1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_GC_G1_G1ALLOCATOR_HPP
  26 #define SHARE_GC_G1_G1ALLOCATOR_HPP
  27 
  28 #include "gc/g1/g1AllocRegion.hpp"
  29 #include "gc/g1/g1HeapRegionAttr.hpp"
  30 #include "gc/shared/collectedHeap.hpp"
  31 #include "gc/shared/plab.hpp"
  32 
  33 class G1EvacuationInfo;
  34 class G1NUMA;
  35 
  36 // Interface to keep track of which regions G1 is currently allocating into. Provides
  37 // some accessors (e.g. allocating into them, or getting their occupancy).
  38 // Also keeps track of retained regions across GCs.
  39 class G1Allocator : public CHeapObj<mtGC> {
  40   friend class VMStructs;
  41 
  42 private:
  43   G1CollectedHeap* _g1h;
  44   G1NUMA* _numa;
  45 
  46   bool _survivor_is_full;
  47   bool _old_is_full;
  48 
  49   // The number of MutatorAllocRegions used, one per memory node.
  50   size_t _num_alloc_regions;
  51 
  52   // Alloc region used to satisfy mutator allocation requests.
  53   MutatorAllocRegion* _mutator_alloc_regions;
  54 
  55   // Alloc region used to satisfy allocation requests by the GC for
  56   // survivor objects.
  57   SurvivorGCAllocRegion* _survivor_gc_alloc_regions;
  58 
  59   // Alloc region used to satisfy allocation requests by the GC for
  60   // old objects.
  61   OldGCAllocRegion _old_gc_alloc_region;
  62 
  63   HeapRegion* _retained_old_gc_alloc_region;
  64 
  65   bool survivor_is_full() const;
  66   bool old_is_full() const;
  67 
  68   void set_survivor_full();
  69   void set_old_full();
  70 
  71   void reuse_retained_old_region(G1EvacuationInfo& evacuation_info,
  72                                  OldGCAllocRegion* old,
  73                                  HeapRegion** retained);
  74 
  75   // Accessors to the allocation regions.
  76   inline MutatorAllocRegion* mutator_alloc_region(uint node_index);
  77   inline SurvivorGCAllocRegion* survivor_gc_alloc_region(uint node_index);
  78   inline OldGCAllocRegion* old_gc_alloc_region();
  79 
  80   // Allocation attempt during GC for a survivor object / PLAB.
  81   HeapWord* survivor_attempt_allocation(size_t min_word_size,
  82                                         size_t desired_word_size,
  83                                         size_t* actual_word_size,
  84                                         uint node_index);
  85 
  86   // Allocation attempt during GC for an old object / PLAB.
  87   HeapWord* old_attempt_allocation(size_t min_word_size,
  88                                    size_t desired_word_size,
  89                                    size_t* actual_word_size);
  90 
  91   // Node index of current thread.
  92   inline uint current_node_index() const;
  93 
  94 public:
  95   G1Allocator(G1CollectedHeap* heap);
  96   ~G1Allocator();
  97 
  98   uint num_nodes() { return (uint)_num_alloc_regions; }
  99 
 100 #ifdef ASSERT
 101   // Do we currently have an active mutator region to allocate into?
 102   bool has_mutator_alloc_region();
 103 #endif
 104 
 105   void init_mutator_alloc_regions();
 106   void release_mutator_alloc_regions();
 107 
 108   void init_gc_alloc_regions(G1EvacuationInfo& evacuation_info);
 109   void release_gc_alloc_regions(G1EvacuationInfo& evacuation_info);
 110   void abandon_gc_alloc_regions();
 111   bool is_retained_old_region(HeapRegion* hr);
 112 
 113   // Allocate blocks of memory during mutator time.
 114 
 115   inline HeapWord* attempt_allocation(size_t min_word_size,
 116                                       size_t desired_word_size,
 117                                       size_t* actual_word_size);
 118   inline HeapWord* attempt_allocation_locked(size_t word_size);
 119   inline HeapWord* attempt_allocation_force(size_t word_size);
 120 
 121   size_t unsafe_max_tlab_alloc();
 122   size_t used_in_alloc_regions();
 123 
 124   // Allocate blocks of memory during garbage collection. Will ensure an
 125   // allocation region, either by picking one or expanding the
 126   // heap, and then allocate a block of the given size. The block
 127   // may not be a humongous - it must fit into a single heap region.
 128   HeapWord* par_allocate_during_gc(G1HeapRegionAttr dest,
 129                                    size_t word_size,
 130                                    uint node_index);
 131 
 132   HeapWord* par_allocate_during_gc(G1HeapRegionAttr dest,
 133                                    size_t min_word_size,
 134                                    size_t desired_word_size,
 135                                    size_t* actual_word_size,
 136                                    uint node_index);
 137 };
 138 
 139 // Manages the PLABs used during garbage collection. Interface for allocation from PLABs.
 140 // Needs to handle multiple contexts, extra alignment in any "survivor" area and some
 141 // statistics.
 142 class G1PLABAllocator : public CHeapObj<mtGC> {
 143   friend class G1ParScanThreadState;
 144 private:
 145   typedef G1HeapRegionAttr::region_type_t region_type_t;
 146 
 147   G1CollectedHeap* _g1h;
 148   G1Allocator* _allocator;
 149 
 150   PLAB** _alloc_buffers[G1HeapRegionAttr::Num];
 151 
 152   // The survivor alignment in effect in bytes.
 153   // == 0 : don't align survivors
 154   // != 0 : align survivors to that alignment
 155   // These values were chosen to favor the non-alignment case since some
 156   // architectures have a special compare against zero instructions.
 157   const uint _survivor_alignment_bytes;
 158 
 159   // Number of words allocated directly (not counting PLAB allocation).
 160   size_t _direct_allocated[G1HeapRegionAttr::Num];
 161 
 162   void flush_and_retire_stats();
 163   inline PLAB* alloc_buffer(G1HeapRegionAttr dest, uint node_index) const;
 164   inline PLAB* alloc_buffer(region_type_t dest, uint node_index) const;
 165 
 166   // Returns the number of allocation buffers for the given dest.
 167   // There is only 1 buffer for Old while Young may have multiple buffers depending on
 168   // active NUMA nodes.
 169   inline uint alloc_buffers_length(region_type_t dest) const;
 170 
 171   // Calculate the survivor space object alignment in bytes. Returns that or 0 if
 172   // there are no restrictions on survivor alignment.
 173   static uint calc_survivor_alignment_bytes();
 174 
 175   bool may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const;
 176 public:
 177   G1PLABAllocator(G1Allocator* allocator);
 178   ~G1PLABAllocator();
 179 
 180   size_t waste() const;
 181   size_t undo_waste() const;
 182 
 183   // Allocate word_sz words in dest, either directly into the regions or by
 184   // allocating a new PLAB. Returns the address of the allocated memory, NULL if
 185   // not successful. Plab_refill_failed indicates whether an attempt to refill the
 186   // PLAB failed or not.
 187   HeapWord* allocate_direct_or_new_plab(G1HeapRegionAttr dest,
 188                                         size_t word_sz,
 189                                         bool* plab_refill_failed,
 190                                         uint node_index);
 191 
 192   // Allocate word_sz words in the PLAB of dest.  Returns the address of the
 193   // allocated memory, NULL if not successful.
 194   inline HeapWord* plab_allocate(G1HeapRegionAttr dest,
 195                                  size_t word_sz,
 196                                  uint node_index);
 197 
 198   inline HeapWord* allocate(G1HeapRegionAttr dest,
 199                             size_t word_sz,
 200                             bool* refill_failed,
 201                             uint node_index);
 202 
 203   void undo_allocation(G1HeapRegionAttr dest, HeapWord* obj, size_t word_sz, uint node_index);
 204 };
 205 
 206 // G1ArchiveRegionMap is an array used to mark G1 regions as
 207 // archive regions.  This allows a quick check for whether an object
 208 // should not be marked because it is in an archive region.
 209 class G1ArchiveRegionMap : public G1BiasedMappedArray<uint8_t> {
 210 public:
 211   static const uint8_t NoArchive = 0;
 212   static const uint8_t OpenArchive = 1;
 213   static const uint8_t ClosedArchive = 2;
 214 
 215 protected:
 216   uint8_t default_value() const { return NoArchive; }
 217 };
 218 
 219 // G1ArchiveAllocator is used to allocate memory in archive
 220 // regions. Such regions are not scavenged nor compacted by GC.
 221 // There are two types of archive regions, which are
 222 // differ in the kind of references allowed for the contained objects:
 223 //
 224 // - 'Closed' archive region contain no references outside of other
 225 //   closed archive regions. The region is immutable by GC. GC does
 226 //   not mark object header in 'closed' archive region.
 227 // - An 'open' archive region allow references to any other regions,
 228 //   including closed archive, open archive and other java heap regions.
 229 //   GC can adjust pointers and mark object header in 'open' archive region.
 230 class G1ArchiveAllocator : public CHeapObj<mtGC> {
 231 protected:
 232   bool _open; // Indicate if the region is 'open' archive.
 233   G1CollectedHeap* _g1h;
 234 
 235   // The current allocation region
 236   HeapRegion* _allocation_region;
 237 
 238   // Regions allocated for the current archive range.
 239   GrowableArray<HeapRegion*> _allocated_regions;
 240 
 241   // The number of bytes used in the current range.
 242   size_t _summary_bytes_used;
 243 
 244   // Current allocation window within the current region.
 245   HeapWord* _bottom;
 246   HeapWord* _top;
 247   HeapWord* _max;
 248 
 249   // Allocate a new region for this archive allocator.
 250   // Allocation is from the top of the reserved heap downward.
 251   bool alloc_new_region();
 252 
 253 public:
 254   G1ArchiveAllocator(G1CollectedHeap* g1h, bool open) :
 255     _open(open),
 256     _g1h(g1h),
 257     _allocation_region(NULL),
 258     _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions,
 259                                                          ResourceObj::C_HEAP),
 260                         2), true /* C_Heap */),
 261     _summary_bytes_used(0),
 262     _bottom(NULL),
 263     _top(NULL),
 264     _max(NULL) { }
 265 
 266   virtual ~G1ArchiveAllocator() {
 267     assert(_allocation_region == NULL, "_allocation_region not NULL");
 268   }
 269 
 270   static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h, bool open);
 271 
 272   // Allocate memory for an individual object.
 273   HeapWord* archive_mem_allocate(size_t word_size);
 274 
 275   // Return the memory ranges used in the current archive, after
 276   // aligning to the requested alignment.
 277   void complete_archive(GrowableArray<MemRegion>* ranges,
 278                         size_t end_alignment_in_bytes);
 279 
 280   // The number of bytes allocated by this allocator.
 281   size_t used() {
 282     return _summary_bytes_used;
 283   }
 284 
 285   // Clear the count of bytes allocated in prior G1 regions. This
 286   // must be done when recalculate_use is used to reset the counter
 287   // for the generic allocator, since it counts bytes in all G1
 288   // regions, including those still associated with this allocator.
 289   void clear_used() {
 290     _summary_bytes_used = 0;
 291   }
 292 
 293   // Create the _archive_region_map which is used to identify archive objects.
 294   static inline void enable_archive_object_check();
 295 
 296   // Mark regions containing the specified address range as archive/non-archive.
 297   static inline void set_range_archive(MemRegion range, bool open);
 298   static inline void clear_range_archive(MemRegion range, bool open);
 299 
 300   // Check if the object is in closed archive
 301   static inline bool is_closed_archive_object(oop object);
 302   // Check if the object is in open archive
 303   static inline bool is_open_archive_object(oop object);
 304   // Check if the object is either in closed archive or open archive
 305   static inline bool is_archived_object(oop object);
 306 
 307 private:
 308   static bool _archive_check_enabled;
 309   static G1ArchiveRegionMap  _archive_region_map;
 310   static G1ArchiveRegionMap  _open_archive_region_map;
 311 
 312   // Check if an object is in a closed archive region using the _closed_archive_region_map.
 313   static inline bool in_closed_archive_range(oop object);
 314   // Check if an object is in open archive region using the _open_archive_region_map.
 315   static inline bool in_open_archive_range(oop object);
 316 
 317   // Check if archive object checking is enabled, to avoid calling in_open/closed_archive_range
 318   // unnecessarily.
 319   static inline bool archive_check_enabled();
 320 };
 321 
 322 #endif // SHARE_GC_G1_G1ALLOCATOR_HPP