Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp @ 1886:72a161e62cc4
6991377: G1: race between concurrent refinement and humongous object allocation
Summary: There is a race between the concurrent refinement threads and the humongous object allocation that can cause the concurrent refinement threads to corrupt the part of the BOT that it is being initialized by the humongous object allocation operation. The solution is to do the humongous object allocation in careful steps to ensure that the concurrent refinement threads always have a consistent view over the BOT, region contents, and top. The fix includes some very minor tidying up in sparsePRT.
Reviewed-by: jcoomes, johnc, ysr
| author | tonyp |
|---|---|
| date | Sat, 16 Oct 2010 17:12:19 -0400 |
| parents | c18cbe5936b8 |
| children | f95d63e2154a |
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--- a/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp Mon Oct 18 15:01:41 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp Sat Oct 16 17:12:19 2010 -0400 @@ -175,7 +175,7 @@ } assert(start_card > _array->index_for(_bottom), "Cannot be first card"); assert(_array->offset_array(start_card-1) <= N_words, - "Offset card has an unexpected value"); + "Offset card has an unexpected value"); size_t start_card_for_region = start_card; u_char offset = max_jubyte; for (int i = 0; i < BlockOffsetArray::N_powers; i++) { @@ -577,6 +577,16 @@ #endif } +void +G1BlockOffsetArray::set_for_starts_humongous(HeapWord* new_end) { + assert(_end == new_end, "_end should have already been updated"); + + // The first BOT entry should have offset 0. + _array->set_offset_array(_array->index_for(_bottom), 0); + // The rest should point to the first one. + set_remainder_to_point_to_start(_bottom + N_words, new_end); +} + ////////////////////////////////////////////////////////////////////// // G1BlockOffsetArrayContigSpace ////////////////////////////////////////////////////////////////////// @@ -626,3 +636,12 @@ "Precondition of call"); _array->set_offset_array(bottom_index, 0); } + +void +G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* new_end) { + G1BlockOffsetArray::set_for_starts_humongous(new_end); + + // Make sure _next_offset_threshold and _next_offset_index point to new_end. + _next_offset_threshold = new_end; + _next_offset_index = _array->index_for(new_end); +}