PsSetProcessPriorityByClass

VOID __fastcall PsSetProcessPriorityByClass(INT64 a1, INT64 a2){
  if( (_DWORD)a2 == 2 )
    PspSetProcessPriorityByClass(a1, 2i64);
  else
    PspSetProcessForegroundBackgroundRequest(a1, (_DWORD)a2 == 1, 0);
}

Referenced by:

NtSetInformationProcess