move lua ui-related data to spi ram

lib/luavgl/src/event.c

@@ -1,6 +1,8 @@
 #include "luavgl.h"
 #include "private.h"
 
+#include "esp_heap_caps.h"
+
 static void luavgl_obj_event_cb(lv_event_t *e)
 {
   lua_State *L = e->user_data;
@@ -102,7 +104,8 @@ static int luavgl_obj_on_event(lua_State *L)
   /* create obj->lobj->events, if NULL, realloc if existing and find no slot
    */
   if (events == NULL) {
-    events = calloc(sizeof(struct event_callback_s), 1);
+    events =
+        heap_caps_calloc(sizeof(struct event_callback_s), 1, MALLOC_CAP_SPIRAM);
     if (events == NULL) {
       return luaL_error(L, "No memory.");
     }
@@ -113,7 +116,9 @@ static int luavgl_obj_on_event(lua_State *L)
     /* realloc? */
     if (slot && slot == lobj->n_events) {
       struct event_callback_s *_events;
-      _events = realloc(lobj->events, (lobj->n_events + 1) * sizeof(*_events));
+      _events = heap_caps_realloc(lobj->events,
+                                  (lobj->n_events + 1) * sizeof(*_events),
+                                  MALLOC_CAP_SPIRAM);
       if (_events == NULL) {
         return luaL_error(L, "No memory.");
       }

src/ui/ui_fsm.cpp

@@ -7,6 +7,7 @@
 #include "ui_fsm.hpp"
 
 #include <memory>
+#include <memory_resource>
 #include <variant>
 
 #include "bluetooth_types.hpp"
@@ -26,6 +27,7 @@
 #include "lauxlib.h"
 #include "lua_thread.hpp"
 #include "luavgl.h"
+#include "memory_resource.hpp"
 #include "misc/lv_gc.h"
 
 #include "audio_events.hpp"
@@ -449,8 +451,12 @@ auto Lua::PushLuaScreen(lua_State* s) -> int {
   luaL_checktype(s, 1, LUA_TFUNCTION);
 
   // First, create a new plain old Screen object. We will use its root and
-  // group for the Lua screen.
+  // group for the Lua screen. Allocate it in external ram so that arbitrarily
-  auto new_screen = std::make_shared<screens::Lua>();
+  // deep screen stacks don't cause too much memory pressure.
+  auto new_screen =
+      std::allocate_shared<screens::Lua,
+                           std::pmr::polymorphic_allocator<screens::Lua>>(
+          &memory::kSpiRamResource);
 
   // Tell lvgl about the new roots.
   luavgl_set_root(s, new_screen->content());