Re: please revert bogus patch to vmscan.c

Benjamin LaHaise
2001-10-30T01:48:40Z

On Mon, Oct 29, 2001 at 05:34:00PM -0800, David S. Miller wrote:
> I'm asking him to show the case that "breaks for something
> else".

Why don't you try lifting your fingers to defend your position? We know
that:

1. the change introduces state data to tlb with no limits on the
duration of said stale data
2. some architectures have large tlbs.

For the sake of (2), hashed tlbs count as excessively large tlbs. See the
UML, ia64 and powerpcs for this kind of setup.

Now, if you want to live in microbenchmark land, then, yes, the "optimized"
but invalid behaviour will *always* win. Back in the real world, sure, I can
construct a microbenchmark that will sit on 2 pages of memory spinning until
the pages get swapped out. What does that buy us? Nothing other than
placating you.

I've already pointed out that the optimization can be done in a valid way. If
you can't go through the effort of completing the above thought experiment on
your own, then I really have no reason to care about your opinion any further.
You've already stated you don't care about mine, and I've stated that I don't
feel like going to the effort to placate you. Where does that leave us?
Nowhere, I guess.

-ben