RFR: 8285487: Do not generate trampolines for runtime calls if they are not needed [v2]

[Evgeny Astigeevich]

On Wed, 27 Apr 2022 08:44:44 GMT, Boris Ulasevich <bulasevich at openjdk.org> wrote:

>> Evgeny Astigeevich has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   XX:ReservedCodeCacheSize=130M for test and update comments
>
> src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp line 406:
> 
>> 404:   // If CodeCache size > 128M, such calls must have reserved trampolines for the case:
>> 405:   // C2 compiled method calls C1 compiled method.
>> 406:   return  (entry.rspec().type() == relocInfo::runtime_call_type) ? target_needs_far_branch(entry.target())
> 
> Why is target_needs_far_branch() applied for runtime_call_type only?

Updated comment to make it clear.

> test/hotspot/jtreg/compiler/c2/aarch64/TestTrampoline.java line 57:
> 
>> 55:         // As the non-nmethod segment is put between other two segments,
>> 56:         // ReservedCodeCacheSize=240M guarantees no trampolines for runtime calls to the non-nmethod segment.
>> 57:         command.add("-XX:ReservedCodeCacheSize=240M");
> 
> To reduce memory load on the test machines, I would reduce the ReservedCodeCacheSize to 140M.
> 
> Minor stylistic comment: let us remove empty lines 59, 61, 63, 65, 67 below.

Reduced it to 130M.

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PR: https://git.openjdk.java.net/jdk/pull/8403