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  1. JDK
  2. JDK-8211150

G1 Full GC not purging code root memory and hence causing memory leak

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    • gc
    • b14

        G1 Full GC does not purge code root memory, and that causes a memory leak. The leak is illustrated in the attached file after_8141421_fix.png.

        I made the following simple change that purges the code root memory
        in the Full GC control path. With this change this leak goes away. (see attached file after_purge_fix.png)
        --- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
        +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
        @@ -1423,6 +1423,7 @@
                 hot_card_cache->reset_card_counts();
                 hot_card_cache->reset_hot_cache();
               }
        + purge_code_root_memory();
          
               // Rebuild remembered sets of all regions.
               if (G1CollectedHeap::use_parallel_gc_threads()) {

        We currently purge code root memory in VM_G1IncCollectionPause operation but not in VM_G1CollectFull which is causing this leak.

          1. after_8141421_fix.png
            after_8141421_fix.png
            165 kB
          2. after_purge_fix.png
            after_purge_fix.png
            106 kB

              poonam Poonam Bajaj Parhar
              poonam Poonam Bajaj Parhar
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                Created:
                Updated:
                Resolved: