Re: Bisecting tip/auto-x86-next?

Kevin Winchester
2008-06-21T10:23:23Z

On Sat, Jun 21, 2008 at 7:18 AM, Yinghai Lu <yhlu.kernel@gmail.com> wrote:
> On Sat, Jun 21, 2008 at 3:00 AM, Kevin Winchester
> <kjwinchester@gmail.com> wrote:
>> Yinghai Lu wrote:
>>>
>>> On Fri, Jun 20, 2008 at 5:00 PM, Kevin Winchester
>>> <kjwinchester@gmail.com> wrote:
>>>>
>>>> Ingo Molnar wrote:
>>>>>
>>>>> * Kevin Winchester <kjwinchester@gmail.com> wrote:
>>>>>
>>>>>>> hm, could you send me the config that triggered this?
>>>>>>
>>>>>> I will do so tonight when I am home again. It is a UP AMD64 box with a
>>>>>> VIA chipset, if that helps.
>>>>>>
>>>>>>> btw., you can probably ignore this one safely. Also please tell me at
>>>>>>> which commit ID you were at when you triggered this warning.
>>>>>>
>>>>>> Good to know - I will get the commit ID tonight as well, although
>>>>>> wouldn't following the same bisection sequence that I did give you the
>>>>>> same
>>>>>> bisection point? I guess that would assume that linus/master and
>>>>>> auto-x86-next haven't changed much since last night, which might not be
>>>>>> correct.
>>>>>
>>>>> yeah, you'd probably not hit that warning with the x86/gart bisection
>>>>> sequence. (Assuming the bug is introduced in that branch - so you should
>>>>> first check whether pure x86/gart kernel triggers the problem too.)
>>>>>
>>>>> If you still have the commit ID around then please send it - if you
>>>>> dont,
>>>>> no problem, it's no big issue. I wanted to check how wide the bisection
>>>>> window is where the warning triggers.
>>>>>
>>>> I'm sorry - I accidentally checkout out x86/gart to test it before
>>>> grabbing
>>>> the commit ID.
>>>>
>>>> I went ahead with the bisection and found:
>>>>
>>>>
>>>>
>>>> 8c9fd91a0dc503f085169d44f4360be025f75224 is first bad commit
>>>> commit 8c9fd91a0dc503f085169d44f4360be025f75224
>>>> Author: Yinghai Lu <yhlu.kernel@gmail.com>
>>>> Date: Sun Apr 13 18:42:31 2008 -0700
>>>>
>>>> x86: checking aperture size order
>>>>
>>>> some systems are using 32M for gart and agp when memory is less than
>>>> 4G.
>>>> Kernel will reject and try to allcate another 64M that is not needed,
>>>> and we will waste 64M of perfectly good RAM.
>>>>
>>>> this patch adds a workaround by checking aper_base/order between NB and
>>>> agp bridge. If they are the same, and memory size is less than 4G, it
>>>> will allow it.
>>>>
>>>> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
>>>> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>>>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>>>>
>>>> :040000 040000 848d6e4045a14d01fc0a794d4350d8a84f3ceff6
>>>> 4a10a52b41309060cd5dc1bf0c322f6d43b2477b M arch
>>>> :040000 040000 aa1cee87b1f5b1b30ed03ce6164ad7f404fef2a3
>>>> f9ce0aaa1f7d4fdc7bdc5a43285495db53a6f531 M drivers
>>>>
>>>>
>>>> as the first bad commit. I do not have time to look at the patch right
>>>> now,
>>>> but in case anyone else does, I figured I would post it.
>>>>
>>>
>>> please send out whole boot logs with "debug" in command line.
>>>
>>
>> "debug" in the command line doesn't seem to have any effect on the printout
>> (is there some config option I need to use with it?), but here it is anyway:
>
> are you using tip/master?
>
> http://people.redhat.com/mingo/sched-devel.git/README
>

That log is from tip/x86/gart, which is where the problem patch was
bisected. Would you get better debugging info from tip/master (which
includes tip/x86/gart, I believe, and thus would show the problem as
well)?

--
Kevin Winchester