Discard acks from QUIC's UnackedPacketMap when the map is larger than

net/quic/quic_unacked_packet_map.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_unacked_packet_map.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "net/quic/quic_connection_stats.h"
 #include "net/quic/quic_utils_chromium.h"
 
 using std::max;
 
 namespace net {
 
-namespace {
-
-// Maximum amount of reordering before packets are considered useless for
-// RTT measurement purposes.
-const QuicPacketCount kMaxReorderingForRtt = 200;
-
-}  // anonymous namespace
-
 QuicUnackedPacketMap::QuicUnackedPacketMap()
     : largest_sent_packet_(0),
       largest_observed_(0),
       least_unacked_(1),
       bytes_in_flight_(0),
       pending_crypto_packet_count_(0) {
 }
 
 QuicUnackedPacketMap::~QuicUnackedPacketMap() {
   QuicPacketSequenceNumber index = least_unacked_;
@@ skipping 240 matching lines @@
     const TransmissionInfo& info) const {
   return !IsPacketUsefulForMeasuringRtt(sequence_number, info) &&
          !IsPacketUsefulForCongestionControl(info) &&
          !IsPacketUsefulForRetransmittableData(info);
 }
 
 bool QuicUnackedPacketMap::IsPacketRemovable(
     QuicPacketSequenceNumber sequence_number,
     const TransmissionInfo& info) const {
   return (!IsPacketUsefulForMeasuringRtt(sequence_number, info) ||
-          unacked_packets_.size() > kMaxReorderingForRtt) &&
+          unacked_packets_.size() > kMaxTrackedPackets / 2) &&
          !IsPacketUsefulForCongestionControl(info) &&
          !IsPacketUsefulForRetransmittableData(info);
 }
 
 bool QuicUnackedPacketMap::IsUnacked(
     QuicPacketSequenceNumber sequence_number) const {
   if (sequence_number < least_unacked_ ||
       sequence_number >= least_unacked_ + unacked_packets_.size()) {
     return false;
   }
@@ skipping 90 matching lines @@
     }
   }
   return false;
 }
 
 QuicPacketSequenceNumber QuicUnackedPacketMap::GetLeastUnacked() const {
   return least_unacked_;
 }
 
 }  // namespace net