mem(&self, current_age: Age, entry: &AccountMapEntry<T>) -> bool {
+        // this could be tunable dynamically based on memory pressure
+        current_age == entry.age()
+    }
+
     fn flush_internal(&self) {
         let was_dirty = self.bin_dirty.swap(false, Ordering::Acquire);
         let current_age = self.storage.current_age();
@@ -524,21 +529,52 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
             return;
         }
 
-        let map = self.map().read().unwrap();
-        for (_k, _v) in map.iter() {
-            /*
-            if v.dirty() {
-                // step 1: clear the dirty flag
-                // step 2: perform the update on disk based on the fields in the entry
-                // If a parallel operation dirties the item again - even while this flush is occurring,
-                //  the last thing the writer will do, after updating contents, is set_dirty(true)
-                //  That prevents dropping an item from cache before disk is updated to latest in mem.
-                v.set_dirty(false);
+        let mut removes = Vec::default();
+        let disk = self.storage.disk.as_ref().unwrap();
 
-                // soon, this will update disk from the in-mem contents
+        let mut updates = Vec::default();
+        let m = Measure::start("flush_scan");
+        // scan and update loop
+        {
+            let map = self.map().read().unwrap();
+            for (k, v) in map.iter() {
+                if v.dirty() {
+                    // step 1: clear the dirty flag
+                    // step 2: perform the update on disk based on the fields in the entry
+                    // If a parallel operation dirties the item again - even while this flush is occurring,
+                    //  the last thing the writer will do, after updating contents, is set_dirty(true)
+                    //  That prevents dropping an item from cache before disk is updated to latest in mem.
+                    v.set_dirty(false);
+
+                    updates.push((*k, Arc::clone(v)));
+                }
+
+                if self.should_remove_from_mem(current_age, v) {
+                    removes.push(*k);
+                }
             }
-            */
         }
+        Self::update_time_stat(&self.stats().flush_scan_us, m);
+
+        let mut flush_entries_updated_on_disk = 0;
+        // happens outside of lock on in-mem cache
+        // it is possible that the item in the cache is marked as dirty while these updates are happening. That is ok.
+        let m = Measure::start("flush_update");
+        for (k, v) in updates.into_iter() {
+            if v.dirty() {
+                continue; // marked dirty after we grabbed it above, so handle this the next time this bucket is flushed
+            }
+            flush_entries_updated_on_disk += 1;
+            disk.insert(&k, (&v.slot_list.read().unwrap(), v.ref_count()));
+        }
+        Self::update_time_stat(&self.stats().flush_update_us, m);
+        Self::update_stat(
+            &self.stats().flush_entries_updated_on_disk,
+            flush_entries_updated_on_disk,
+        );
+
+        // loop that processes 'removes' will go here
+
         if iterate_for_age {
             // completed iteration of the buckets at the current age
             assert_eq!(current_age, self.storage.current_age());