Re: [PATCH] mm: remove zone->prev_prioriy

Andrew Morton
2009-02-10T23:13:15Z

On Tue, 10 Feb 2009 19:57:01 +0900
MinChan Kim <minchan.kim@gmail.com> wrote:

> As you know, prev_priority is used as a measure of how much stress page reclaim.
> But now we doesn't need it due to split-lru's way.
>
> I think it would be better to remain why prev_priority isn't needed any more
> and how split-lru can replace prev_priority's role in changelog.
>
> In future, it help mm newbies understand change history, I think.

Yes, I'd be fascinated to see that explanation.

In http://groups.google.pn/group/linux.kernel/browse_thread/thread/fea9c9a0b43162a1
it was asserted that we intend to use prev_priority again in the future.

We discussed this back in November:
http://lkml.indiana.edu/hypermail/linux/kernel/0811.2/index.html#00001

And I think that I still think that the VM got worse due to its (new)
failure to track previous state. IIRC, the response to that concern
was quite similar to handwavy waffling.