From 19eb45376a22f5949e19b9f3f77f73b2f55d8ff7 Mon Sep 17 00:00:00 2001
From: MariusVanDerWijden <m.vanderwijden@live.de>
Date: Wed, 21 May 2025 16:39:58 +0200
Subject: [PATCH] core/vm: reuse stack arena

---
 core/state_prefetcher.go |  1 +
 core/state_processor.go  |  1 +
 core/vm/evm.go           |  6 ++++++
 core/vm/stack.go         | 17 ++++++++++++++---
 4 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/core/state_prefetcher.go b/core/state_prefetcher.go
index f3129f57cd..c94914845c 100644
--- a/core/state_prefetcher.go
+++ b/core/state_prefetcher.go
@@ -93,6 +93,7 @@ func (p *statePrefetcher) Prefetch(block *types.Block, statedb *state.StateDB, c
 			}
 			// Execute the message to preload the implicit touched states
 			evm := vm.NewEVM(NewEVMBlockContext(header, p.chain, nil), stateCpy, p.config, cfg)
+			defer evm.Free()
 
 			// Convert the transaction into an executable message and pre-cache its sender
 			msg, err := TransactionToMessage(tx, signer, header.BaseFee)
diff --git a/core/state_processor.go b/core/state_processor.go
index 322bd24f41..9e504e502b 100644
--- a/core/state_processor.go
+++ b/core/state_processor.go
@@ -81,6 +81,7 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 	}
 	context = NewEVMBlockContext(header, p.chain, nil)
 	evm := vm.NewEVM(context, tracingStateDB, p.config, cfg)
+	defer evm.Free()
 
 	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
 		ProcessBeaconBlockRoot(*beaconRoot, evm)
diff --git a/core/vm/evm.go b/core/vm/evm.go
index c3f11b31b9..46aafc908d 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -170,6 +170,12 @@ func (evm *EVM) Cancel() {
 	evm.abort.Store(true)
 }
 
+// Free returns some memory allocated by the EVM, should be called after the EVM was used
+// for the last time. Not necessary, but an improvement.
+func (evm *EVM) Free() {
+	returnStack(evm.arena)
+}
+
 // Cancelled returns true if Cancel has been called
 func (evm *EVM) Cancelled() bool {
 	return evm.abort.Load()
diff --git a/core/vm/stack.go b/core/vm/stack.go
index d2e93dcdf0..bf885744bb 100644
--- a/core/vm/stack.go
+++ b/core/vm/stack.go
@@ -18,6 +18,7 @@ package vm
 
 import (
 	"slices"
+	"sync"
 
 	"github.com/holiman/uint256"
 )
@@ -29,9 +30,19 @@ type stackArena struct {
 }
 
 func newArena() *stackArena {
-	return &stackArena{
-		data: make([]uint256.Int, 1025),
-	}
+	return stackPool.New().(*stackArena)
+}
+
+var stackPool = sync.Pool{
+	New: func() any {
+		return &stackArena{
+			data: make([]uint256.Int, 1025),
+		}
+	},
+}
+
+func returnStack(arena *stackArena) {
+	stackPool.Put(arena)
 }
 
 // stack returns an instance of a stack which uses the underlying arena. The instance