From ebabc53cee67bbba6c420ecd8756a2d3848c8f75 Mon Sep 17 00:00:00 2001
From: "Jeff Washington (jwash)" <wash678@gmail.com>
Date: Sun, 31 Jul 2022 21:04:15 -0500
Subject: [PATCH] use Vec::drain instead of option/take (#26852)

---
 runtime/src/in_mem_accounts_index.rs | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/runtime/src/in_mem_accounts_index.rs b/runtime/src/in_mem_accounts_index.rs
index 4d9042cfe7..89babf1dad 100644
--- a/runtime/src/in_mem_accounts_index.rs
+++ b/runtime/src/in_mem_accounts_index.rs
@@ -77,9 +77,9 @@ struct StartupInfo<T: IndexValue> {
 /// result from scanning in-mem index during flush
 struct FlushScanResult<T> {
     /// pubkeys whose age indicates they may be evicted now, pending further checks.
-    evictions_age_possible: Vec<(Pubkey, Option<AccountMapEntry<T>>)>,
+    evictions_age_possible: Vec<(Pubkey, AccountMapEntry<T>)>,
     /// pubkeys chosen to evict based on random eviction
-    evictions_random: Vec<(Pubkey, Option<AccountMapEntry<T>>)>,
+    evictions_random: Vec<(Pubkey, AccountMapEntry<T>)>,
 }
 
 impl<T: IndexValue> InMemAccountsIndex<T> {
@@ -992,7 +992,7 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
                 } else {
                     &mut evictions_age_possible
                 }
-                .push((*k, Some(Arc::clone(v))));
+                .push((*k, Arc::clone(v)));
             }
         }
         Self::update_time_stat(&self.stats().flush_scan_us, m);
@@ -1104,8 +1104,7 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
                     (false, &mut evictions_age_possible),
                     (true, &mut evictions_random),
                 ] {
-                    for (k, v) in check_for_eviction_and_dirty {
-                        let v = v.take().unwrap();
+                    for (k, v) in check_for_eviction_and_dirty.drain(..) {
                         let mut slot_list = None;
                         if !is_random {
                             let mut mse = Measure::start("flush_should_evict");
@@ -1120,7 +1119,7 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
                             mse.stop();
                             flush_should_evict_us += mse.as_us();
                             if evict_for_age {
-                                evictions_age.push(*k);
+                                evictions_age.push(k);
                             } else {
                                 // not evicting, so don't write, even if dirty
                                 continue;
@@ -1142,7 +1141,7 @@ impl<T: IndexValue> InMemAccountsIndex<T> {
                                     let slot_list = slot_list
                                         .take()
                                         .unwrap_or_else(|| v.slot_list.read().unwrap());
-                                    disk.try_write(k, (&slot_list, v.ref_count()))
+                                    disk.try_write(&k, (&slot_list, v.ref_count()))
                                 };
                                 match disk_resize {
                                     Ok(_) => {