keira: add smart memory allocator for Lua that uses PSRAM if internal…

… RAM usage is too high

firmware/keira/src/apps/lua/luarunner.cpp

@@ -96,10 +96,30 @@ AbstractLuaRunnerApp::AbstractLuaRunnerApp(const char* appName) :
     setFlags(AppFlags::APP_FLAG_FULLSCREEN);
 }
 
+void* lua_smart_alloc(void* ud, void* ptr, size_t osize, size_t nsize) {
+    // If there will be less than 32 KB of free RAM after reallocating, use PSRAM allocator.
+    (void)ud;
+    (void)osize;
+    int32_t free_mem = heap_caps_get_free_size(MALLOC_CAP_8BIT);
+    if (nsize) {
+        uint32_t caps = MALLOC_CAP_8BIT;
+        if (free_mem - nsize < 32 * 1024) {
+            // Less than 32 KB of free RAM after reallocating. Use PSRAM allocator.
+            caps |= MALLOC_CAP_SPIRAM;
+        } else {
+            // More than 32 KB of free RAM after reallocating. Use regular allocator.
+        }
+        return heap_caps_realloc(ptr, nsize, caps);
+    } else {
+        free(ptr);
+        return NULL;
+    }
+}
+
 void AbstractLuaRunnerApp::luaSetup(const char* dir) {
     lilka::serial_log("lua: script dir: %s", dir);
 
-    L = luaL_newstate();
+    L = lua_newstate(lua_smart_alloc, NULL);
 
     lilka::serial_log("lua: init libs");
     luaL_openlibs(L);