diff --git a/source/blender/blenkernel/intern/undo_system.cc b/source/blender/blenkernel/intern/undo_system.cc
index 1fce7d6500c..c2bffa423d4 100644
--- a/source/blender/blenkernel/intern/undo_system.cc
+++ b/source/blender/blenkernel/intern/undo_system.cc
@@ -384,7 +384,7 @@ UndoStep *BKE_undosys_stack_init_or_active_with_type(UndoStack *ustack, const Un
 void BKE_undosys_stack_limit_steps_and_memory(UndoStack *ustack, int steps, size_t memory_limit)
 {
   UNDO_NESTED_ASSERT(false);
-  if ((steps == -1) && (memory_limit != 0)) {
+  if ((steps == -1) && (memory_limit == 0)) {
     return;
   }
 
@@ -398,6 +398,12 @@ void BKE_undosys_stack_limit_steps_and_memory(UndoStack *ustack, int steps, size
     if (memory_limit) {
       data_size_all += us->data_size;
       if (data_size_all > memory_limit) {
+        CLOG_INFO(&LOG,
+                  1,
+                  "At step %zu: data_size_all=%zu >= memory_limit=%zu",
+                  us_count,
+                  data_size_all,
+                  memory_limit);
         break;
       }
     }
@@ -411,6 +417,8 @@ void BKE_undosys_stack_limit_steps_and_memory(UndoStack *ustack, int steps, size
     }
   }
 
+  CLOG_INFO(&LOG, 1, "Total steps %zu: data_size_all=%zu", us_count, data_size_all);
+
   if (us) {
 #ifdef WITH_GLOBAL_UNDO_KEEP_ONE
     /* Hack, we need to keep at least one BKE_UNDOSYS_TYPE_MEMFILE. */