1991 
1992   G1Log::init();
1993 
1994   // Necessary to satisfy locking discipline assertions.
1995 
1996   MutexLocker x(Heap_lock);
1997 
1998   // We have to initialize the printer before committing the heap, as
1999   // it will be used then.
2000   _hr_printer.set_active(G1PrintHeapRegions);
2001 
2002   // While there are no constraints in the GC code that HeapWordSize
2003   // be any particular value, there are multiple other areas in the
2004   // system which believe this to be true (e.g. oop->object_size in some
2005   // cases incorrectly returns the size in wordSize units rather than
2006   // HeapWordSize).
2007   guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
2008 
2009   size_t init_byte_size = collector_policy()->initial_heap_byte_size();
2010   size_t max_byte_size = collector_policy()->max_heap_byte_size();
2011   size_t heap_alignment = collector_policy()->max_alignment();
2012 
2013   // Ensure that the sizes are properly aligned.
2014   Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
2015   Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
2016   Universe::check_alignment(max_byte_size, heap_alignment, "g1 heap");
2017 
2018   _cg1r = new ConcurrentG1Refine(this);
2019 
2020   // Reserve the maximum.
2021 
2022   // When compressed oops are enabled, the preferred heap base
2023   // is calculated by subtracting the requested size from the
2024   // 32Gb boundary and using the result as the base address for
2025   // heap reservation. If the requested size is not aligned to
2026   // HeapRegion::GrainBytes (i.e. the alignment that is passed
2027   // into the ReservedHeapSpace constructor) then the actual
2028   // base of the reserved heap may end up differing from the
2029   // address that was requested (i.e. the preferred heap base).
2030   // If this happens then we could end up using a non-optimal
2031   // compressed oops mode.

2169   HeapRegion* dummy_region = new_heap_region(0 /* index of bottom region */,
2170                                              _g1_reserved.start());
2171   // We'll re-use the same region whether the alloc region will
2172   // require BOT updates or not and, if it doesn't, then a non-young
2173   // region will complain that it cannot support allocations without
2174   // BOT updates. So we'll tag the dummy region as young to avoid that.
2175   dummy_region->set_young();
2176   // Make sure it's full.
2177   dummy_region->set_top(dummy_region->end());
2178   G1AllocRegion::setup(this, dummy_region);
2179 
2180   init_mutator_alloc_region();
2181 
2182   // Do create of the monitoring and management support so that
2183   // values in the heap have been properly initialized.
2184   _g1mm = new G1MonitoringSupport(this);
2185 
2186   return JNI_OK;
2187 }
2188 




2189 void G1CollectedHeap::ref_processing_init() {
2190   // Reference processing in G1 currently works as follows:
2191   //
2192   // * There are two reference processor instances. One is
2193   //   used to record and process discovered references
2194   //   during concurrent marking; the other is used to
2195   //   record and process references during STW pauses
2196   //   (both full and incremental).
2197   // * Both ref processors need to 'span' the entire heap as
2198   //   the regions in the collection set may be dotted around.
2199   //
2200   // * For the concurrent marking ref processor:
2201   //   * Reference discovery is enabled at initial marking.
2202   //   * Reference discovery is disabled and the discovered
2203   //     references processed etc during remarking.
2204   //   * Reference discovery is MT (see below).
2205   //   * Reference discovery requires a barrier (see below).
2206   //   * Reference processing may or may not be MT
2207   //     (depending on the value of ParallelRefProcEnabled
2208   //     and ParallelGCThreads).

1991 
1992   G1Log::init();
1993 
1994   // Necessary to satisfy locking discipline assertions.
1995 
1996   MutexLocker x(Heap_lock);
1997 
1998   // We have to initialize the printer before committing the heap, as
1999   // it will be used then.
2000   _hr_printer.set_active(G1PrintHeapRegions);
2001 
2002   // While there are no constraints in the GC code that HeapWordSize
2003   // be any particular value, there are multiple other areas in the
2004   // system which believe this to be true (e.g. oop->object_size in some
2005   // cases incorrectly returns the size in wordSize units rather than
2006   // HeapWordSize).
2007   guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
2008 
2009   size_t init_byte_size = collector_policy()->initial_heap_byte_size();
2010   size_t max_byte_size = collector_policy()->max_heap_byte_size();
2011   size_t heap_alignment = collector_policy()->heap_alignment();
2012 
2013   // Ensure that the sizes are properly aligned.
2014   Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
2015   Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
2016   Universe::check_alignment(max_byte_size, heap_alignment, "g1 heap");
2017 
2018   _cg1r = new ConcurrentG1Refine(this);
2019 
2020   // Reserve the maximum.
2021 
2022   // When compressed oops are enabled, the preferred heap base
2023   // is calculated by subtracting the requested size from the
2024   // 32Gb boundary and using the result as the base address for
2025   // heap reservation. If the requested size is not aligned to
2026   // HeapRegion::GrainBytes (i.e. the alignment that is passed
2027   // into the ReservedHeapSpace constructor) then the actual
2028   // base of the reserved heap may end up differing from the
2029   // address that was requested (i.e. the preferred heap base).
2030   // If this happens then we could end up using a non-optimal
2031   // compressed oops mode.

2169   HeapRegion* dummy_region = new_heap_region(0 /* index of bottom region */,
2170                                              _g1_reserved.start());
2171   // We'll re-use the same region whether the alloc region will
2172   // require BOT updates or not and, if it doesn't, then a non-young
2173   // region will complain that it cannot support allocations without
2174   // BOT updates. So we'll tag the dummy region as young to avoid that.
2175   dummy_region->set_young();
2176   // Make sure it's full.
2177   dummy_region->set_top(dummy_region->end());
2178   G1AllocRegion::setup(this, dummy_region);
2179 
2180   init_mutator_alloc_region();
2181 
2182   // Do create of the monitoring and management support so that
2183   // values in the heap have been properly initialized.
2184   _g1mm = new G1MonitoringSupport(this);
2185 
2186   return JNI_OK;
2187 }
2188 
2189 size_t G1CollectedHeap::conservative_max_heap_alignment() {
2190   return HeapRegion::max_region_size();
2191 }
2192 
2193 void G1CollectedHeap::ref_processing_init() {
2194   // Reference processing in G1 currently works as follows:
2195   //
2196   // * There are two reference processor instances. One is
2197   //   used to record and process discovered references
2198   //   during concurrent marking; the other is used to
2199   //   record and process references during STW pauses
2200   //   (both full and incremental).
2201   // * Both ref processors need to 'span' the entire heap as
2202   //   the regions in the collection set may be dotted around.
2203   //
2204   // * For the concurrent marking ref processor:
2205   //   * Reference discovery is enabled at initial marking.
2206   //   * Reference discovery is disabled and the discovered
2207   //     references processed etc during remarking.
2208   //   * Reference discovery is MT (see below).
2209   //   * Reference discovery requires a barrier (see below).
2210   //   * Reference processing may or may not be MT
2211   //     (depending on the value of ParallelRefProcEnabled
2212   //     and ParallelGCThreads).