1 /* 2 * Copyright (c) 2001, 2009, 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 // A MutableSpace is a subtype of ImmutableSpace that supports the 26 // concept of allocation. This includes the concepts that a space may 27 // be only partially full, and the querry methods that go with such 28 // an assumption. MutableSpace is also responsible for minimizing the 29 // page allocation time by having the memory pretouched (with 30 // AlwaysPretouch) and for optimizing page placement on NUMA systems 31 // by make the underlying region interleaved (with UseNUMA). 32 // 33 // Invariant: (ImmutableSpace +) bottom() <= top() <= end() 34 // top() is inclusive and end() is exclusive. 35 36 class MutableSpaceMangler; 37 38 class MutableSpace: public ImmutableSpace { 39 friend class VMStructs; 40 41 // Helper for mangling unused space in debug builds 42 MutableSpaceMangler* _mangler; 43 // The last region which page had been setup to be interleaved. 44 MemRegion _last_setup_region; 45 size_t _alignment; 46 protected: 47 HeapWord* _top; 48 49 MutableSpaceMangler* mangler() { return _mangler; } 50 51 void numa_setup_pages(MemRegion mr, bool clear_space); 52 void pretouch_pages(MemRegion mr); 53 54 void set_last_setup_region(MemRegion mr) { _last_setup_region = mr; } 55 MemRegion last_setup_region() const { return _last_setup_region; } 56 57 public: 58 virtual ~MutableSpace(); 59 MutableSpace(size_t page_size); 60 61 // Accessors 62 HeapWord* top() const { return _top; } 63 virtual void set_top(HeapWord* value) { _top = value; } 64 65 HeapWord** top_addr() { return &_top; } 66 HeapWord** end_addr() { return &_end; } 67 68 virtual void set_bottom(HeapWord* value) { _bottom = value; } 69 virtual void set_end(HeapWord* value) { _end = value; } 70 71 size_t alignment() { return _alignment; } 72 73 // Returns a subregion containing all objects in this space. 74 MemRegion used_region() { return MemRegion(bottom(), top()); } 75 76 static const bool SetupPages = true; 77 static const bool DontSetupPages = false; 78 79 // Initialization 80 virtual void initialize(MemRegion mr, 81 bool clear_space, 82 bool mangle_space, 83 bool setup_pages = SetupPages); 84 85 virtual void clear(bool mangle_space); 86 // Does the usual initialization but optionally resets top to bottom. 87 #if 0 // MANGLE_SPACE 88 void initialize(MemRegion mr, bool clear_space, bool reset_top); 89 #endif 90 virtual void update() { } 91 virtual void accumulate_statistics() { } 92 93 // Methods used in mangling. See descriptions under SpaceMangler. 94 virtual void mangle_unused_area() PRODUCT_RETURN; 95 virtual void mangle_unused_area_complete() PRODUCT_RETURN; 96 virtual void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; 97 virtual void check_mangled_unused_area_complete() PRODUCT_RETURN; 98 virtual void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; 99 100 // Used to save the space's current top for later use during mangling. 101 virtual void set_top_for_allocations() PRODUCT_RETURN; 102 103 virtual void ensure_parsability() { } 104 105 virtual void mangle_region(MemRegion mr) PRODUCT_RETURN; 106 107 // Boolean querries. 108 bool is_empty() const { return used_in_words() == 0; } 109 bool not_empty() const { return used_in_words() > 0; } 110 bool contains(const void* p) const { return _bottom <= p && p < _end; } 111 112 // Size computations. Sizes are in bytes. 113 size_t used_in_bytes() const { return used_in_words() * HeapWordSize; } 114 size_t free_in_bytes() const { return free_in_words() * HeapWordSize; } 115 116 // Size computations. Sizes are in heapwords. 117 virtual size_t used_in_words() const { return pointer_delta(top(), bottom()); } 118 virtual size_t free_in_words() const { return pointer_delta(end(), top()); } 119 virtual size_t tlab_capacity(Thread* thr) const { return capacity_in_bytes(); } 120 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const { return free_in_bytes(); } 121 122 // Allocation (return NULL if full) 123 virtual HeapWord* allocate(size_t word_size); 124 virtual HeapWord* cas_allocate(size_t word_size); 125 // Optional deallocation. Used in NUMA-allocator. 126 bool cas_deallocate(HeapWord *obj, size_t size); 127 128 // Iteration. 129 void oop_iterate(OopClosure* cl); 130 void object_iterate(ObjectClosure* cl); 131 132 // Debugging 133 virtual void print() const; 134 virtual void print_on(outputStream* st) const; 135 virtual void print_short() const; 136 virtual void print_short_on(outputStream* st) const; 137 virtual void verify(bool allow_dirty); 138 };