RFR: 8319799: Recursive lightweight locking: x86 implementation [v8]

[Axel Boldt-Christmas]

On Thu, 18 Jan 2024 20:55:56 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Axel Boldt-Christmas 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 11 additional commits since the last revision:
>> 
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - top load adjustments
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Fix type
>>  - Move inflated check in fast_locked
>>  - Move top load
>>  - 8319799: Recursive lightweight locking: x86 implementation
>>  - ... and 1 more: https://git.openjdk.org/jdk/compare/a6c71235...71c48af6
>
> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 1013:
> 
>> 1011:     // Recursive.
>> 1012:     increment(Address(tagged_monitor, OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions)));
>> 1013:   }
> 
> This is sort of like the code above in fast_lock() but it's much clearer separated here.  So I think this is good.
> 
> This function passes in thread so works for 32 bits as well?

Correct, they were merged here as the juggling of registers and the access to thread was the only difference between the implementations.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/16607#discussion_r1458685680