RFR: 8072070: Improve interpreter stack banging [v2]

Mon Feb 7 14:41:06 UTC 2022

On Mon, 7 Feb 2022 14:20:54 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rectify comment "(c)"
>
> src/hotspot/cpu/x86/templateInterpreterGenerator_x86.cpp line 758:
> 
>> 756:     }
>> 757: 
>> 758:     __ cmpptr(rsp, Address(thread, JavaThread::shadow_zone_safe_limit()));
> 
> stack watermark starts at stack_base, increase to current rsp to optimize away stack banging for rsp greater than this.  Cannot increase watermark if esp < shadow_zone_safe_limit because of ...

looking for a brief comment why here.

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PR: https://git.openjdk.java.net/jdk/pull/7247