Re: komd issues - was [Re: [openMosix-general] openmosix 2.4.26 in 2.4.31?]

Florian Delizy <[email protected]> Thu, 21 Sep 2006 20:13:12 +0200
Newsgroups gmane.linux.cluster.openmosix.devel
Message-ID <[email protected]>
Matt Dew wrote:
> Setting LD_ASSUME_KERNEL=2.4.1 fixes the system call segfaults.
> WOOHOO!! Now we know where to look to fix the problem.
>
>   
Do you mean you need to set the variable LD_ASSUME_KERNEL before calling 
insmod ? or something like that ?? or to set the LD_ASSUME_KERNEL 
variable before starting (and/or) migrating a process ?
> Unfortunately, I don't really understand LD_ASSUME_KERNEL in great
> detail.  
>   
AFAIK, it's something that tells the dynamic linker not to load a shared 
object if the version of the kernel is less than what's in this flag ...
> Are we going to have to redo the sys_call_table?  Have each entry call a
> new om_sys_call_table that calls the appropriate function?
>   
What's the link between LD_ASSUME_KERNEL and the syscall table ?
> Matt
>
> On Wed, 2006-09-20 at 13:02 +0000, "Matt Dew"  wrote:
>   
>> Hi Ian,
>>   I wish I could narrow it down, but unfortunately I don't know where
>> the bug is.  The best I can do is to refer you to Florian's patches or
>> the big patch itself, 
>> (against vanilla kernel)
>> http://osource.org/openmosix/patches/om-2.6.17-full-20060831.patch.bz2
>>     
>  
>   
>> (against git tree)
>> http://osource.org/openmosix/patches/om-2.6.17-git-20060831.patch.bz2
>>
>>
>> As the bug doesn't happen for every migrated process my current
>>     
> thinking
>   
>> is that when a process is migrated and kcomd creates a new process the
>> task_struct slab that is allocated isn't correctly initialized and
>>     
> only
>   
>> by luck is it sometimes set up correctly.  But I've searched through
>>     
> the
>   
>> task structure and mm_struct and vma_struct and haven't found
>>     
> anything.
>   
>> I could be completely wrong though.
>>
>> Any help would be greatly appreciated.
>> Matt
>>
>>
>> On Wed, 2006-09-20 at 01:40 +0000, "Ian Latter"  wrote:
>>     
>>> Hello,
>>>
>>>
>>>   Is there a patch that you can refer us to for the kcomd 
>>> segfault? (as in, the one that contains the kcomd code, 
>>> not the one that contains the fix ;-)
>>>
>>>   I'm not in a position to test it, but I can run a set of eyes
>>> over it - though I suspect I've coded more segfaults than 
>>> I've fixed.  Late night code and pointers to pointers don't
>>> mix ...
>>>
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>>       
>>>> From: "Matt Dew" <[email protected]>
>>>> To: <moshe-ay74M1d3r6RWk0Htik3J/[email protected]>
>>>> Subject:  [Openmosix-devel] komd issues - was
>>>>         
>> [Re:	[openMosix-general]	openmosix 
>>     
>>> 2.4.26 in 2.4.31?]
>>>       
>>>> Date: Tue, 19 Sep 2006 17:11:49 -0600
>>>>
>>>> Moshe,
>>>>   kcomd has one show stopper.  There is a bug that causes migrated
>>>> processes to segfault whenever a system call is issued.  Since
>>>>         
> even
>   
>>>> exit() is a system call it's a major problem.  This bug doesn't
>>>>         
>> happen
>>     
>>>> on every migrated process so it's been difficult to pin down.  
>>>>
>>>> Sadly, I've spent a large amount of time on this bug to no avail. 
>>>>         
> I
>   
>>>> need some assistance in fixing it.
>>>>
>>>> Other issues are to finish the spinlocks for smp safety and change
>>>>         
>> the
>>     
>>>> migration code to speed up migrations.  Neither of these two do I
>>>> consider major issues.
>>>>
>>>>
>>>> Florian has been very helpful in breaking up the big patch into
>>>>         
>> smaller
>>     
>>>> ones.  Thanks again Florian.
>>>>
>>>> Matt
>>>>
>>>>
>>>> On Mon, 2006-09-18 at 09:16 +0000, moshe bar  wrote:
>>>>         
>>>>> We need to have a strong effort to test your tools by as many
>>>>>           
>> people  
>>     
>>>>> as possible and then release them as one package by Kris.
>>>>>
>>>>> Matt what's missing on the kcomd side?
>>>>>
>>>>> Moshe
>>>>>
>>>>>
>>>>> On Sep 18, 2006, at 4:24 AM, Carl Radford ((DC0854-IT)) wrote:
>>>>>
>>>>>           
>>>>>> Hi Moshe,
>>>>>>
>>>>>> The 2.6 tools are not the problem (my version is already
>>>>>>             
> usable,
>   
>>  
>>     
>>>>>> awaiting user feedback).
>>>>>> Matt Dew has been putting some serious effort into kcomd, and
>>>>>>             
>> needs 
>>     
>>>>>> the help of others to put some
>>>>>> effort in. The only person that appears to be onboard with
>>>>>>             
> this
>   
>> so  
>>     
>>>>>> far is Florian.
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: moshe bar [mailto:moshe-ay74M1d3r6RWk0Htik3J/[email protected]]
>>>>>> Sent: 17 September 2006 16:25
>>>>>> To: [email protected]
>>>>>> Cc: openmosix-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org; Irfan Habib
>>>>>> Subject: Re: [openMosix-general] openmosix 2.4.26 in 2.4.31?
>>>>>>
>>>>>>
>>>>>> Martin
>>>>>>
>>>>>> Yes, we are glad to have oMFS and DFSA behind us. Using
>>>>>>             
>> something
>>     
>>>>>> like Red Hat's GFS is so much more better.
>>>>>>
>>>>>> David (Orcero), where are we with the user space tools?
>>>>>>
>>>>>> Moshe
>>>>>>
>>>>>>
>>>>>> On Sep 17, 2006, at 8:51 AM, Deadpan110 wrote:
>>>>>>
>>>>>>             
>>>>>>> I read somewhere in the oM development user lists that
>>>>>>>               
> someone
>   
>> was
>>     
>>>>>>> working on a 2.4.32 kernel patch (without checking, I wouldnt
>>>>>>>               
>> know 
>>     
>>>>>>> how
>>>>>>> stable it is or even if it is finished).
>>>>>>>
>>>>>>> openMosix could definately do with a patch for 2.4.32 while
>>>>>>>               
> we
>   
>> have
>>     
>>>>>>> the long wait for the 2.6.* versions with userspace tools.
>>>>>>>
>>>>>>> Out of curiosity, I tried the Mosix 2.4.32 kernel patch and
>>>>>>>               
>> found
>>     
>>>> it
>>>>         
>>>>>>> fairly unstable along with the old problems of MFS and DFSA
>>>>>>> (expecially if you use pivot_root).
>>>>>>>
>>>>>>> It didn't take me long to decide to switch back to openMosix
>>>>>>>               
>> 2.4.26
>>     
>>>>>>> instead!
>>>>>>>
>>>>>>> Martin
>>>>>>>
>>>>>>> On 15/09/06, James Wagner <jwagner-I/[email protected]> wrote:
>>>>>>>               
>>>>>>>> I've tried to do so, but after 3 hours of beating my head
>>>>>>>>                 
> into
>   
>> the
>>     
>>>>>>>> wall
>>>>>>>> trying to determine the differences and exactly where to
>>>>>>>>                 
>> manually
>>     
>>>>>>>> apply
>>>>>>>> the changes, gave up.  It's far easier to simply download
>>>>>>>>                 
> the
>   
>> full
>>     
>>>>>>>> (already-patched) 2.4.26 kernel and configure lilo to
>>>>>>>>                 
>> dual-boot.
>>     
>>>>>>>> I only
>>>>>>>> needed a cluster's power for a single project though, so
>>>>>>>>                 
> this
>   
>> may
>>     
>>>>>>>> not be
>>>>>>>> acceptable for your situation.
>>>>>>>>
>>>>>>>> I take it that you're another slackware fan? :)
>>>>>>>>
>>>>>>>> Jim
>>>>>>>>
>>>>>>>> Irfan Habib wrote:
>>>>>>>>
>>>>>>>>                 
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> Is it possible for me to patch the 2.4.31 kernel with
>>>>>>>>> the available OM 2.4.26 patch?
>>>>>>>>>
>>>>>>>>> regards
>>>>>>>>> Irfan
>>>>>>>>>
>>>>>>>>> __________________________________________________
>>>>>>>>> Do You Yahoo!?
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>>>>>>>>>                   
>> around
>>     
>>>>>>>>> http://mail.yahoo.com
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>                   
> ------------------------------------------------------------------- 
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>>>>>>>>> _______________________________________________
>>>>>>>>> openMosix-general mailing list
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>>>>>>>>>
>>>>>>>>>                   
>> https://lists.sourceforge.net/lists/listinfo/openmosix-general
>>     
>>>>>>>>>
>>>>>>>>>                   
>>>>>>>>                 
> --------------------------------------------------------------------
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>>>>>>>> -
>>>>>>>> ----
>>>>>>>> Using Tomcat but need to do more? Need to support web
>>>>>>>>                 
>> services,
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>>>>>>>> security?
>>>>>>>> Get stuff done quickly with pre-integrated technology to
>>>>>>>>                 
> make
>   
>> your
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>>>>>>>> job easier
>>>>>>>> Download IBM WebSphere Application Server v.1.0.1 based on
>>>>>>>>                 
>> Apache
>>     
>>>>>>>> Geronimo
>>>>>>>> http://sel.as-us.falkag.net/sel?
>>>>>>>> cmd=lnk&kid=120709&bid=263057&dat=121642
>>>>>>>> _______________________________________________
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>>>>>>>>
>>>>>>>>                 
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>   
>>>>>>>               
>> --------------------------------------------------------------------- 
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>>>>>>> -
>>>>>>> ---
>>>>>>> Using Tomcat but need to do more? Need to support web
>>>>>>>               
> services,
>   
>>>>>>> security?
>>>>>>> Get stuff done quickly with pre-integrated technology to make
>>>>>>>               
>> your
>>     
>>>>>>> job easier
>>>>>>> Download IBM WebSphere Application Server v.1.0.1 based on
>>>>>>>               
>> Apache
>>     
>>>>>>> Geronimo
>>>>>>> http://sel.as-us.falkag.net/sel?
>>>>>>> cmd=lnk&kid=120709&bid=263057&dat=121642
>>>>>>> _______________________________________________
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>>>>>>>
>>>>>>>               
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>   
>>>>>>
>>>>>>             
>> ----------------------------------------------------------------------
>>     
>
>   
>>>>>> ---
>>>>>> Using Tomcat but need to do more? Need to support web
>>>>>>             
> services, 
>   
>>>>>> security?
>>>>>> Get stuff done quickly with pre-integrated technology to make
>>>>>>             
>> your  
>>     
>>>>>> job easier
>>>>>> Download IBM WebSphere Application Server v.1.0.1 based on
>>>>>>             
>> Apache  
>>     
>>>>>> Geronimo
>>>>>> http://sel.as-us.falkag.net/sel? 
>>>>>> cmd=lnk&kid=120709&bid=263057&dat=121642
>>>>>> _______________________________________________
>>>>>> openMosix-general mailing list
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>>>>>> https://lists.sourceforge.net/lists/listinfo/openmosix-general
>>>>>>             
>>>>>
>>>>>           
> -------------------------------------------------------------------------
>   
>>>>> Using Tomcat but need to do more? Need to support web services,
>>>>>           
>>>> security?
>>>>         
>>>>> Get stuff done quickly with pre-integrated technology to make
>>>>>           
> your
>   
>> job
>>     
>>>> easier
>>>>         
>>>>> Download IBM WebSphere Application Server v.1.0.1 based on
>>>>>           
> Apache
>   
>>>> Geronimo
>>>>         
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
>   
>>>>> _______________________________________________
>>>>> openMosix-devel mailing list
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>>>>> https://lists.sourceforge.net/lists/listinfo/openmosix-devel
>>>>>           
>>>>
>>>>         
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>>>>         
>>> --
>>> Ian Latter
>>> Late night coder ..
>>> http://midnightcode.org/
>>>
>>>       
>>
>>     
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