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comparison src/share/vm/gc_implementation/g1/concurrentMark.cpp @ 20543:e7d0505c8a30

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8059758: Footprint regressions with JDK-8038423 Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything. Reviewed-by: jwilhelm, brutisso
author tschatzl
date Fri, 10 Oct 2014 15:51:58 +0200
parents c02ec279b062
children b12a2a9b05ca
comparison
equal deleted inserted replaced
20542:0fcaab91d485 20543:e7d0505c8a30
128 _bm.set_size(_bmWordSize >> _shifter); 128 _bm.set_size(_bmWordSize >> _shifter);
129 129
130 storage->set_mapping_changed_listener(&_listener); 130 storage->set_mapping_changed_listener(&_listener);
131 } 131 }
132 132
133 void CMBitMapMappingChangedListener::on_commit(uint start_region, size_t num_regions) { 133 void CMBitMapMappingChangedListener::on_commit(uint start_region, size_t num_regions, bool zero_filled) {
134 if (zero_filled) {
135 return;
136 }
134 // We need to clear the bitmap on commit, removing any existing information. 137 // We need to clear the bitmap on commit, removing any existing information.
135 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_region), num_regions * HeapRegion::GrainWords); 138 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_region), num_regions * HeapRegion::GrainWords);
136 _bm->clearRange(mr); 139 _bm->clearRange(mr);
137 } 140 }
138 141