RFR(s): 8152188: Allow CMSBitMapYieldQuantum for BitMap::clear_range and clear_large_range

sangheon sangheon.kim at oracle.com
Tue Apr 5 21:15:56 UTC 2016


Thanks, Jesper for reviewing this!

Sangheon


On 04/05/2016 02:13 PM, Jesper Wilhelmsson wrote:
> Looks good!
> /Jesper
>
> Den 1/4/16 kl. 22:53, skrev sangheon:
>> Hi Jon,
>>
>> Thanks for the review.
>>
>> On 04/01/2016 01:44 PM, Jon Masamitsu wrote:
>>> http://cr.openjdk.java.net/~sangheki/8152188/webrev.00/src/share/vm/runtime/commandLineFlagConstraintsGC.cpp.udiff.html 
>>>
>>>
>>>
>>> I would expand the message so that the user understands that the
>>> size depends on the heap size.
>>>
>>> + CommandLineError::print(verbose,
>>> + "CMSBitMapYieldQuantum (" SIZE_FORMAT ") must "
>>> + "be less than or equal to bitmap size (" SIZE_FORMAT ") " whose size
>>> corresponds to the size of old generation of the Java heap\n",
>>> + value, bitmap_size);
>> I like this suggestion and applied.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~sangheki/8152188/webrev.01/
>> http://cr.openjdk.java.net/~sangheki/8152188/webrev.01_to_00
>>
>> Thanks,
>> Sangheon
>>
>>
>>>
>>>
>>> The rest looks good.
>>>
>>> Jon
>>>
>>> On 3/31/2016 4:37 PM, sangheon wrote:
>>>> Hi all,
>>>>
>>>> Could I have a couple of reviews for this change?
>>>>
>>>> CMSBitMapYieldQuantum can be changed by command-line and different 
>>>> values on
>>>> this flag result in different ranges at BitMap when we clear the 
>>>> bitmap by
>>>> BitMap::clear_large_range(). And if we can't satisfy the criteria 
>>>> for 'large'
>>>> range of '32', we will face an assert from 
>>>> BitMap::clear_large_range().
>>>> As we already have clear_range(), it would be better to call it 
>>>> instead of
>>>> firing an assert.
>>>> If we change to use 'clear_range()' will resolve the problem as 
>>>> well, but I
>>>> didn't want to change like that which would result in performance 
>>>> regression.
>>>> In addition, we need a constraint to limit its maximum not to 
>>>> exceed the mark
>>>> bitmap size.
>>>>
>>>> CR: https://bugs.openjdk.java.net/browse/JDK-8152188
>>>> Webrev: http://cr.openjdk.java.net/~sangheki/8152188/webrev.00
>>>> Testing: JPRT, runtime/commandline JTREG tests for all platforms.
>>>>
>>>> Thanks,
>>>> Sangheon
>>>>
>>>
>>



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