Add requeststate comments

peer.go

@@ -468,6 +468,8 @@ func (cn *Peer) request(r RequestIndex) (more bool, err error) {
 	return cn.peerImpl._request(ppReq), nil
 }
 
+var peerUpdateRequestsPeerCancelReason = "Peer.cancel"
+
 func (me *Peer) cancel(r RequestIndex) {
 	if !me.deleteRequest(r) {
 		panic("request not existing should have been guarded")
@@ -480,7 +482,7 @@ func (me *Peer) cancel(r RequestIndex) {
 	}
 	me.decPeakRequests()
 	if me.isLowOnRequests() {
-		me.updateRequests("Peer.cancel")
+		me.updateRequests(peerUpdateRequestsPeerCancelReason)
 	}
 }
 
@@ -566,6 +568,8 @@ func runSafeExtraneous(f func()) {
 	}
 }
 
+var peerUpdateRequestsRemoteRejectReason = "Peer.remoteRejectedRequest"
+
 // Returns true if it was valid to reject the request.
 func (c *Peer) remoteRejectedRequest(r RequestIndex) bool {
 	if c.deleteRequest(r) {
@@ -574,7 +578,7 @@ func (c *Peer) remoteRejectedRequest(r RequestIndex) bool {
 		return false
 	}
 	if c.isLowOnRequests() {
-		c.updateRequests("Peer.remoteRejectedRequest")
+		c.updateRequests(peerUpdateRequestsRemoteRejectReason)
 	}
 	c.decExpectedChunkReceive(r)
 	return true

requesting.go

@@ -312,12 +312,19 @@ func (p *Peer) applyRequestState(next desiredRequestState) {
 			panic("changed")
 		}
 
+		// don't add requests on receipt of a reject - because this causes request back
+		// to potentially permanently unresponsive peers - which just adds network noise.  If
+		// the peer can handle more requests it will send an "unchoked" message - which
+		// will cause it to get added back to the request queue
 		if p.needRequestUpdate == "Peer.remoteRejectedRequest" {
 			continue
 		}
 
 		existing := t.requestingPeer(req)
 		if existing != nil && existing != p {
+			// don't steal on cancel - because this is triggered by t.cancelRequest below
+			// which means that the cancelled can immediately try to steal back a request
+			// it has lost which can lead to circular cancel/add processing
 			if p.needRequestUpdate == "Peer.cancel" {
 				continue
 			}

webseed-peer.go

@@ -27,6 +27,7 @@ type webseedPeer struct {
 	client           webseed.Client
 	activeRequests   map[Request]webseed.Request
 	requesterCond    sync.Cond
+	updateRequestor  *time.Timer
 	lastUnhandledErr time.Time
 }
 
@@ -72,7 +73,6 @@ func (ws *webseedPeer) intoSpec(r Request) webseed.RequestSpec {
 }
 
 func (ws *webseedPeer) _request(r Request) bool {
-	ws.requesterCond.Signal()
 	return true
 }
 
@@ -91,15 +91,17 @@ func (ws *webseedPeer) doRequest(r Request) error {
 func (ws *webseedPeer) requester(i int) {
 	ws.requesterCond.L.Lock()
 	defer ws.requesterCond.L.Unlock()
-start:
+
 	for !ws.peer.closed.IsSet() {
 		// Restart is set if we don't need to wait for the requestCond before trying again.
 		restart := false
+
 		ws.peer.requestState.Requests.Iterate(func(x RequestIndex) bool {
 			r := ws.peer.t.requestIndexToRequest(x)
 			if _, ok := ws.activeRequests[r]; ok {
 				return true
 			}
+
 			err := ws.doRequest(r)
 			ws.requesterCond.L.Unlock()
 			if err != nil && !errors.Is(err, context.Canceled) {
@@ -117,10 +119,38 @@ start:
 			ws.requesterCond.L.Lock()
 			return false
 		})
-		if restart {
-			goto start
+
+		if !restart {
+			if !ws.peer.t.dataDownloadDisallowed.Bool() && ws.peer.isLowOnRequests() && len(ws.peer.getDesiredRequestState().Requests.requestIndexes) > 0 {
+				if ws.updateRequestor == nil {
+					ws.updateRequestor = time.AfterFunc(updateRequestsTimerDuration, func() { requestUpdate(ws) })
+				}
+			}
+
+			ws.requesterCond.Wait()
+
+			if ws.updateRequestor != nil {
+				ws.updateRequestor.Stop()
+				ws.updateRequestor = nil
+			}
+		}
+	}
+}
+
+func requestUpdate(ws *webseedPeer) {
+	if ws != nil {
+		if !ws.peer.closed.IsSet() {
+			if len(ws.peer.getDesiredRequestState().Requests.requestIndexes) > 0 {
+				if ws.peer.isLowOnRequests() {
+					if time.Since(ws.peer.lastRequestUpdate) > updateRequestsTimerDuration {
+						ws.peer.updateRequests(peerUpdateRequestsTimerReason)
+						return
+					}
+				}
+
+				ws.requesterCond.Signal()
+			}
 		}
-		ws.requesterCond.Wait()
 	}
 }
 
@@ -142,6 +172,7 @@ func (ws *webseedPeer) handleUpdateRequests() {
 		ws.peer.t.cl.lock()
 		defer ws.peer.t.cl.unlock()
 		ws.peer.maybeUpdateActualRequestState()
+		ws.requesterCond.Signal()
 	}()
 }