feat: set accessed bit to allocated frames in page_load and get_usr_kpage

src/userprog/process.c

@@ -811,6 +811,7 @@ get_usr_kpage (enum palloc_flags flags, void *upage)
     return NULL;
   else
     page = frame_alloc (flags, upage, t);
+  pagedir_set_accessed (t->pagedir, upage, true);
 #else
   page = palloc_get_page (flags | PAL_USER);
 #endif