Limit the number of UL buffers in MAC and deallocate old ones

srsenb/hdr/stack/mac/ue.h

@@ -15,6 +15,7 @@
 
 #include "mac_metrics.h"
 #include "srslte/common/block_queue.h"
+#include "srslte/adt/circular_array.h"
 #include "srslte/common/log.h"
 #include "srslte/common/mac_pcap.h"
 #include "srslte/interfaces/enb_interfaces.h"
@@ -71,10 +72,10 @@ public:
   srslte_softbuffer_rx_t* get_rx_softbuffer(const uint32_t ue_cc_idx, const uint32_t tti);
 
   bool     process_pdus();
-  uint8_t* request_buffer(const uint32_t len);
+  uint8_t* request_buffer(uint32_t tti, const uint32_t len);
   void     process_pdu(uint8_t* pdu, uint32_t nof_bytes, srslte::pdu_queue::channel_t channel) override;
-  void     push_pdu(const uint8_t* pdu_ptr, uint32_t len);
+  void     push_pdu(uint32_t tti, const uint8_t* pdu_ptr, uint32_t len);
-  void     deallocate_pdu(const uint8_t* pdu_ptr);
+  void     deallocate_pdu(uint32_t tti, const uint8_t* pdu_ptr);
 
   void metrics_read(mac_ue_metrics_t* metrics_);
   void metrics_rx(bool crc, uint32_t tbs);
@@ -122,6 +123,9 @@ private:
   std::vector<std::array<std::array<srslte::unique_byte_buffer_t, SRSLTE_MAX_TB>, SRSLTE_FDD_NOF_HARQ> >
       tx_payload_buffer;
 
+  // Save 2 buffers per HARQ process
+  srslte::circular_array<uint8_t*, 2 * SRSLTE_FDD_NOF_HARQ> rx_used_buffers;
+
   srslte::block_queue<uint32_t> pending_ta_commands;
   ta                            ta_fsm;
 

srsenb/src/stack/mac/mac.cc

@@ -334,11 +334,11 @@ int mac::push_pdu(uint32_t tti_rx, uint16_t rnti, const uint8_t* pdu_ptr, uint32
   // push the pdu through the queue if received correctly
   if (crc) {
     Info("Pushing PDU rnti=0x%x, tti_rx=%d, nof_bytes=%d\n", rnti, tti_rx, nof_bytes);
-    ue_db[rnti]->push_pdu(pdu_ptr, nof_bytes);
+    ue_db[rnti]->push_pdu(tti_rx, pdu_ptr, nof_bytes);
     stack_task_queue.push([this]() { process_pdus(); });
   } else {
     Debug("Discarting PDU rnti=0x%x, tti_rx=%d, nof_bytes=%d\n", rnti, tti_rx, nof_bytes);
-    ue_db[rnti]->deallocate_pdu(pdu_ptr);
+    ue_db[rnti]->deallocate_pdu(tti_rx, pdu_ptr);
   }
   return SRSLTE_SUCCESS;
 }
@@ -906,7 +906,7 @@ int mac::get_ul_sched(uint32_t tti_tx_ul, ul_sched_list_t& ul_sched_res_list)
             if (sched_result.pusch[n].current_tx_nb == 0) {
               srslte_softbuffer_rx_reset_tbs(phy_ul_sched_res->pusch[n].softbuffer_rx, sched_result.pusch[i].tbs * 8);
             }
-            phy_ul_sched_res->pusch[n].data = ue_db[rnti]->request_buffer(sched_result.pusch[i].tbs);
+            phy_ul_sched_res->pusch[n].data = ue_db[rnti]->request_buffer(tti_tx_ul, sched_result.pusch[i].tbs);
             if (phy_ul_sched_res->pusch[n].data) {
               phy_ul_sched_res->nof_grants++;
             } else {

srsenb/src/stack/mac/ue.cc

@@ -161,14 +161,27 @@ ue::get_tx_softbuffer(const uint32_t ue_cc_idx, const uint32_t harq_process, con
   return &softbuffer_tx.at(ue_cc_idx).at((harq_process * SRSLTE_MAX_TB + tb_idx) % nof_tx_harq_proc);
 }
 
-uint8_t* ue::request_buffer(const uint32_t len)
+uint8_t* ue::request_buffer(uint32_t tti, const uint32_t len)
 {
+  uint8_t* pdu = nullptr;
   if (len > 0) {
-    return pdus.request(len);
+    pdu = pdus.request(len);
+    if (pdu) {
+      // Deallocate oldest buffer if we didn't deallocate it
+      if (rx_used_buffers[tti] != nullptr) {
+        pdus.deallocate(rx_used_buffers[tti]);
+        rx_used_buffers[tti] = nullptr;
+        log_h->warning("buffers: RX PDU of rnti=0x%x and pid=%d wasn't deallocated\n", rnti, tti % nof_rx_harq_proc);
+      }
+      rx_used_buffers[tti] = pdu;
+      log_h->info("RX PDU saved for pid=%d\n", tti % nof_rx_harq_proc);
+    } else {
+      log_h->error("buffers: Requesting buffer from pool\n");
+    }
   } else {
-    log_h->warning("Requesting buffer for zero bytes\n");
+    printf("buffers: Requesting buffer for zero bytes\n");
-    return nullptr;
   }
+  return pdu;
 }
 
 bool ue::process_pdus()
@@ -293,18 +306,28 @@ void ue::process_pdu(uint8_t* pdu, uint32_t nof_bytes, srslte::pdu_queue::channe
   Debug("MAC PDU processed\n");
 }
 
-void ue::deallocate_pdu(const uint8_t* pdu_ptr)
+void ue::deallocate_pdu(uint32_t tti, const uint8_t* pdu_ptr)
 {
   if (pdu_ptr) {
+    if (rx_used_buffers[tti] == pdu_ptr) {
+      rx_used_buffers[tti] = nullptr;
+    } else {
+      Warning("buffers: Unexpected RX PDU pointer in deallocate_pdu for rnti=0x%x pid=%d\n", rnti, tti % nof_rx_harq_proc);
+    }
     pdus.deallocate(pdu_ptr);
   } else {
     Error("Error deallocating PDU: null ptr\n");
   }
 }
 
-void ue::push_pdu(const uint8_t* pdu_ptr, uint32_t len)
+void ue::push_pdu(uint32_t tti, const uint8_t* pdu_ptr, uint32_t len)
 {
   if (pdu_ptr && len > 0) {
+    if (rx_used_buffers[tti] == pdu_ptr) {
+      rx_used_buffers[tti] = nullptr;
+    } else {
+      Warning("buffers: Unexpected RX PDU pointer in push_pdu for rnti=0x%x pid=%d\n", rnti, tti % nof_rx_harq_proc);
+    }
     pdus.push(pdu_ptr, len);
   } else {
     Error("Error pushing PDU: ptr=%p, len=%d\n", pdu_ptr, len);