incorporate suggestions

mempool/cat/cache.go

@@ -15,9 +15,11 @@ import (
 type LRUTxCache struct {
 	staticSize int
 
-	mtx      tmsync.Mutex
+	mtx tmsync.Mutex
+	// cacheMap is used as a quick look up table
 	cacheMap map[types.TxKey]*list.Element
-	list     *list.List
+	// list is a doubly linked list used to capture the FIFO nature of the cache
+	list *list.List
 }
 
 func NewLRUTxCache(cacheSize int) *LRUTxCache {
@@ -66,6 +68,10 @@ func (c *LRUTxCache) Push(txKey types.TxKey) bool {
 }
 
 func (c *LRUTxCache) Remove(txKey types.TxKey) {
+	if c.staticSize == 0 {
+		return
+	}
+
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
@@ -107,7 +113,7 @@ type EvictedTxCache struct {
 func NewEvictedTxCache(size int) *EvictedTxCache {
 	return &EvictedTxCache{
 		staticSize: size,
-		cache:      make(map[types.TxKey]*EvictedTxInfo),
+		cache:      make(map[types.TxKey]*EvictedTxInfo, size+1),
 	}
 }
 
@@ -183,7 +189,7 @@ type SeenTxSet struct {
 }
 
 type timestampedPeerSet struct {
-	peers map[uint16]bool
+	peers map[uint16]struct{}
 	time  time.Time
 }
 
@@ -202,11 +208,11 @@ func (s *SeenTxSet) Add(txKey types.TxKey, peer uint16) {
 	seenSet, exists := s.set[txKey]
 	if !exists {
 		s.set[txKey] = timestampedPeerSet{
-			peers: map[uint16]bool{peer: true},
+			peers: map[uint16]struct{}{peer: struct{}{}},
 			time:  time.Now().UTC(),
 		}
 	} else {
-		seenSet.peers[peer] = true
+		seenSet.peers[peer] = struct{}{}
 	}
 }
 
@@ -259,7 +265,8 @@ func (s *SeenTxSet) Has(txKey types.TxKey, peer uint16) bool {
 	if !exists {
 		return false
 	}
-	return seenSet.peers[peer]
+	_, has := seenSet.peers[peer]
+	return has
 }
 
 func (s *SeenTxSet) Get(txKey types.TxKey) map[uint16]struct{} {

mempool/cat/cache_test.go

@@ -127,7 +127,7 @@ func TestSeenTxSetConcurrency(t *testing.T) {
 				tx := types.Tx([]byte(fmt.Sprintf("tx%d", i)))
 				seenSet.Add(tx.Key(), peer)
 			}
-		}(uint16(i%2))
+		}(uint16(i % 2))
 	}
 	time.Sleep(time.Millisecond)
 	for i := 0; i < concurrency; i++ {
@@ -138,18 +138,18 @@ func TestSeenTxSetConcurrency(t *testing.T) {
 				tx := types.Tx([]byte(fmt.Sprintf("tx%d", i)))
 				seenSet.Has(tx.Key(), peer)
 			}
-		}(uint16(i%2))
+		}(uint16(i % 2))
 	}
 	time.Sleep(time.Millisecond)
 	for i := 0; i < concurrency; i++ {
 		wg.Add(1)
 		go func(peer uint16) {
 			defer wg.Done()
-			for i := numTx-1; i >= 0; i-- {
+			for i := numTx - 1; i >= 0; i-- {
 				tx := types.Tx([]byte(fmt.Sprintf("tx%d", i)))
 				seenSet.RemoveKey(tx.Key())
 			}
-		}(uint16(i%2))
+		}(uint16(i % 2))
 	}
 	wg.Wait()
 }
@@ -175,7 +175,7 @@ func TestLRUTxCacheConcurrency(t *testing.T) {
 				tx := types.Tx([]byte(fmt.Sprintf("tx%d", i)))
 				cache.Has(tx.Key())
 			}
-			for i := numTx-1; i >= 0; i-- {
+			for i := numTx - 1; i >= 0; i-- {
 				tx := types.Tx([]byte(fmt.Sprintf("tx%d", i)))
 				cache.Remove(tx.Key())
 			}

mempool/cat/peers.go

@@ -8,13 +8,13 @@ import (
 	"github.com/tendermint/tendermint/p2p"
 )
 
-const firstPeerID = 1
+const firstPeerID = mempool.UnknownPeerID + 1
 
-// mempoolIDs is a thread-safe map of peer IDs to short IDs used for tracking what peers have sent what
-// NOTE: taken from mempool/v1/reactor.go
+// mempoolIDs is a thread-safe map of peer IDs to shorter uint16 IDs used by the Reactor for tracking peer
+// messages and peer state such as what transactions peers have seen
 type mempoolIDs struct {
 	mtx       tmsync.RWMutex
-	peerMap   map[p2p.ID]uint16
+	peerMap   map[p2p.ID]uint16   // quick lookup table for peer ID to short ID
 	nextID    uint16              // assumes that a node will never have over 65536 active peers
 	activeIDs map[uint16]p2p.Peer // used to check if a given peerID key is used, the value doesn't matter
 }