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comparison src/share/vm/memory/universe.hpp @ 642:660978a2a31a

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6791178: Specialize for zero as the compressed oop vm heap base Summary: Use zero based compressed oops if java heap is below 32gb and unscaled compressed oops if java heap is below 4gb. Reviewed-by: never, twisti, jcoomes, coleenp
author kvn
date Thu, 12 Mar 2009 10:37:46 -0700
parents d593294016c3
children bd441136a5ce
comparison
equal deleted inserted replaced
641:6af0a709d52b 642:660978a2a31a
88 88
89 public: 89 public:
90 methodOop get_methodOop(); 90 methodOop get_methodOop();
91 }; 91 };
92 92
93 // For UseCompressedOops.
94 struct NarrowOopStruct {
95 // Base address for oop-within-java-object materialization.
96 // NULL if using wide oops or zero based narrow oops.
97 address _base;
98 // Number of shift bits for encoding/decoding narrow oops.
99 // 0 if using wide oops or zero based unscaled narrow oops,
100 // LogMinObjAlignmentInBytes otherwise.
101 int _shift;
102 // Generate code with implicit null checks for narrow oops.
103 bool _use_implicit_null_checks;
104 };
105
93 106
94 class Universe: AllStatic { 107 class Universe: AllStatic {
95 // Ugh. Universe is much too friendly. 108 // Ugh. Universe is much too friendly.
96 friend class MarkSweep; 109 friend class MarkSweep;
97 friend class oopDesc; 110 friend class oopDesc;
179 192
180 static oop _emptySymbol; // Canonical empty string ("") symbol 193 static oop _emptySymbol; // Canonical empty string ("") symbol
181 194
182 // The particular choice of collected heap. 195 // The particular choice of collected heap.
183 static CollectedHeap* _collectedHeap; 196 static CollectedHeap* _collectedHeap;
184 // Base address for oop-within-java-object materialization. 197
185 // NULL if using wide oops. Doubles as heap oop null value. 198 // For UseCompressedOops.
186 static address _heap_base; 199 static struct NarrowOopStruct _narrow_oop;
187 200
188 // array of dummy objects used with +FullGCAlot 201 // array of dummy objects used with +FullGCAlot
189 debug_only(static objArrayOop _fullgc_alot_dummy_array;) 202 debug_only(static objArrayOop _fullgc_alot_dummy_array;)
190 // index of next entry to clear 203 // index of next entry to clear
191 debug_only(static int _fullgc_alot_dummy_next;) 204 debug_only(static int _fullgc_alot_dummy_next;)
326 339
327 // The particular choice of collected heap. 340 // The particular choice of collected heap.
328 static CollectedHeap* heap() { return _collectedHeap; } 341 static CollectedHeap* heap() { return _collectedHeap; }
329 342
330 // For UseCompressedOops 343 // For UseCompressedOops
331 static address heap_base() { return _heap_base; } 344 static address* narrow_oop_base_addr() { return &_narrow_oop._base; }
332 static address* heap_base_addr() { return &_heap_base; } 345 static address narrow_oop_base() { return _narrow_oop._base; }
346 static int narrow_oop_shift() { return _narrow_oop._shift; }
347 static void set_narrow_oop_base(address base) { _narrow_oop._base = base; }
348 static void set_narrow_oop_shift(int shift) { _narrow_oop._shift = shift; }
349 static bool narrow_oop_use_implicit_null_checks() { return _narrow_oop._use_implicit_null_checks; }
350 static void set_narrow_oop_use_implicit_null_checks(bool use) { _narrow_oop._use_implicit_null_checks = use; }
351 // Narrow Oop encoding mode:
352 // 0 - Use 32-bits oops without encoding when
353 // NarrowOopHeapBaseMin + heap_size < 4Gb
354 // 1 - Use zero based compressed oops with encoding when
355 // NarrowOopHeapBaseMin + heap_size < 32Gb
356 // 2 - Use compressed oops with heap base + encoding.
357 enum NARROW_OOP_MODE {
358 UnscaledNarrowOop = 0,
359 ZeroBasedNarrowOop = 1,
360 HeapBasedNarrowOop = 2
361 };
362 static char* preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode);
333 363
334 // Historic gc information 364 // Historic gc information
335 static size_t get_heap_capacity_at_last_gc() { return _heap_capacity_at_last_gc; } 365 static size_t get_heap_capacity_at_last_gc() { return _heap_capacity_at_last_gc; }
336 static size_t get_heap_free_at_last_gc() { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; } 366 static size_t get_heap_free_at_last_gc() { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; }
337 static size_t get_heap_used_at_last_gc() { return _heap_used_at_last_gc; } 367 static size_t get_heap_used_at_last_gc() { return _heap_used_at_last_gc; }