Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp @ 20543:e7d0505c8a30
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 | 1f1d373cd044 |
| children | 7848fc12602b |
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--- a/src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp Fri Oct 10 15:45:45 2014 +0200 +++ b/src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp Fri Oct 10 15:51:58 2014 +0200 @@ -124,7 +124,8 @@ } #endif -void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions) { +void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) { + // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter. MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords); _card_table->clear(mr); }