RFR(s): 8152160: SIGFPE in CompactibleFreeListSpaceLAB::compute_desired_plab_size

sangheon sangheon.kim at oracle.com
Tue Mar 22 17:19:54 UTC 2016


Hi Per,

Thank you for reviewing this issue.

On 03/22/2016 08:59 AM, Per Liden wrote:
> Hi Sangheon,
>
> On 2016-03-22 03:12, sangheon wrote:
>> Hi all,
>>
>> Could I have a couple of reviews for this change?
>>
>> With large value of CMSOldPLABNumRefills, SIGFPE would happen at
>> CompactibleFreeListSpaceLAB::compute_desired_plab_size() because related
>> routine would be zero by an overflow.
>>
>> Type-casting to 'double' before the problematic division will resolve
>> the problem.
>
> Casting to double doesn't quite seem like the right thing to do here. 
> Can't this be rephrased to avoid the overflow completely, something like:
>
> _global_num_blocks[i] / _global_num_workers[i] / CMSOldPLABNumRefills
You are right!
I like this much more.

Webrev: http://cr.openjdk.java.net/~sangheki/8152160/webrev.01

Sangheon

>
> cheers,
> Per
>
>>
>> CR: https://bugs.openjdk.java.net/browse/JDK-8152160
>> Webrev: http://cr.openjdk.java.net/~sangheki/8152160/webrev.00
>> Testing: JPRT, TestOptionsWithRanges.java via RBT and manual test as CR
>> description.
>>
>> Thanks,
>> Sangheon
>>
>>
>>



More information about the hotspot-gc-dev mailing list