Re: 2.6.29 git master and PAT problems

From: Arkadiusz Miskiewicz
Date: Tue Apr 07 2009 - 05:14:30 EST

On Tuesday 07 of April 2009, Pallipadi, Venkatesh wrote:
> On Thu, 2009-04-02 at 00:12 -0700, Arkadiusz Miskiewicz wrote:
> > On Thursday 02 of April 2009, Pallipadi, Venkatesh wrote:
> > > On Mon, Mar 30, 2009 at 05:28:15PM -0700, Pallipadi, Venkatesh wrote:
> > > > On Mon, Mar 30, 2009 at 03:31:09PM -0700, Arkadiusz Miskiewicz wrote:
> > > > > On Monday 30 of March 2009, Pallipadi, Venkatesh wrote:
> > > > >
> > > > > More info follows. Now I've switched to
> > > > > e1c502482853f84606928f5a2f2eb6da1993cda1 which contains latest drm
> > > > > fixes and now I get much lower numbers of PAT errors but still.
> > > > >
> > > > > > On Mon, 2009-03-30 at 14:31 -0700, Arkadiusz Miskiewicz wrote:
> > > > > > > On Monday 30 of March 2009, Pallipadi, Venkatesh wrote:
> > > > > > > > Patch here should get rid of these errors.
> > > > > > > >
> > > > > > > > http://marc.info/?l=linux-kernel&m=123788806506230&w=2
> > > > > > > >
> > > > > > > > The patch is in tip and on its way to upstream.
> > > > > > >
> > > > > > > The problem is that kernel I'm running already contains this
> > > > > > > patch (it's merged already). Other ideas?
> > > > > > >
> > > > > > > ratelimiting that error is good IMO anyway.
> > > > > >
> > > > > > Rate limiting will just work around the problem here. Ideally we
> > > > > > should never see these errors. So, it will be better if we can
> > > > > > narrow down on the bug resulting in these error messages.
> > > > >
> > > > > Of course it's better. I'm saying that when these messages "fire"
> > > > > then it's hard to do anything else on the system for a while until
> > > > > these stop.
> > > > >
> > > > > > Can you please send me the output of
> > > > > > # cat /debug/x86/pat_memtype_list
> > > > > > with debugfs mounted.
> > > > > > and
> > > > > > # cat /proc/mtrr
> > > >
> > > > There seems to be two different problems here.
> > > > - We should not have that many single page ranges reserved. That will
> > > > cause a performance problem with drm even without the "freeing
> > > > invalid type" error. - "freeing invalid type" error itself. Seems to
> > > > be caused due to some unbalanced free along the drm path. We tried to
> > > > find anything obvious in the code that may be causing problem here.
> > > > But, haven't found anything so far. Will try to reproduce the problem
> > > > internally and debug it further.
> > >
> > > OK. I think we have root caused the thinko that was resulting in
> > > "freeing invalid type" error. Can you try the below test
> > > patch. Patch is not final version and may need some cleanup.
> >
> > Was testing on linus git as of today +
> > [PATCH] x86, PAT: Remove duplicate memtype reserve in pci mmap
> > + patch from this thread.
> >
> > It doesn't fix the problem. At least I'm able to reproduce "Freeint
> > invalid memtype" by just running http://www.tremulous.net/ game. It also
> > happened when watching youtube with opera. _Maybe_ things are little
> > better because number of "freeing invalid memtype" messages is much lower
> > than before but there is posibility that I simply didn't trigger it
> > fully.
>
> Arkadiusz,
>
> I was finally able to reproduce the problem of "freeing invalid memtype"
> with upstream git kernel (commit 0221c81b1b) + latest xf86 intel driver.
> But, with upstream + the patch I had sent you earlier in this thread
> (http://marc.info/?l=linux-kernel&m=123863345520617&w=2) I don't see
> those freeing invalid memtype errors anymore.
>
> Can you please double check with current git and that patch and let me
> know if you are still seeing the problem.

Latest linus tree + that patch (it's really applied here), xserver 1.6, libdrm
from git master, intel driver from git master, previously mesa 7.4 (and 7.5
snap currently), tremolous.net 1.1.0 game (tremolous-smp binary), GM45 gpu.

To reproduce I just need to run tremolous-smp and connect to some map. When
map finishes loading I instantly get:

1 [ 132.341378] tremulous-smp:5554 freeing invalid memtype d570d000-
d570e000
1 [ 132.341394] tremulous-smp:5554 freeing invalid memtype d570e000-
d570f000
1 [ 132.341409] tremulous-smp:5554 freeing invalid memtype d570f000-
d5710000
1 [ 139.323677] X:5238 freeing invalid memtype d6168000-d6169000
1 [ 139.323698] X:5238 freeing invalid memtype d6169000-d616a000
1 [ 139.323722] X:5238 freeing invalid memtype d616a000-d616b000
1 [ 139.323742] X:5238 freeing invalid memtype d616b000-d616c000

$ dmesg|grep "freeing invalid" | wc -l
6643

> Thanks,
> Venki

--
Arkadiusz Miśkiewicz PLD/Linux Team
arekm / maven.pl http://ftp.pld-linux.org/

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