triedb/pathdb: remove sync pool

Author: rjl493456442

triedb/pathdb/lookup.go

@@ -25,26 +25,6 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-// slicePool is a shared pool of hash slice, for reducing the GC pressure.
-var slicePool = sync.Pool{
-	New: func() interface{} {
-		slice := make([]common.Hash, 0, 16) // Pre-allocate a slice with a reasonable capacity.
-		return &slice
-	},
-}
-
-// getSlice obtains the hash slice from the shared pool.
-func getSlice() []common.Hash {
-	slice := *slicePool.Get().(*[]common.Hash)
-	slice = slice[:0]
-	return slice
-}
-
-// returnSlice returns the hash slice back to the shared pool for following usage.
-func returnSlice(slice []common.Hash) {
-	slicePool.Put(&slice)
-}
-
 // lookup is an internal structure used to efficiently determine the layer in
 // which a state entry resides.
 type lookup struct {
@@ -159,7 +139,7 @@ func (l *lookup) addLayer(diff *diffLayer) {
 		for accountHash := range diff.states.accountData {
 			list, exists := l.accounts[accountHash]
 			if !exists {
-				list = getSlice()
+				list = make([]common.Hash, 0, 16)
 			}
 			list = append(list, state)
 			l.accounts[accountHash] = list
@@ -178,7 +158,7 @@ func (l *lookup) addLayer(diff *diffLayer) {
 			for slotHash := range slots {
 				list, exists := subset[slotHash]
 				if !exists {
-					list = getSlice()
+					list = make([]common.Hash, 0, 16)
 				}
 				list = append(list, state)
 				subset[slotHash] = list
@@ -212,7 +192,7 @@ func (l *lookup) removeLayer(diff *diffLayer) error {
 					if i == 0 {
 						list = list[1:]
 						if cap(list) > 1024 {
-							list = append(getSlice(), list...)
+							list = append(make([]common.Hash, 0, len(list)), list...)
 						}
 					} else {
 						list = append(list[:i], list[i+1:]...)
@@ -227,7 +207,6 @@ func (l *lookup) removeLayer(diff *diffLayer) error {
 			if len(list) != 0 {
 				l.accounts[accountHash] = list
 			} else {
-				returnSlice(list)
 				delete(l.accounts, accountHash)
 			}
 		}
@@ -252,7 +231,7 @@ func (l *lookup) removeLayer(diff *diffLayer) error {
 						if i == 0 {
 							list = list[1:]
 							if cap(list) > 1024 {
-								list = append(getSlice(), list...)
+								list = append(make([]common.Hash, 0, len(list)), list...)
 							}
 						} else {
 							list = append(list[:i], list[i+1:]...)
@@ -267,7 +246,6 @@ func (l *lookup) removeLayer(diff *diffLayer) error {
 				if len(list) != 0 {
 					subset[slotHash] = list
 				} else {
-					returnSlice(subset[slotHash])
 					delete(subset, slotHash)
 				}
 			}