RFC: Draft JEP: Generational ZGC

[Leslie Zhai]

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://github.com/stefank/jdk/tree/zgc_generational_found_old_initialization 
>
>
> 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://github.com/openjdk/zgc/commit/7d0b267e87ec6120a74e5b6282c5e395786d2546 
>>
>>
>> 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://github.com/openjdk/zgc/tree/zgc_generational
>>>
>>> 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
>>