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

[Andrew Haley]

On 03/18/2010 09:10 AM, Andreas Kohn wrote:
> On Fri, 2010-03-12 at 09:44 +0000, Andrew Haley wrote:
>> On 03/11/2010 09:06 PM, Coleen Phillimore wrote:
>>>
>>> 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.
>>
>> That's OK, but you don't need SYS_gettid.
>> Please look at http://cr.openjdk.java.net/~aph/6929067-jdk7-webrev-4/hotspot.patch
>> I changed to "/proc/self/maps", as you requested.  I think this is better.
>>
>> The copy of my webrev to cr.openjdk.java.net failed for some reason
>> I don't understand.
> 
> With this change I seem to hit the limit on the number of open files.
> Looking through it, shouldn't get_stack_bounds() close the FILE* it
> opened?

Oh, how stupid of me!  If this were gcc I'd just push a fix
immediately as obvious/trivial, but I think we need a bug opened to
push the change.

(BTW, this happened because of a mistake translating the patch I wrote
from using the C++ library into C.  The original patch used an
fstream, whose destructor closes the file.  When I did the translation
I missed the fact that I had to close the file manually.)

Andrew.