RFR: Add a limition to allocate object heap in aarch64 with tsan enabled.

[Jie He]

On Tue, 21 Apr 2020 06:19:29 GMT, Jie He <github.com+10233373+jhe33 at openjdk.org> wrote:

>> src/hotspot/share/runtime/arguments.cpp line 1863:
>> 
>>> 1862:     TSAN_ONLY(
>>> 1863: #if defined(AARCH64)
>>> 1864: #define MAX_AVAILABLE_VM_SPACE_IN_AARCH64 (1024ULL * 1024ULL * 1024ULL * 16ULL) //16GB
>> 
>> Could the code be moved to os_linux_aarch64.cpp, by overriding os::has_allocatable_memory_limit()?
>> There is "reasonable_max = limit_by_allocatable_memory(reasonable_max);" above that calls
>> os::has_allocatable_memory_limit().
>> We should avoid adding architecture-specific code in arguments.cpp if possible.
>
> yes, I think it's possible, however it will touch X86 code that moving has_allocatable_memory_limit() to
> os_linux_x86.cpp as well.

I will move it and test x86. thank you for reminding.

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PR: https://git.openjdk.java.net/tsan/pull/6