Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()

Christoph Hellwig
2005-08-14T10:45:35Z

> the problem is that the pay elsewhere is far more spread out, but not
> less. At least generally....
>
> I can see the point of a copy_from_user_nocache() or something, for
> those cases where we *know* we are not going to use the copied data in
> the cpu (but say, only do DMA).
> But that should be explicit, not implicit, since the general case will
> be that the kernel WILL use the data.

Most of the callers probably want the normal one, but most of the copied
data (buffered filesystem I/O) will want the non cache poluting one.

So yes, doing this explicit makes a lot of sense.