RFR: 8218743: SA: Add support for large bitmaps

Stefan Karlsson stefan.karlsson at oracle.com
Wed Feb 13 08:42:36 UTC 2019


Hi Jini,

On 2019-02-13 05:53, Jini George wrote:
> Hi Stefan,
> 
> Looks good to me. Nits: pls do change the copyright year.

Thanks for reviewing. I'll update the copyright years.

Thanks,
StefanK

> 
> Thanks,
> Jini.
> 
> On 2/11/2019 6:06 PM, Stefan Karlsson wrote:
>> Hi all,
>>
>> Please review this patch to add support for large bitmaps in the SA.
>>
>> http://cr.openjdk.java.net/~stefank/8218743/webrev.01/
>> https://bugs.openjdk.java.net/browse/JDK-8218743
>>
>> I've added a minimal interface (at, atPut, clear) that uses longs 
>> instead of ints, and changed MarkBits to use this interface.
>>
>> I've implemented a segmented bitmap that, currently, all GCs use when 
>> asked for a bitmap in MarkBits. Later ZGC will provide its own 
>> discontiguous bitmap, implementing the new interface, but that will be 
>> sent out as a separate RFE.
>>
>> I've tested this with a temporary patch that lowers the segment size 
>> and implements a jtreg test:
>> http://cr.openjdk.java.net/~stefank/8218743/webrev.test.01
>>
>> I ran through the all the tests in serviceability/sa with both these 
>> patches.
>>
>> Thanks,
>> StefanK


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