RFR(XS): 8204652: [aix] fix thread stack allocation, too big stack sizes not recognized

[David Holmes]

Looks fine to me.

Thanks,
David

On 11/06/2018 7:47 PM, Lindenmaier, Goetz wrote:
> Hi,
> 
> Is this better?
> http://cr.openjdk.java.net/~goetz/wr18/8204652-aixHugeStacksCrash/02/
> 
> It reports now:
> bin/java -XX:CompilerThreadStackSize=80000000000000
> [1.989s][warning][os,thread] The compiler thread stack size specified is invalid: 80000000000000k
> Error occurred during initialization of VM
> java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached
> 
> Best,
>    Goetz.
> 
>> -----Original Message-----
>> From: David Holmes [mailto:david.holmes at oracle.com]
>> Sent: Montag, 11. Juni 2018 10:36
>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; Thomas Stüfe
>> <thomas.stuefe at gmail.com>
>> Cc: hotspot-runtime-dev at openjdk.java.net
>> Subject: Re: RFR(XS): 8204652: [aix] fix thread stack allocation, too big stack
>> sizes not recognized
>>
>> On 11/06/2018 6:07 PM, Lindenmaier, Goetz wrote:
>>> Hi,
>>>
>>> Yes, reporting the pthread_create is a bit misleading. But it is the same
>>> as reported on linux x86_64:
>>>
>>> bin/java -XX:CompilerThreadStackSize=8000000000000
>>> [0.271s][warning][os,thread] Failed to start thread - pthread_create failed
>> (EAGAIN) for attributes: stacksize: 8000000000000k, guardsize: 0k, detached.
>>> Error occurred during initialization of VM
>>> java.lang.OutOfMemoryError: unable to create native thread: possibly out
>> of memory or process/resource limits reached
>>
>> But on linux you _do_ call pthread_create and it did fail!
>>
>>> As we know linux is bad at implementing the pthread functionality here:
>>> It accepts setting the big value as stack size, and only when you call create
>>> you get the failure.
>>
>> Does POSIX require otherwise?
>>
>>> So it's not true that the VM starts with any other value, it also crashes on
>>> linux.  And you get the same output as on linux. So I realy don't want to
>>> start implementing any clever tracing, or even implement other stack
>>> handling (setting defaults) as on linux.  I would just like to keep it as is.
>>> Currently we get a SIGSEGV which is hard to debug on aix.
>>
>> The point is the error should be reported accurately in the logging
>> information. It's not coming from pthread_create in your AIX case so
>> don't report that it is.
>>
>> David
>>
>>> Best,
>>>     Goetz
>>>
>>>> -----Original Message-----
>>>> From: Thomas Stüfe [mailto:thomas.stuefe at gmail.com]
>>>> Sent: Montag, 11. Juni 2018 06:26
>>>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>
>>>> Cc: hotspot-runtime-dev at openjdk.java.net
>>>> Subject: Re: RFR(XS): 8204652: [aix] fix thread stack allocation, too big
>> stack
>>>> sizes not recognized
>>>>
>>>> Hi Goetz,
>>>>
>>>> On Sun, Jun 10, 2018 at 9:11 PM, Lindenmaier, Goetz
>>>> <goetz.lindenmaier at sap.com> wrote:
>>>>> Hi Thomas,
>>>>>
>>>>> The stack is started with 192k.  See the output:
>>>>>
>>>>
>>>> Ah you are right. With 64K pages this would not be enough to establish
>>>> red/yellow zones and still have breathing space left.
>>>>
>>>>> bash-4.4$ ~/oJ/vms/aix_j-1/bin/java -
>>>> XX:CompilerThreadStackSize=8000000000000
>>>>> [1.482s][warning][os,thread] The compiler thread stack size specified is
>>>> invalid: 8000000000000k
>>>>> [1.483s][warning][os,thread] Failed to start thread - pthread_create
>> failed
>>>> (22=EINVAL) for attributes: stacksize: 192k, guardsize: 4k, detached.
>>>>> Error occurred during initialization of VM
>>>>> java.lang.OutOfMemoryError: unable to create native thread: possibly
>> out
>>>> of memory or process/resource limits reached
>>>>>
>>>>> I think the output is not that bad ...
>>>>
>>>> See my mail to David: I think the output is misleading, since
>>>> pthread_create() did not even run. So, "pthread_create failed" is
>>>> wrong.
>>>>
>>>> Best Regards, Thomas
>>>>
>>>>>
>>>>> Best,
>>>>>     Goetz.
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Thomas Stüfe <thomas.stuefe at gmail.com>
>>>>>> Sent: Sunday, June 10, 2018 7:33 PM
>>>>>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>
>>>>>> Cc: hotspot-runtime-dev at openjdk.java.net
>>>>>> Subject: Re: RFR(XS): 8204652: [aix] fix thread stack allocation, too big
>>>> stack
>>>>>> sizes not recognized
>>>>>>
>>>>>> Hi Goetz,
>>>>>>
>>>>>> I see what you intent to do, but I think we need to think about error
>>>>>> handling a bit more. The pattern here (which was broken you try to fix
>>>>>> it with this patch) is that we try, sequentially:
>>>>>>
>>>>>> - pthread_attr_setstacksize()
>>>>>>
>>>>>> - if ok-so-far pthread_attr_setguardsize
>>>>>>
>>>>>> - if ok-so-far pthread_ceate
>>>>>>
>>>>>> - logging and error handling
>>>>>>
>>>>>>
>>>>>> Problem with that is that in the end, we log information about a
>>>>>> failing thread creation, printing errno as if pthread_create() failed,
>>>>>> but that errno may have come actually from one of the preceeding OS
>>>>>> calls. So the error message would be misleading.
>>>>>>
>>>>>> I think it would be better to handle errors of each system call explicitly:
>>>>>>
>>>>>> pthread_attr_setstacksize()
>>>>>> if failed
>>>>>>      - log out "pthread_attr_setsize failed" and errno
>>>>>>      - [ also: optionally decide what to do: failing thread creation?
>>>>>> retry with a default stack size? ]
>>>>>>      - return false
>>>>>>
>>>>>> pthread_attr_setguardsize()
>>>>>> if failed
>>>>>>      - log out "pthread_attr_setguardsize failed" and errno
>>>>>>      - decide what to do - ignore? assert? fail thread creation? Should
>>>>>> we even care?
>>>>>>      - return false
>>>>>>
>>>>>> and then call pthread_create with the existing error handling as follow
>> up.
>>>>>>
>>>>>> What do you think?`
>>>>>>
>>>>>> (Also, if pthread_attr_setstacksize() fails, should the thread not be
>>>>>> created with the pthread default stack size, which should be ~2MB?
>> Why
>>>>>> is that stack tiny?)
>>>>>>
>>>>>> Best Regards, Thomas
>>>>>>
>>>>>>
>>>>>> On Sun, Jun 10, 2018 at 5:33 PM, Lindenmaier, Goetz
>>>>>> <goetz.lindenmaier at sap.com> wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> This fixes a crash in thread creation with too big stack sizes
>>>>>>> http://cr.openjdk.java.net/~goetz/wr18/8204652-
>>>> aixHugeStacksCrash/01/
>>>>>>> Please review.
>>>>>>>
>>>>>>> For Java and Compiler threads the return code of
>>>>>> pthread_attr_setstacksize
>>>>>>>    is overwritten. If pthread_attr_setstacksize does not succeed, a tiny
>>>>>>>    stack size with not enough space for the yellow/red pages is
>> allocated.
>>>>>>>    VM crashes with SIGSEGV right away.
>>>>>>>
>>>>>>> Best regards,
>>>>>>>     Goetz