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  1. JDK
  2. JDK-8217016

Shenandoah: Streamline generation of CAS barriers

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    • gc
    • 12
    • b06
    • x86_64
    • generic

    Backports

      Description

        Currently, we have a bit of a mess in ShenandoahBarrierSetAssembler::cmpxchg_oop(): It has special code paths for C1-only (everthing under the boolean arg 'encode') and it has a code path for !ShenandoahCASBarrier. Also, while C1 actually does not exchange, we call it with exchange==true and cmove the result. This is backwards. Also, we hacked to call storeval-barrier in C1-only path, because it can't easily be done otherwise in C1. Streamlining this code would help tremendously to clarify the actual CAS barrier algorithm, which is currently buried under all those special paths.

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            backported by

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8219669 Shenandoah: Streamline generation of CAS barriers

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            relates to

            Bug - A problem which impairs or prevents the functions of the product. JDK-8217874 Shenandoah: AArch64: Clobbered register in ShenandoahBarrierSetAssembler::cmpxchg_oop()

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8223449 Unprotected UseCompressedOops block in gc/shenandoah/shenandoahBarrierSetC1_x86.cpp

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

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                rkennke Roman Kennke
                rkennke Roman Kennke
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                  Updated:
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