RFR: 8282322: AArch64: Provide a means to eliminate all STREX family of instructions [v4]

[Dmitry Chuyko]

On Thu, 9 Jun 2022 08:56:22 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> Dmitry Chuyko has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:
>> 
>>  - Removed unnecessary changes (forced UseLSE, blank lines)
>>  - Merge branch 'openjdk:master' into JDK-8282322
>>  - Merge branch 'openjdk:master' into JDK-8282322
>>  - Use LSE in linux-aarch64 asm code if __ARM_FEATURE_ATOMICS is on
>>  - Revert "hardlse feature"
>>    
>>    This reverts commit c5da85d3282bb995f69639f8f592cc94560916c5.
>>  - Merge branch 'openjdk:master' into JDK-8282322
>>  - hardlse feature
>
> src/hotspot/os_cpu/linux_aarch64/atomic_linux_aarch64.S line 266:
> 
>> 264: aarch64_atomic_cmpxchg_4_relaxed_default_impl:
>> 265: #ifdef __ARM_FEATURE_ATOMICS
>> 266:         prfm    pstl1strm, [x0]
> 
> This still looks wrong. You do want PRFM before LDXR, surely. Not before CAS.

Thanks, fixed both points to be similar to others.

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PR: https://git.openjdk.org/jdk/pull/8779