Re: [regression] commit 6a4f3b52 causes invalid memtype

From: Ingo Molnar
Date: Mon Jul 05 2010 - 08:46:38 EST



* Ali Gholami Rudi <ali@xxxxxxx> wrote:

> Ingo Molnar <mingo@xxxxxxx> wrote:
> > > > >> commit 2463eb8b3093995e09a0d41b3d78ee0cf5fb4249
> > > > >> Author: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
> > > > >> Date: Sat May 29 15:31:43 2010 +0200
> > > > >>
> > > > >> rbtree: Undo augmented trees performance damage
> > > > >
> > > > > Where can I get it? I couldn't find it either in
> > > > > Linus' or x86 repo tip.
> > > > http://git.kernel.org/tip/2463eb8b3093995e09a0d41b3d78ee0cf5fb4249
> > >
> > > It does fix it.
> >
> > Hm, interesting. That's a pure performance fix - so why does it fix a
> > regression?
> >
> > Does Peter's augmented rbtrees improvements fix a bug too, as a side-effect?
> > If yes then we need to accelerate that commit - right now it's aimed for
> > v2.6.36.
>
> Since the bug appears after commit 6a4f3b52, it seems to be
> related to the value of memtype->subtree_max_end. Peter's
> patch seems to change the way memtype->subtree_max_end is
> updated, which seems to fix the problem too.

Ok - i've cherry-picked it over into x86/urgent and it should go to Linus in
the next round of x86 fixes.

Thanks,

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/