[8u] RFR (XS) 8257999: Parallel GC crash in gc/parallel/TestDynShrinkHeap.java: new region is not in covered_region

[Andrew Hughes]

On 19:06 Mon 01 Mar     , Aleksey Shipilev wrote:
> This is first of three patches that dance around the same issue.
> 
> Original change:
>   https://bugs.openjdk.java.net/browse/JDK-8257999
>   https://github.com/openjdk/jdk16/commit/61390d8e
> 
> Patch does not apply cleanly to 8u, because #include list is a bit different in 8u.
> 
> 8u variant:
> 
> diff -r a435c913c8ce src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp
> --- a/src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp      Thu Jun 25 08:15:07 2015 +0200
> +++ b/src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp      Mon Mar 01 19:00:24 2021 +0100
> @@ -30,10 +30,11 @@
>  #include "gc_implementation/shared/spaceDecorator.hpp"
>  #include "memory/cardTableModRefBS.hpp"
>  #include "memory/gcLocker.inline.hpp"
>  #include "oops/oop.inline.hpp"
>  #include "runtime/java.hpp"
> +#include "runtime/orderAccess.hpp"
> 
>  PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
> 
>  inline const char* PSOldGen::select_name() {
>    return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
> @@ -399,11 +400,13 @@
>    size_t new_word_size = new_memregion.word_size();
> 
>    start_array()->set_covered_region(new_memregion);
>    Universe::heap()->barrier_set()->resize_covered_region(new_memregion);
> 
> -  // ALWAYS do this last!!
> +  // Ensure the space bounds are updated and made visible to other
> +  // threads after the other data structures have been resized.
> +  OrderAccess::storestore();
>    object_space()->initialize(new_memregion,
>                               SpaceDecorator::DontClear,
>                               SpaceDecorator::DontMangle);
> 
>    assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
> 
> Testing: tier1
> 
> -- 
> Thanks,
> -Aleksey
> 

Please post patches as a link to a generated webrev.

Thanks,
-- 
Andrew :)

Senior Free Java Software Engineer
OpenJDK Package Owner
Red Hat, Inc. (http://www.redhat.com)

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