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

Andrew Morton
2005-09-02T02:30:34Z

Andi Kleen <ak@suse.de> wrote:
>
> On Friday 02 September 2005 04:08, Andrew Morton wrote:
>
> > I suppose I'll queue it up in -mm for a while, although I'm a bit dubious
> > about the whole idea... We'll gain some and we'll lose some - how do we
> > know it's a net gain?
>
> I suspect it'll gain more than it loses. The only case where it might
> not gain is immediately someone reading the data from the page cache again
> after the write.

That's a pretty common case - temporary files.

> But I suppose that's far less frequent than writing the data.

yup.

Hiro, could you please send through a summary of the performance testing
results sometime? Runtimes rather than oprofile output?