From 81ed61b001a4476ceb84380ceb30e324df1c64c8 Mon Sep 17 00:00:00 2001
From: William Yang <mscame@gmail.com>
Date: Tue, 15 Mar 2022 11:39:23 +0100
Subject: [PATCH] feat: add load control app

---
 CHANGES-4.3.md      |  1 +
 rebar.config        |  1 +
 src/emqx.app.src    | 10 +++++++++-
 src/emqx_os_mon.erl | 11 ++++++++++-
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/CHANGES-4.3.md b/CHANGES-4.3.md
index 04447e220..11debe5e7 100644
--- a/CHANGES-4.3.md
+++ b/CHANGES-4.3.md
@@ -27,6 +27,7 @@ File format:
 * Add UTF-8 string validity check in `strict_mode` for MQTT packet.
   When set to true, invalid UTF-8 strings will cause the client to be disconnected. i.e. client ID, topic name. [#7261]
 * Changed systemd service restart delay from 10 seconds to 60 seconds.
+* Add load control app for future development.
 
 ### Bug fixes
 
diff --git a/rebar.config b/rebar.config
index 131aafebb..2003321bb 100644
--- a/rebar.config
+++ b/rebar.config
@@ -56,6 +56,7 @@
     , {observer_cli, "1.6.1"} % NOTE: depends on recon 2.5.1
     , {getopt, "1.0.1"}
     , {snabbkaffe, {git, "https://github.com/kafka4beam/snabbkaffe.git", {tag, "0.15.0"}}}
+    , {lc, {git, "https://github.com/emqx/lc.git", {tag, "0.2.0"}}}
     ]}.
 
 {xref_ignores,
diff --git a/src/emqx.app.src b/src/emqx.app.src
index 66ab590ca..2f58c52a8 100644
--- a/src/emqx.app.src
+++ b/src/emqx.app.src
@@ -9,7 +9,15 @@
   {vsn, "4.3.14"}, % strict semver, bump manually!
   {modules, []},
   {registered, []},
-  {applications, [kernel,stdlib,gproc,gen_rpc,esockd,cowboy,sasl,os_mon]},
+  {applications, [ kernel
+                 , stdlib
+                 , gproc
+                 , gen_rpc
+                 , esockd
+                 , cowboy
+                 , sasl
+                 , lc
+                 , os_mon]},
   {mod, {emqx_app,[]}},
   {env, []},
   {licenses, ["Apache-2.0"]},
diff --git a/src/emqx_os_mon.erl b/src/emqx_os_mon.erl
index e7565947c..a8419bc82 100644
--- a/src/emqx_os_mon.erl
+++ b/src/emqx_os_mon.erl
@@ -48,6 +48,7 @@
         ]).
 
 -include("emqx.hrl").
+-include_lib("lc/include/lc.hrl").
 
 -define(OS_MON, ?MODULE).
 
@@ -88,7 +89,15 @@ get_sysmem_high_watermark() ->
     memsup:get_sysmem_high_watermark().
 
 set_sysmem_high_watermark(Float) ->
-    memsup:set_sysmem_high_watermark(Float / 100).
+    V = Float/100,
+    case load_ctl:get_config() of
+        #{ ?MEM_MON_F0 := true } = OldLC ->
+            ok = load_ctl:put_config(OldLC#{ ?MEM_MON_F0 => true
+                                           , ?MEM_MON_F1 => V});
+        _ ->
+            skip
+    end,
+    memsup:set_sysmem_high_watermark(V).
 
 get_procmem_high_watermark() ->
     memsup:get_procmem_high_watermark().