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

[sangheon]

Hi Jon,

Thanks for reviewing this.

Sangheon


On 03/22/2016 10:43 AM, Jon Masamitsu wrote:
>
>
> On 3/22/2016 10:19 AM, sangheon wrote:
>> 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
>
> Looks good.
>
> Jon
>
>>
>> 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
>>>>
>>>>
>>>>
>>
>