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  1. JDK
  2. JDK-8297487

G1 Remark: no need to keep alive oop constants of nmethods on stack

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    • Enhancement
    • Resolution: Fixed
    • P4
    • 21
    • 20
    • hotspot
    • gc
    • b05
    • Fix failed

    Description

      The stackwalks to keep alive oops of nmethods found on stack during G1 remark seem redundant as nmethod entry barriers do the job already: https://github.com/openjdk/jdk/blob/f26bd4e0e8b68de297a9ff93526cd7fac8668320/src/hotspot/share/gc/shared/barrierSetNMethod.cpp#L85

      Objects in the constant pool of a nmethod are weakly referenced. So G1 requires nmethod entry barriers to conservatively keep alive the constant objects for SATB during concurrent marking (see https://bugs.openjdk.org/browse/JDK-8288970).

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          is blocked by

          Enhancement - null JDK-8291302 ARM32: nmethod entry barriers support

          • P3 - Major loss of function.
          • Resolved
          is cloned by

          Enhancement - null JDK-8302462 [REDO] 8297487: G1 Remark: no need to keep alive oop constants of nmethods on stack

          • 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-8288970 G1 does not keep weak nmethod oops alive

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8299956 [BACKOUT] 8297487: G1 Remark: no need to keep alive oop constants of nmethods on stack

          • P1 - Blocks development and/or testing work, production could not run.
          • Closed

          Enhancement - null JDK-8290025 Remove the Sweeper

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

          Commit Commit openjdk/jdk/eab1e626

          Review Review openjdk/jdk/11314

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              rrich Richard Reingruber
              rrich Richard Reingruber
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                Created:
                Updated:
                Resolved: