net: add a flag to indicate when a node's process queue is full

Messages are dumped very quickly from the socket handler to the processor, so
it's the depth of the processing queue that's interesting.

The socket handler checks the process queue's size during the brief message
hand-off and pauses if necessary, and the processor possibly unpauses each time
a message is popped off of its queue.

1 files changed, 7 insertions, 3 deletions

diff --git a/src/net.cpp b/src/net.cpp
index df2109e3f..70c04d7a0 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1165,9 +1165,7 @@ void CConnman::ThreadSocketHandler()
                 }
                 {
                     TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
-                    if (lockRecv && (
-                        pnode->vRecvMsg.empty() || !pnode->vRecvMsg.front().complete() ||
-                        pnode->GetTotalRecvSize() <= GetReceiveFloodSize()))
+                    if (lockRecv && !pnode->fPauseRecv)
                         FD_SET(pnode->hSocket, &fdsetRecv);
                 }
             }
@@ -1240,14 +1238,18 @@ void CConnman::ThreadSocketHandler()
                                 pnode->CloseSocketDisconnect();
                             RecordBytesRecv(nBytes);
                             if (notify) {
+                                size_t nSizeAdded = 0;
                                 auto it(pnode->vRecvMsg.begin());
                                 for (; it != pnode->vRecvMsg.end(); ++it) {
                                     if (!it->complete())
                                         break;
+                                    nSizeAdded += it->vRecv.size() + CMessageHeader::HEADER_SIZE;
                                 }
                                 {
                                     LOCK(pnode->cs_vProcessMsg);
                                     pnode->vProcessMsg.splice(pnode->vProcessMsg.end(), pnode->vRecvMsg, pnode->vRecvMsg.begin(), it);
+                                    pnode->nProcessQueueSize += nSizeAdded;
+                                    pnode->fPauseRecv = pnode->nProcessQueueSize > nReceiveFloodSize;
                                 }
                                 WakeMessageHandler();
                             }
@@ -2592,6 +2594,8 @@ CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn
     minFeeFilter = 0;
     lastSentFeeFilter = 0;
     nextSendTimeFeeFilter = 0;
+    fPauseRecv = false;
+    nProcessQueueSize = 0;
 
     BOOST_FOREACH(const std::string &msg, getAllNetMessageTypes())
         mapRecvBytesPerMsgCmd[msg] = 0;