JDK-6689523 : max heap calculation for compressed oops is off by MaxPermSize
  • Type: Bug
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: hs13
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2008-04-16
  • Updated: 2011-02-15
  • Resolved: 2011-02-15
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JDK 6 JDK 7 Other
6u14Fixed 7Fixed hs13Fixed
Description
The max size for UseCompressedOops didn't realize that perm gen isn't included in MaxHeapSize, so needs to be fixed.
Comments
EVALUATION 6689523: max heap calculation for compressed oops is off by MaxPermSize Summary: Need to subtract MaxPermSize from the total heap size when determining whether compressed oops is turned on. Reviewed-by: jmasa, jcoomes, kvn
30-04-2008
SUGGESTED FIX src/share/vm/runtime/arguments.cpp Print this page *** 1123,1132 **** --- 1123,1140 ---- "for the CMS collector. CMSParPromoteBlocksToClaim will take precedence.\n"); } } } + unsigned long max_heap_for_compressed_oops() { + #ifdef _LP64 + return 32*G - MaxPermSize - os::vm_page_size(); + #else + return DefaultMaxRAM; + #endif // _LP64 + } + bool Arguments::should_auto_select_low_pause_collector() { if (UseAutoGCSelectPolicy && !FLAG_IS_DEFAULT(MaxGCPauseMillis) && (MaxGCPauseMillis <= AutoGCSelectPauseMillis)) { if (PrintGCDetails) { *** 1167,1177 **** #ifdef _LP64 // Compressed Headers do not work with CMS, which uses a bit in the klass // field offset to determine free list chunk markers. // Check that UseCompressedOops can be set with the max heap size allocated // by ergonomics. ! if (!UseConcMarkSweepGC && MaxHeapSize <= (32*G - os::vm_page_size())) { if (FLAG_IS_DEFAULT(UseCompressedOops)) { FLAG_SET_ERGO(bool, UseCompressedOops, true); } } else { if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) { --- 1175,1185 ---- #ifdef _LP64 // Compressed Headers do not work with CMS, which uses a bit in the klass // field offset to determine free list chunk markers. // Check that UseCompressedOops can be set with the max heap size allocated // by ergonomics. ! if (!UseConcMarkSweepGC && MaxHeapSize <= max_heap_for_compressed_oops()) { if (FLAG_IS_DEFAULT(UseCompressedOops)) { FLAG_SET_ERGO(bool, UseCompressedOops, true); } } else { if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) { *** 1203,1213 **** Abstract_VM_Version::parallel_worker_threads()); if (FLAG_IS_DEFAULT(MaxHeapSize)) { const uint64_t reasonable_fraction = os::physical_memory() / DefaultMaxRAMFraction; ! const uint64_t maximum_size = (uint64_t) DefaultMaxRAM; size_t reasonable_max = (size_t) os::allocatable_physical_memory(reasonable_fraction); if (reasonable_max > maximum_size) { reasonable_max = maximum_size; } --- 1211,1224 ---- Abstract_VM_Version::parallel_worker_threads()); if (FLAG_IS_DEFAULT(MaxHeapSize)) { const uint64_t reasonable_fraction = os::physical_memory() / DefaultMaxRAMFraction; ! const uint64_t maximum_size = (uint64_t) ! (FLAG_IS_DEFAULT(DefaultMaxRAM) ? ! MIN2(max_heap_for_compressed_oops(), DefaultMaxRAM) : ! DefaultMaxRAM); size_t reasonable_max = (size_t) os::allocatable_physical_memory(reasonable_fraction); if (reasonable_max > maximum_size) { reasonable_max = maximum_size;
16-04-2008