Re: 2.6.17-rt1 - mm_struct leak

[Mark Hounschell <dmarkh@cfl.rr.com>]

Mark Hounschell wrote:
> Vernon Mauery wrote:
>> On Sunday 18 June 2006 00:06, Ingo Molnar wrote:
>>> i have released the 2.6.17-rt1 tree, which can be downloaded from the
>>> usual place:
>> I was given a test case to run that seemed to cause the machine to run the 
>> OOM-killer after a bunch of iterations.  The test was run like:
>>
>> $ for ((i=0;i<50000;i++)); do ./test; done
>>
>> and somewhere in there, the LowFree would drop very low and the test and the 
>> bash shell running it would get killed.  And then since that didn't free up 
>> much memory, the machine would become very unresponsive and would have to be 
>> rebooted.
>>
>> I don't have the source for the test myself and I am still trying to reproduce 
>> it, but from what I have gathered, there is a problem cleaning up after 
>> tasks.  I monitored the machine with slabtop while running the loop and found 
>> that the size-32, pgd, pgm, and mm_struct slabs caches were constantly 
>> growing while task_struct stayed where it should be.  At one point, there 
>> were  127 task_structs and 3530 mm_structs.
>>
>> I am still trying to figure out what is going on here, but I thought I might 
>> throw this out there to see if anyone else has seen anything like this.  And 
>> possibly pointers for how to track it down.  Right now I am trying to trace 
>> down a possible mismatch between mmget and mmput in the process exit code.  I 
>> will let you know what I find.
>>
>> --Vernon
> 
> I reported a similar if not the same problem against 2.6.16-rt23
> See this thread. Subject "possible 2.6.16-rt23 OOM problem"
> 
> http://lkml.org/lkml/2006/5/25/239
> 
> I found a way around the problem so didn't pursue it. Maybe "my way around it"
> might help in tracking it down.
> 
> Mark
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See this one instead. Its my own follow up.

http://lkml.org/lkml/2006/6/7/58

Mark