feat(olp): add config and backoff gc

apps/emqx/src/emqx_channel.erl

@@ -1144,8 +1144,7 @@ run_terminate_hook(Reason, #channel{clientinfo = ClientInfo, session = Session})
 %% Internal functions
 %%--------------------------------------------------------------------
 overload_protection(_, #channel{clientinfo = #{zone := Zone}}) ->
-    T = get_mqtt_conf(Zone, overload_drawback_delay, 1),
+    emqx_olp:backoff(Zone),
-    emqx_olp:backoff(T),
     ok.
 
 %%--------------------------------------------------------------------

apps/emqx/src/emqx_connection.erl

@@ -821,8 +821,10 @@ ensure_rate_limit(Stats, State = #state{limiter = Limiter}) ->
 %%--------------------------------------------------------------------
 %% Run GC and Check OOM
 
-run_gc(Stats, State = #state{gc_state = GcSt}) ->
+run_gc(Stats, State = #state{gc_state = GcSt, zone = Zone}) ->
-    case ?ENABLED(GcSt) andalso emqx_gc:run(Stats, GcSt) of
+    case ?ENABLED(GcSt) andalso not emqx_olp:backoff_gc(Zone)
+        andalso emqx_gc:run(Stats, GcSt)
+    of
         false -> State;
         {_IsGC, GcSt1} ->
             State#state{gc_state = GcSt1}

apps/emqx/src/emqx_olp.erl

@@ -16,16 +16,35 @@
 -module(emqx_olp).
 -export([ is_overloaded/0
         , backoff/1
+        , backoff_gc/1
+        , backoff_hibernation/1
         ]).
 
 -spec is_overloaded() -> boolean().
 is_overloaded() ->
   load_ctl:is_overloaded().
 
--spec backoff(timer:timeout()) -> ok | timeout.
+-spec backoff(Zone :: atom()) -> ok | timeout.
-backoff(Delay) ->
+backoff(Zone) ->
-  load_ctl:maydelay(Delay).
+  case emqx_config:get_zone_conf(Zone, [overload_protection, enable], false) of
+    true ->
+      Delay = emqx_config:get_zone_conf(Zone, [overload_protection, backoff_delay], 1),
+      load_ctl:maydelay(Delay);
+    false ->
+      ok
+  end.
 
+-spec backoff_gc(Zone :: atom()) -> ok | timeout.
+backoff_gc(Zone) ->
+  load_ctl:is_overloaded()
+    andalso emqx_config:get_zone_conf(Zone, [overload_protection, enable], false)
+    andalso emqx_config:get_zone_conf(Zone, [overload_protection, backoff_gc], false).
+
+-spec backoff_hibernation(Zone :: atom()) -> ok | timeout.
+backoff_hibernation(Zone) ->
+  load_ctl:is_overloaded()
+    andalso emqx_config:get_zone_conf(Zone, [overload_protection, enable], false)
+    andalso emqx_config:get_zone_conf(Zone, [overload_protection, backoff_hibernation], false).
 %%%_* Emacs ====================================================================
 %%% Local Variables:
 %%% allout-layout: t

apps/emqx/src/emqx_schema.erl

@@ -122,6 +122,9 @@ roots(medium) ->
     , {"force_shutdown",
        sc(ref("force_shutdown"),
           #{})}
+    , {"overload_protection",
+       sc(ref("overload_protection"),
+          #{})}
     ];
 roots(low) ->
     [ {"force_gc",
@@ -323,7 +326,9 @@ fields("mqtt") ->
 
 fields("zone") ->
     Fields = ["mqtt", "stats", "flapping_detect", "force_shutdown",
-              "conn_congestion", "rate_limit", "quota", "force_gc"],
+              "conn_congestion", "rate_limit", "quota", "force_gc",
+              "overload_protection"
+             ],
     [{F, ref(emqx_zone_schema, F)} || F <- Fields];
 
 fields("rate_limit") ->
@@ -391,6 +396,24 @@ fields("force_shutdown") ->
            })}
     ];
 
+fields("overload_protection") ->
+    [ {"enable",
+       sc(boolean(),
+          #{ default => false})}
+    , {"backoff_delay",
+       sc(range(0, inf),
+          #{ default => 1
+           })}
+    , {"backoff_gc",
+       sc(boolean(),
+          #{ default => true
+           })}
+    , {"backoff_hibernation",
+       sc(boolean(),
+          #{ default => true
+           })}
+    ];
+
 fields("conn_congestion") ->
     [ {"enable_alarm",
        sc(boolean(),