RFR: 8264543: Cross modify fence optimization for x86 [v2]

[Xubo Zhang]

On Wed, 14 Jul 2021 01:14:37 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Xubo Zhang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:
>> 
>>   8264543: Using Intel serialize instruction to replace cpuid in Cross modify fence, on supported platforms
>>   rebase with master
>
> src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp line 461:
> 
>> 459: }
>> 460: 
>> 461: bool os::supports_serialize(){
> 
> This function is unnecessary and pollutes the OS namespace with something that is not OS related. Just use VM_Version::supports_serialize() directly.

orderAccess_linux_x86.hpp is included in orderAccess.hpp, atomic.hpp, etc. VM_Version is not defined in any of the nested header files. If I add inclusion of vm_version.hpp in any of these nested head filer,  it will be messy.
Not sure about the best solution here.

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PR: https://git.openjdk.java.net/jdk/pull/3334