Request for review JDK-8140588 - Internal Error: gc/g1/ptrQueue.hpp:126 assert(_index == _sz) failed: invariant: queues are empty when activated

[Kim Barrett]

> On Dec 24, 2016, at 10:04 AM, Alexander Harlap <alexander.harlap at oracle.com> wrote:
> 
> Please review change for JDK-8140588 - Internal Error: gc/g1/ptrQueue.hpp:126 assert(_index == _sz) failed: invariant: queues are empty when activated
> 
> Change is located at http://cr.openjdk.java.net/~aharlap/8140588/webrev.00/
> 
> It implements Per Liden fix for rechecking value of marking in progress value inside C1 g1_pre_barrier code.
> 
> Also here is optimization described by Thomas Schatzl - do recheck only if patching involved.

I wonder whether it is worth the effort of having distinct stubs for
the two cases, or just unconditionally perform the recheck in the
existing stub.  Thomas said he found no performance issue with the
simpler version.

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Throughout, copyright dates need updating.

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cpu/aarch64/vm/c1_CodeStubs_aarch64.cpp
 373   Runtime1::StubID id = patch_code() == lir_patch_none ? Runtime1::g1_pre_barrier_slow_id : Runtime1::g1_pre_barrier_slow_with_recheck_id;

Assuming we stay with the pair of stubs, this ought to be packaged up
as a helper function.

Other occurrences:
src/cpu/arm/vm/c1_CodeStubs_arm.cpp 
src/cpu/ppc/vm/c1_CodeStubs_ppc.cpp
src/cpu/s390/vm/c1_CodeStubs_s390.cpp
src/cpu/sparc/vm/c1_CodeStubs_sparc.cpp
src/cpu/x86/vm/c1_CodeStubs_x86.cpp

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