1 /* 2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 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). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_MUTABLESPACE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_MUTABLESPACE_HPP 27 28 #include "gc_implementation/shared/immutableSpace.hpp" 29 #include "memory/memRegion.hpp" 30 #include "utilities/copy.hpp" 31 32 // A MutableSpace is a subtype of ImmutableSpace that supports the 33 // concept of allocation. This includes the concepts that a space may 34 // be only partially full, and the querry methods that go with such 35 // an assumption. MutableSpace is also responsible for minimizing the 36 // page allocation time by having the memory pretouched (with 37 // AlwaysPretouch) and for optimizing page placement on NUMA systems 38 // by make the underlying region interleaved (with UseNUMA). 39 // 40 // Invariant: (ImmutableSpace +) bottom() <= top() <= end() 41 // top() is inclusive and end() is exclusive. 42 43 class MutableSpaceMangler; 44 45 class MutableSpace: public ImmutableSpace { 46 friend class VMStructs; 47 48 // Helper for mangling unused space in debug builds 49 MutableSpaceMangler* _mangler; 50 // The last region which page had been setup to be interleaved. 51 MemRegion _last_setup_region; 52 size_t _alignment; 53 protected: 54 HeapWord* _top; 55 56 MutableSpaceMangler* mangler() { return _mangler; } 57 58 void numa_setup_pages(MemRegion mr, bool clear_space); 59 void pretouch_pages(MemRegion mr); 60 61 void set_last_setup_region(MemRegion mr) { _last_setup_region = mr; } 62 MemRegion last_setup_region() const { return _last_setup_region; } 63 64 public: 65 virtual ~MutableSpace(); 66 MutableSpace(size_t page_size); 67 68 // Accessors 69 HeapWord* top() const { return _top; } 70 virtual void set_top(HeapWord* value) { _top = value; } 71 72 HeapWord** top_addr() { return &_top; } 73 HeapWord** end_addr() { return &_end; } 74 75 virtual void set_bottom(HeapWord* value) { _bottom = value; } 76 virtual void set_end(HeapWord* value) { _end = value; } 77 78 size_t alignment() { return _alignment; } 79 80 // Returns a subregion containing all objects in this space. 81 MemRegion used_region() { return MemRegion(bottom(), top()); } 82 83 static const bool SetupPages = true; 84 static const bool DontSetupPages = false; 85 86 // Initialization 87 virtual void initialize(MemRegion mr, 88 bool clear_space, 89 bool mangle_space, 90 bool setup_pages = SetupPages); 91 92 virtual void clear(bool mangle_space); 93 // Does the usual initialization but optionally resets top to bottom. 94 #if 0 // MANGLE_SPACE 95 void initialize(MemRegion mr, bool clear_space, bool reset_top); 96 #endif 97 virtual void update() { } 98 virtual void accumulate_statistics() { } 99 100 // Methods used in mangling. See descriptions under SpaceMangler. 101 virtual void mangle_unused_area() PRODUCT_RETURN; 102 virtual void mangle_unused_area_complete() PRODUCT_RETURN; 103 virtual void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; 104 virtual void check_mangled_unused_area_complete() PRODUCT_RETURN; 105 virtual void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; 106 107 // Used to save the space's current top for later use during mangling. 108 virtual void set_top_for_allocations() PRODUCT_RETURN; 109 110 virtual void ensure_parsability() { } 111 112 virtual void mangle_region(MemRegion mr) PRODUCT_RETURN; 113 114 // Boolean querries. 115 bool is_empty() const { return used_in_words() == 0; } 116 bool not_empty() const { return used_in_words() > 0; } 117 bool contains(const void* p) const { return _bottom <= p && p < _end; } 118 119 // Size computations. Sizes are in bytes. 120 size_t used_in_bytes() const { return used_in_words() * HeapWordSize; } 121 size_t free_in_bytes() const { return free_in_words() * HeapWordSize; } 122 123 // Size computations. Sizes are in heapwords. 124 virtual size_t used_in_words() const { return pointer_delta(top(), bottom()); } 125 virtual size_t free_in_words() const { return pointer_delta(end(), top()); } 126 virtual size_t tlab_capacity(Thread* thr) const { return capacity_in_bytes(); } 127 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const { return free_in_bytes(); } 128 129 // Allocation (return NULL if full) 130 virtual HeapWord* allocate(size_t word_size); 131 virtual HeapWord* cas_allocate(size_t word_size); 132 // Optional deallocation. Used in NUMA-allocator. 133 bool cas_deallocate(HeapWord *obj, size_t size); 134 135 // Iteration. 136 void oop_iterate(OopClosure* cl); 137 void object_iterate(ObjectClosure* cl); 138 139 // Debugging 140 virtual void print() const; 141 virtual void print_on(outputStream* st) const; 142 virtual void print_short() const; 143 virtual void print_short_on(outputStream* st) const; 144 virtual void verify(bool allow_dirty); 145 }; 146 147 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_MUTABLESPACE_HPP