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  1. JDK
  2. JDK-8205426

Humongous continues remembered set does not match humongous start region one after Remark

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    • Subcomponent:
      gc
    • Resolved In Build:
      b22

      Backports

        Description

        JDK-8204169 introduced some checking and changes to make sure that the humongous continues region's remembered set matches the one from their corresponding humongous starts region.

        The patch does not seem to be complete (or this is a new issue) as Kitchensink rarely crashes because of that.

        GC log log snippet:

        [...]
        [2216.224s][1529512263954ms][debug][gc,heap ] GC(524) Heap after GC invocations=525 (full 9): garbage-first heap total 7412736K, used 719586K [0x000000062dc00000, 0x0000000800000000)
        [2216.224s][1529512263954ms][debug][gc,heap ] GC(524) region size 1024K, 8 young (8192K), 8 survivors (8192K)
        [2216.224s][1529512263954ms][debug][gc,heap ] GC(524) Metaspace used 44822K, capacity 46934K, committed 47280K, reserved 1091584K
        [2216.224s][1529512263954ms][debug][gc,heap ] GC(524) class space used 4151K, capacity 4799K, committed 4864K, reserved 1048576K
        [2216.224s][1529512263954ms][info ][gc ] GC(524) Pause Young (G1 Evacuation Pause) 5038M->702M(7239M) 885.290ms
        [2216.224s][1529512263954ms][info ][gc,cpu ] GC(524) User=1.00s Sys=0.01s Real=0.89s
        [2217.132s][1529512264861ms][info ][gc,heap,exit ] Heap
        [2217.132s][1529512264861ms][info ][gc,heap,exit ] garbage-first heap total 7412736K, used 911074K [0x000000062dc00000, 0x0000000800000000)
        [2217.132s][1529512264861ms][info ][gc,heap,exit ] region size 1024K, 196 young (200704K), 8 survivors (8192K)
        [2217.132s][1529512264861ms][info ][gc,heap,exit ] Metaspace used 44885K, capacity 47035K, committed 47280K, reserved 1091584K
        [2217.132s][1529512264861ms][info ][gc,heap,exit ] class space used 4162K, capacity 4833K, committed 4864K, reserved 1048576K
        [2217.140s][1529512264870ms][info ][gc,verify,start] Verifying
        [2218.621s][1529512266350ms][error][gc,verify ] Remset states differ: Region 359 (HC) remset Untracked with starts region 358 (HS) remset Complete
        [2218.621s][1529512266351ms][error][gc,verify ] Remset states differ: Region 360 (HC) remset Untracked with starts region 358 (HS) remset Complete
        [2218.621s][1529512266351ms][error][gc,verify ] Remset states differ: Region 361 (HC) remset Untracked with starts region 358 (HS) remset Complete
        [2218.621s][1529512266351ms][error][gc,verify ] Remset states differ: Region 362 (HC) remset Untracked with starts region 358 (HS) remset
        [...]

        and the corresponding heap map:

        | 358|0x0000000644200000, 0x0000000644300000, 0x0000000644300000|100%|HS| |TAMS 0x0000000644300000, 0x0000000644200000| Complete
        | 359|0x0000000644300000, 0x0000000644400000, 0x0000000644400000|100%|HC| |TAMS 0x0000000644400000, 0x0000000644300000| Untracked
        | 360|0x0000000644400000, 0x0000000644500000, 0x0000000644500000|100%|HC| |TAMS 0x0000000644500000, 0x0000000644400000| Untracked
        | 361|0x0000000644500000, 0x0000000644600000, 0x0000000644600000|100%|HC| |TAMS 0x0000000644600000, 0x0000000644500000| Untracked
        | 362|0x0000000644600000, 0x0000000644700000, 0x0000000644700000|100%|HC| |TAMS 0x0000000644700000, 0x0000000644600000| Untracked
        | 363|0x0000000644700000, 0x0000000644800000, 0x0000000644800000|100%|HC| |TAMS 0x0000000644800000, 0x0000000644700000| Untracked
        | 364|0x0000000644800000, 0x0000000644900000, 0x0000000644900000|100%|HC| |TAMS 0x0000000644900000, 0x0000000644800000| Untracked
        | 365|0x0000000644900000, 0x0000000644a00000, 0x0000000644a00000|100%|HC| |TAMS 0x0000000644a00000, 0x0000000644900000| Untracked

        I.e. HC are untracked while HS is complete.

        This is heap verification after GC:
        [stress.process.out] [2219.067s][error][gc,verify] Heap after failed verification (kind 0):

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                Assignee:
                tschatzl Thomas Schatzl
                Reporter:
                tschatzl Thomas Schatzl
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                  Updated:
                  Resolved: