--- old/src/share/vm/runtime/commandLineFlagConstraintsGC.cpp 2016-03-29 11:56:20.170007856 -0700 +++ new/src/share/vm/runtime/commandLineFlagConstraintsGC.cpp 2016-03-29 11:56:20.038007861 -0700 @@ -382,6 +382,39 @@ return Flag::SUCCESS; } +Flag::Error ParGCCardsPerStrideChunkConstraintFunc(intx value, bool verbose) { +#if INCLUDE_ALL_GCS + if (UseConcMarkSweepGC) { + // ParGCCardsPerStrideChunk shoule be compared with card table size. + size_t heap_size = Universe::heap()->reserved_region().word_size(); + CardTableModRefBS* bs = (CardTableModRefBS*)GenCollectedHeap::heap()->rem_set()->bs(); + size_t card_table_size = bs->cards_required(heap_size) - 1; // Valid card table size + + if ((size_t)value > card_table_size) { + CommandLineError::print(verbose, + "ParGCCardsPerStrideChunk (" INTX_FORMAT ") is too large for the heap size and " + "must be less than or equal to card table size (" SIZE_FORMAT ")\n", + value, card_table_size); + return Flag::VIOLATES_CONSTRAINT; + } + + // ParGCCardsPerStrideChunk is used with n_strides(ParallelGCThreads*ParGCStridesPerThread) + // from CardTableModRefBSForCTRS::process_stride(). However, ParGCStridesPerThread is already checked + // not to make an overflow with ParallelGCThreads from its constraint function. + uintx n_strides = ParallelGCThreads * ParGCStridesPerThread; + uintx ergo_max = max_uintx / n_strides; + if ((uintx)value > ergo_max) { + CommandLineError::print(verbose, + "ParGCCardsPerStrideChunk (" INTX_FORMAT ") must be " + "less than or equal to ergonomic maximum (" UINTX_FORMAT ")\n", + value, ergo_max); + return Flag::VIOLATES_CONSTRAINT; + } + } +#endif + return Flag::SUCCESS; +} + Flag::Error CMSOldPLABMinConstraintFunc(size_t value, bool verbose) { Flag::Error status = Flag::SUCCESS;