Handling buffer model change gracefully

cfgmgr/buffermgr.cpp

@@ -30,6 +30,7 @@ BufferMgr::BufferMgr(DBConnector *cfgDb, DBConnector *applDb, string pg_lookup_f
         m_applBufferEgressProfileListTable(applDb, APP_BUFFER_PORT_EGRESS_PROFILE_LIST_NAME)
 {
     readPgProfileLookupFile(pg_lookup_file);
+    dynamic_buffer_model = false;
 }
 
 //# speed, cable, size,    xon,  xoff, threshold,  xon_offset
@@ -273,12 +274,62 @@ void BufferMgr::doBufferTableTask(Consumer &consumer, ProducerStateTable &applTa
     }
 }
 
+void BufferMgr::doBufferMetaTask(Consumer &consumer)
+{
+    SWSS_LOG_ENTER();
+
+    auto it = consumer.m_toSync.begin();
+    while (it != consumer.m_toSync.end())
+    {
+        KeyOpFieldsValuesTuple t = it->second;
+        string key = kfvKey(t);
+
+        string op = kfvOp(t);
+        if (op == SET_COMMAND)
+        {
+            vector<FieldValueTuple> fvVector;
+
+            for (auto i : kfvFieldsValues(t))
+            {
+                if (fvField(i) == "buffer_model")
+                {
+                    if (fvValue(i) == "dynamic")
+                    {
+                        dynamic_buffer_model = true;
+                    }
+                    else
+                    {
+                        dynamic_buffer_model = false;
+                    }
+                    break;
+                }
+            }
+        }
+        else if (op == DEL_COMMAND)
+        {
+            dynamic_buffer_model = false;
+        }
+        it = consumer.m_toSync.erase(it);
+    }
+}
+
 void BufferMgr::doTask(Consumer &consumer)
 {
     SWSS_LOG_ENTER();
 
     string table_name = consumer.getTableName();
 
+    if (table_name == CFG_DEVICE_METADATA_TABLE_NAME)
+    {
+        doBufferMetaTask(consumer);
+        return;
+    }
+
+    if (dynamic_buffer_model)
+    {
+         SWSS_LOG_DEBUG("Dynamic buffer model enabled. Skipping further processing");
+         return;
+    }
     if (table_name == CFG_BUFFER_POOL_TABLE_NAME)
     {
         doBufferTableTask(consumer, m_applBufferPoolTable);

cfgmgr/buffermgr.h

@@ -50,6 +50,7 @@ class BufferMgr : public Orch
     ProducerStateTable m_applBufferEgressProfileListTable;
 
     bool m_pgfile_processed;
+    bool dynamic_buffer_model;
 
     pg_profile_lookup_t m_pgProfileLookup;
     port_cable_length_t m_cableLenLookup;
@@ -63,6 +64,7 @@ class BufferMgr : public Orch
     void transformSeperator(std::string &name);
 
     void doTask(Consumer &consumer);
+    void doBufferMetaTask(Consumer &consumer);
 };
 
 }

cfgmgr/buffermgrd.cpp

@@ -195,7 +195,8 @@ int main(int argc, char **argv)
                 CFG_BUFFER_PG_TABLE_NAME,
                 CFG_BUFFER_QUEUE_TABLE_NAME,
                 CFG_BUFFER_PORT_INGRESS_PROFILE_LIST_NAME,
-                CFG_BUFFER_PORT_EGRESS_PROFILE_LIST_NAME
+                CFG_BUFFER_PORT_EGRESS_PROFILE_LIST_NAME,
+                CFG_DEVICE_METADATA_TABLE_NAME
             };
             cfgOrchList.emplace_back(new BufferMgr(&cfgDb, &applDb, pg_lookup_file, cfg_buffer_tables));
         }

tests/test_buffer_mode.py

@@ -1,7 +1,20 @@
 import pytest
+import time
 
 class TestBufferModel(object):
     def test_bufferModel(self, dvs, testlog):
         config_db = dvs.get_config_db()
         metadata = config_db.get_entry("DEVICE_METADATA", "localhost")
         assert metadata["buffer_model"] == "traditional"
+
+    def test_update_bufferModel(self, dvs, testlog):
+        config_db = dvs.get_config_db()
+        app_db = dvs.get_app_db()
+        keys = app_db.get_keys("BUFFER_POOL_TABLE")
+        num_keys =  len(keys)
+        fvs = {'buffer_model' : 'dynamic'}
+        config_db.update_entry("DEVICE_METADATA", "localhost", fvs)
+        fvs = {'mode':'dynamic', 'type':'egress'}
+        config_db.update_entry("BUFFER_POOL", "temp_pool", fvs)
+        time.sleep(2)
+        app_db.wait_for_n_keys("BUFFER_POOL_TABLE", num_keys)