那要看先行词是指什么。

1. 若指物，则其后通常是要用 that 来引导定语从句。如：

He took all that I had. 他我所有的都拿去了。

All that needs to be done has been done. 该干的都干完了。

All that glitters is not gold. 闪光的东西不都是金子。

All that matters is to be happy. 最重要的是要心情愉快。

2. 若先行词指人，则完全可以用 who 来引导定语从句。如：

He was a man who was beloved by all who knew him. 每一个认识他的人都敬重他。

Health care must be at the service of all who need it.  医疗保健机构必须为所有需要者提供服务。