Re: [patch 0/4] mm: de-skew page refcount

From: Nick Piggin
Date: Thu Jan 19 2006 - 12:36:51 EST


On Thu, Jan 19, 2006 at 09:27:14AM -0800, Linus Torvalds wrote:
>
>
> On Thu, 19 Jan 2006, Nick Piggin wrote:
> >
> > Hmm... this is what the de-skew patch _did_ (although it was wrapped
> > in a function called get_page_unless_zero), in fact the main aim was
> > to prevent this twiddling and the de-skewing was just a nice side effect
> > (I guess the patch title is misleading).
> >
> > So I'm confused...
>
> The thing I minded was the _other_ changes, namely the de-skewing itself.
> It seemed totally unnecessary to what you claimed was the point of the
> patch.
>
> So I objected to the patch on the grounds that it did what you claimed
> badly. All the _optimization_ was totally independent of that de-skewing,
> and the de-skewing was a potential un-optimization.
>

No longer confused...

> But if you do the optimizations as one independent set of patches, and
> _then_ do the counter thing as a "simplify logic" patch, I don't see that
> as a problem.
>
> Side note: I may be crazy, but for me when merging, one of the biggest
> things is "does this pass my 'makes sense' detector". I look less at the
> end result, than I actually look at the _change_. See?
>
> That's why two separate patches that do the same thing as one combined
> patch may make sense, even if the _combined_ one does not (it could go the
> other way too, obviously).
>

I agree, and the patches really are cleaner this way too, so again,
thanks for the input on them.

I'll resend soonish (with a trimmed cc list).

Nick
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