Request for approval: 6929067: Stack guard pages should be removed when thread is detached

[Coleen Phillimore]

I've added the test to the changeset and a script to run in our harness.

Also in os_linux.cpp, I changed the SYS_gettid call to go through our 
os::Linux::gettid() because on at least one linux, syscall() returns a 
long int which gets a compilation warning with %d.

open webrev at http://cr.openjdk.java.net/~coleenp/6929067/
bug link at http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6929067

Andrew, please have a look since you're the contributor.

Thanks,
Coleen

Coleen Phillimore wrote:
>
> Yes, definitely send the test case too.
>
> thanks,
> Coleen
>
> Andrew Haley wrote:
>> On 03/05/2010 05:25 PM, Coleen Phillimore wrote:
>>  
>>> This looks good to me, there are a couple of questions.  Can you use
>>> /proc/self/maps instead of getting the tid?
>>>     
>>
>> Sure.  I was being defensive because the manpage says:
>>
>> /proc/self
>>
>>     This directory refers to the process accessing the /proc
>>     filesystem, and is identical to the /proc directory named by the
>>     process ID of the same process.
>>
>> which I thought meant the PID rather than the TID.  However, the page
>> is misleading: I just checked and /proc/self refers to the TID.  (Not
>> that it really matters, as the mappings will mostly be the same
>> anyway.)
>>
>>  
>>> Also there's a 'my' instead of 'by' in the comments.
>>>     
>>
>> Fixed.
>>
>> http://cr.openjdk.java.net/~aph/6929067-jdk7-webrev-3
>>
>> By the way, I have a good regression test for this.  Should I submit
>> that too?
>>
>> Andrew.
>>   
>