RFR: 8064814: Print more helpful error message when getting OOM due to low Java Heap base when running with CompressedOops

[Thomas Stüfe]

Hi all,

a better way to fix this may be to prevent heap allocation from happening
too close to the data segment.

On Aix we regularly ran into this problem, so we added a workaround to
never attach the java heap (nor any other memory) within a safety zone
behind the data segment. The size of this safety zone is configurable via
MaxExpectedDataSegmentSize (AIX specific switch).

For details see os_aix.cpp, function "is_close_to_brk()" and its usage in
the context of reserve_memory() and friends. Maybe this feature could be
ported to other Unices - all variants where the C heap is living in the
process data segment and increased using sbrk.

Kind Regards, Thomas

On Fri, May 27, 2016 at 12:14 AM, David Holmes <david.holmes at oracle.com>
wrote:

> Hi Poonam,
>
> The changes seem okay to me - I think Coleen would need to confirm the
> accuracy of the actual words used.
>
> Note that this enhancement requires approval before it can be pushed.
>
> Thanks,
> David
>
>
> On 27/05/2016 7:39 AM, Poonam Bajaj Parhar wrote:
>
>> Hello,
>>
>> Gentle reminder!
>>
>> Thanks,
>> Poonam
>>
>> On 5/10/2016 1:04 PM, Poonam Bajaj Parhar wrote:
>>
>>> Hello,
>>>
>>> Could I get reviews for this small change, please!
>>> http://cr.openjdk.java.net/~poonam/8064814/webrev.00/
>>>
>>> Thanks,
>>> Poonam
>>>
>>> On 5/5/2016 6:49 AM, poonam.bajaj at oracle.com wrote:
>>>
>>>> Hello,
>>>>
>>>> Please review this simple fix for:
>>>> Bug 8064814 <https://bugs.openjdk.java.net/browse/JDK-8064814> : Print
>>>> more helpful error message when getting OOM due to low Java Heap base
>>>> when running with CompressedOops
>>>> Webrev: http://cr.openjdk.java.net/~poonam/8064814/webrev.00/
>>>>
>>>> Problem: We can encounter out-of-native-heap errors when the Java heap
>>>> is either placed in the first 4gb or 32gb address space when running
>>>> with the CompressedOops. The Java Heap base in these cases limits and
>>>> blocks the growth of the native heap.
>>>>
>>>> Fix: Print better error message giving an indication that the
>>>> out-of-native heap error may be due to the use of CompressedOops and how
>>>> it can be resolved. These changes also check if the process is running
>>>> in 32-bit mode and then print the appropriate 32-bit or 64-bit related
>>>> suggestions.
>>>>
>>>> Testing: Manual testing
>>>>
>>>> Thanks,
>>>> Poonam
>>>>
>>>>
>>>
>>