RFR: Allow young collection to suspend marking in old generation [v14]

[earthling-amzn]

On Mon, 1 Mar 2021 10:31:35 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> earthling-amzn has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Encode active generation and old generation marking status
>>  - Do not unset preemption request flag prematurely
>>  - Disable reference processing generational mode
>
> src/hotspot/cpu/aarch64/gc/shenandoah/c1/shenandoahBarrierSetC1_aarch64.cpp line 32:
> 
>> 30: #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
>> 31: #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
>> 32: #include "gc/shenandoah/mode/shenandoahMode.hpp"
> 
> The include is unused, isn't it?

Yes, removed.

> src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp line 64:
> 
>> 62:         __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
>> 63:       } else {
>> 64:         __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::OLD_MARKING);
> 
> In the x86 variant you preserve YOUNG_MARKING there.

Good catch, was too focused on fixing the build.

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PR: https://git.openjdk.java.net/shenandoah/pull/19