RFC: Draft JEP: Generational ZGC

[Stefan Karlsson]

Thanks for confirming!

StefanK

On 2022-10-18 03:03, Leslie Zhai wrote:
> Hi Stefan,
>
> Works for gcc 8.3.0 :)
>
> Thanks,
>
> Leslie Zhai
>
> 在 2022/10/17 下午11:28, Stefan Karlsson 写道:
>> Hi Leslie,
>>
>> Could you test if this branch compiles as expected?
>> https://urldefense.com/v3/__https://github.com/stefank/jdk/tree/zgc_generational_found_old_initialization__;!!ACWV5N9M2RV99hQ!I-bxBQS8NkuugX0qLaeWKH6H_I5dNetw3sgNNCjhWQ5nCzjOQaJaPy-rHZeT_mvY-BpX2xJaHo2I2VGO_V4udxamQA$ 
>>
>>
>> I asked around and it seems like array initialization uses 
>> copy-initialization of the elements, and that older GCCs didn't take 
>> the opportunity to convert the copying into move operations. Or 
>> something along those lines. I've restructured the code to prevent 
>> that problem.
>>
>> Thanks for reporting,
>> StefanK
>>
>> On 2022-10-17 12:03, Leslie Zhai wrote:
>>> Hi Stefan,
>>>
>>> gcc 8.3.0 failed to work after the commit 
>>> 7d0b267e87ec6120a74e5b6282c5e395786d2546: 
>>> https://urldefense.com/v3/__https://github.com/openjdk/zgc/commit/7d0b267e87ec6120a74e5b6282c5e395786d2546__;!!ACWV5N9M2RV99hQ!I-bxBQS8NkuugX0qLaeWKH6H_I5dNetw3sgNNCjhWQ5nCzjOQaJaPy-rHZeT_mvY-BpX2xJaHo2I2VGO_V5_-nBi5A$ 
>>>
>>>
>>> Building target 'images' in configuration 
>>> 'linux-aarch64-server-fastdebug'
>>> Updating support/modules_libs/java.base/server/libjvm.so due to 1 
>>> file(s)
>>> /home/zhaixiang/zgc/src/hotspot/share/gc/z/zPageTable.cpp: In 
>>> constructor 'ZPageTable::FoundOld::FoundOld()':
>>> /home/zhaixiang/zgc/src/hotspot/share/gc/z/zPageTable.cpp:59:15: 
>>> error: use of deleted function 'CHeapBitMap::CHeapBitMap(const 
>>> CHeapBitMap&)'
>>>      _current{0} {}
>>>                ^
>>> In file included from 
>>> /home/zhaixiang/zgc/src/hotspot/share/memory/allocation.hpp:29,
>>>                  from 
>>> /home/zhaixiang/zgc/src/hotspot/share/classfile/classLoaderData.hpp:28,
>>>                  from 
>>> /home/zhaixiang/zgc/src/hotspot/share/precompiled/precompiled.hpp:34:
>>> /home/zhaixiang/zgc/src/hotspot/share/utilities/bitMap.hpp:488:15: 
>>> note: declared here
>>>    NONCOPYABLE(CHeapBitMap);
>>>                ^~~~~~~~~~~
>>> /home/zhaixiang/zgc/src/hotspot/share/utilities/globalDefinitions.hpp:84:24: 
>>> note: in definition of macro 'NONCOPYABLE'
>>>  #define NONCOPYABLE(C) C(C const&) = delete; C& operator=(C const&) 
>>> = delete /* next token must be ; */
>>>                         ^
>>> make[3]: *** [lib/CompileJvm.gmk:149: 
>>> /home/zhaixiang/zgc/build/linux-aarch64-server-fastdebug/hotspot/variant-server/libjvm/objs/zPageTable.o] 
>>> Error 1
>>> make[3]: *** Waiting for unfinished jobs....
>>> make[2]: *** [make/Main.gmk:252: hotspot-server-libs] Error 2
>>>
>>> ERROR: Build failed for target 'images' in configuration 
>>> 'linux-aarch64-server-fastdebug' (exit code 2)
>>>
>>> So I just reverted the commit then continue my porting work.
>>>
>>> How to compatible with low version GNU compiler?
>>>
>>> Thanks,
>>>
>>> Leslie Zhai
>>>
>>> 在 2022/10/17 下午5:47, Stefan Karlsson 写道:
>>>> The development of Generational ZGC happens in this project branch:
>>>> https://urldefense.com/v3/__https://github.com/openjdk/zgc/tree/zgc_generational__;!!ACWV5N9M2RV99hQ!I-bxBQS8NkuugX0qLaeWKH6H_I5dNetw3sgNNCjhWQ5nCzjOQaJaPy-rHZeT_mvY-BpX2xJaHo2I2VGO_V76pupRgw$ 
>>>>
>>>> StefanK
>>>>
>>>> On 2022-10-14 14:47, Stefan Karlsson wrote:
>>>>> Hi all,
>>>>>
>>>>> I have created a draft JEP for Generational ZGC. For details, see 
>>>>> the JBS entry:
>>>>>
>>>>> https://bugs.openjdk.org/browse/JDK-8272979
>>>>>
>>>>> Comments and feedback are welcome.
>>>>>
>>>>> Thanks,
>>>>> StefanK
>>>
>