linux-kernel - Re: [patch] x86, pat: freeing invalid memtype messages

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Message-ID: <20100621185648.GA2768@joi.lan>
Date:	Mon, 21 Jun 2010 20:56:48 +0200
From:	Marcin Slusarz <marcin.slusarz@...il.com>
To:	Venkatesh Pallipadi <venki@...gle.com>
Cc:	Suresh Siddha <suresh.b.siddha@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Xiaotian Feng <dfeng@...hat.com>,
	Dan Carpenter <error27@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H.Peter Anvin" <hpa@...or.com>, Jack Steiner <steiner@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>
Subject: Re: [patch] x86, pat: freeing invalid memtype messages

On Mon, Jun 21, 2010 at 08:41:54PM +0200, Marcin Slusarz wrote:
> On Mon, Jun 21, 2010 at 11:38:27AM -0700, Venkatesh Pallipadi wrote:
> > On Mon, Jun 21, 2010 at 11:08 AM, Venkatesh Pallipadi <venki@...gle.com> wrote:
> > > On Mon, Jun 21, 2010 at 10:54 AM, Suresh Siddha
> > > <suresh.b.siddha@...el.com> wrote:
> > >> On Mon, 2010-06-21 at 08:41 -0700, Peter Zijlstra wrote:
> > >>> On Mon, 2010-06-21 at 17:33 +0200, Marcin Slusarz wrote:
> > >>> > On Mon, Jun 21, 2010 at 07:07:27PM +0800, Xiaotian Feng wrote:
> > >>> > > On 06/21/2010 07:02 PM, Peter Zijlstra wrote:
> > >>> > > > On Mon, 2010-06-21 at 18:56 +0800, Xiaotian Feng wrote:
> > >>> > > >
> > >>> > > >> I guess there might be something wrong between the augmented rbtree insert/remove ..
> > >>> > > >
> > >>> > > > The easiest thing is to revert that change and try again, the next step
> > >>> > > > would be to print the full RB tree on each modification and look where
> > >>> > > > it goes wrong.
> > >>> > > >
> > >>> > > > That said, I did print my fair share of (augmented) RB trees while
> > >>> > > > playing with scheduler patches and I can't remember it ever having
> > >>> > > > messed up like that.
> > >>> > > He's using 2.6.35-rc2+, without your "rbtree: Undo augmented trees
> > >>> > > performance damage" patch ;-)
> > >>> >
> > >>> > I applied it manually (commit 2463eb8b3093995e09a0d41b3d78ee0cf5fb4249 from -tip)
> > >>> > to 2.6.35-rc3 and it fixed both acpi's and nouveau's "invalid memtype" messages.
> > >>> > Thanks.
> > >>>
> > >>> Oh neat, so it actually fixes a bug in the previous augmented rb-tree
> > >>> implementation?
> > >>
> > >> When I was reviewing your fix, it looked like that prior to your fix we
> > >> were re-augmenting only at points where we do the tree rotations/color
> > >> change and at the points of node insertion/removal. I don't think we
> > >> were re-augmenting all the parent nodes in the path of the selected-node
> > >> that is going to replace the deleted node.
> > >>
> > >> Perhaps we were hitting this issue here.
> > >>
> > >
> > > rb_erase was calling the augment callback with successor_parent_cb.
> > > That should be doing proper re-augmenting on delete.
> > >
> > > May be we are hitting the problem with not-initializing
> > > subtree_max_end on insert? That was fixed in a later patch.
> > 
> > Here's the patch I was referring to
> > http://marc.info/?l=linux-mm-commits&m=127654225011850&w=2
> > 
> > Marcin: Can you try this patch without Peter's patch and see whether
> > there are any issues with that. Just to make sure we don't have issues
> > wuth underlying augmented rbtree algorithm that somehow got fixed or
> > masked for the time being with Peter's change.
> 
> I tested this patch few days ago and it produced even more "invalid memtype" messages...

http://kadu.net/~joi/kernel/2010.06.09/2.6.35-rc3-debugpat-x86-proper-init-of-memtype-subtree_max_end.txt

Marcin

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