RFR(s): 8145312: CMS: There is insufficient memory with CMSSamplingGrain=1 (original) (raw)

sangheon sangheon.kim at oracle.com
Tue Mar 8 21:40:03 UTC 2016

Hi Dmitry,

I'm okay with including the flag.

Do you mean valid additional big values will be excluded as well? I guess max_jint+1 and max_juint+1, right?

I excluded it as it will always fail with its max value and it also tries allocation which would make the testing time longer.

Thanks, Sangheon

On 03/08/2016 12:26 PM, Dmitry Dmitriev wrote:

Hi Sangheon,

Please, don't exclude testing of max range for CMSSamplingGrain flag, because in this case additional big values will be excluded too. Max value for CMSSamplingGrain will violates constraint, but it's ok for testing. Thank you, Dmitry On 08.03.2016 11:00, sangheon wrote: Hi all,

Could I have some reviews for CMSSamplingGrain flag? The flag is used to calculate points at which the young gen should be partitioned for doing parallel work, so it only makes sense to partition at a granularity equal to or larger than the object size. I am proposing to change the minimum value of CMSSamplingGrain from '1' to 'ObjectAlignmentInBytes'. (ObjectAlignmentInBytes has a range of [8, 256]). In addition, I added a constraint function to avoid an arithmetic overflow by its maximum value. CR: https://bugs.openjdk.java.net/browse/JDK-8145312 Webrev: http://cr.openjdk.java.net/~sangheki/8145312/webrev.00/ Testing: JPRT, RBT for all platforms including embedded Thanks, Sangheon

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