Sat, 23 Nov 2013 12:25:13 +0100
8028128: Add a type safe alternative for working with counter based data
Reviewed-by: dholmes, egahlin
duke@435 | 1 | /* |
mikael@4153 | 2 | * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP |
stefank@2314 | 26 | #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP |
stefank@2314 | 27 | |
stefank@2314 | 28 | #include "gc_implementation/parallelScavenge/objectStartArray.hpp" |
stefank@2314 | 29 | #include "memory/allocation.hpp" |
stefank@2314 | 30 | |
duke@435 | 31 | // |
duke@435 | 32 | // PSPromotionLAB is a parallel scavenge promotion lab. This class acts very |
duke@435 | 33 | // much like a MutableSpace. We couldn't embed a MutableSpace, though, as |
duke@435 | 34 | // it has a considerable number of asserts and invariants that are violated. |
duke@435 | 35 | // |
duke@435 | 36 | |
duke@435 | 37 | class ObjectStartArray; |
duke@435 | 38 | |
zgu@3900 | 39 | class PSPromotionLAB : public CHeapObj<mtGC> { |
duke@435 | 40 | protected: |
coleenp@548 | 41 | static size_t filler_header_size; |
duke@435 | 42 | |
duke@435 | 43 | enum LabState { |
duke@435 | 44 | needs_flush, |
duke@435 | 45 | flushed, |
duke@435 | 46 | zero_size |
duke@435 | 47 | }; |
duke@435 | 48 | |
duke@435 | 49 | HeapWord* _top; |
duke@435 | 50 | HeapWord* _bottom; |
duke@435 | 51 | HeapWord* _end; |
duke@435 | 52 | LabState _state; |
duke@435 | 53 | |
duke@435 | 54 | void set_top(HeapWord* value) { _top = value; } |
duke@435 | 55 | void set_bottom(HeapWord* value) { _bottom = value; } |
duke@435 | 56 | void set_end(HeapWord* value) { _end = value; } |
duke@435 | 57 | |
duke@435 | 58 | // The shared initialize code invokes this. |
duke@435 | 59 | debug_only(virtual bool lab_is_valid(MemRegion lab) { return false; }); |
duke@435 | 60 | |
duke@435 | 61 | PSPromotionLAB() : _top(NULL), _bottom(NULL), _end(NULL) { } |
duke@435 | 62 | |
duke@435 | 63 | public: |
duke@435 | 64 | // Filling and flushing. |
duke@435 | 65 | void initialize(MemRegion lab); |
duke@435 | 66 | |
duke@435 | 67 | virtual void flush(); |
duke@435 | 68 | |
duke@435 | 69 | // Accessors |
duke@435 | 70 | HeapWord* bottom() const { return _bottom; } |
duke@435 | 71 | HeapWord* end() const { return _end; } |
duke@435 | 72 | HeapWord* top() const { return _top; } |
duke@435 | 73 | |
duke@435 | 74 | bool is_flushed() { return _state == flushed; } |
duke@435 | 75 | |
stefank@3181 | 76 | bool unallocate_object(HeapWord* obj, size_t obj_size); |
duke@435 | 77 | |
duke@435 | 78 | // Returns a subregion containing all objects in this space. |
duke@435 | 79 | MemRegion used_region() { return MemRegion(bottom(), top()); } |
duke@435 | 80 | |
duke@435 | 81 | // Boolean querries. |
duke@435 | 82 | bool is_empty() const { return used() == 0; } |
duke@435 | 83 | bool not_empty() const { return used() > 0; } |
duke@435 | 84 | bool contains(const void* p) const { return _bottom <= p && p < _end; } |
duke@435 | 85 | |
duke@435 | 86 | // Size computations. Sizes are in bytes. |
duke@435 | 87 | size_t capacity() const { return byte_size(bottom(), end()); } |
duke@435 | 88 | size_t used() const { return byte_size(bottom(), top()); } |
duke@435 | 89 | size_t free() const { return byte_size(top(), end()); } |
duke@435 | 90 | }; |
duke@435 | 91 | |
duke@435 | 92 | class PSYoungPromotionLAB : public PSPromotionLAB { |
duke@435 | 93 | public: |
duke@435 | 94 | PSYoungPromotionLAB() { } |
duke@435 | 95 | |
duke@435 | 96 | // Not MT safe |
duke@435 | 97 | HeapWord* allocate(size_t size) { |
duke@435 | 98 | // Can't assert this, when young fills, we keep the LAB around, but flushed. |
duke@435 | 99 | // assert(_state != flushed, "Sanity"); |
duke@435 | 100 | HeapWord* obj = top(); |
duke@435 | 101 | HeapWord* new_top = obj + size; |
duke@435 | 102 | // The 'new_top>obj' check is needed to detect overflow of obj+size. |
duke@435 | 103 | if (new_top > obj && new_top <= end()) { |
duke@435 | 104 | set_top(new_top); |
duke@435 | 105 | assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), |
duke@435 | 106 | "checking alignment"); |
duke@435 | 107 | return obj; |
duke@435 | 108 | } |
duke@435 | 109 | |
duke@435 | 110 | return NULL; |
duke@435 | 111 | } |
duke@435 | 112 | |
duke@435 | 113 | debug_only(virtual bool lab_is_valid(MemRegion lab)); |
duke@435 | 114 | }; |
duke@435 | 115 | |
duke@435 | 116 | class PSOldPromotionLAB : public PSPromotionLAB { |
duke@435 | 117 | private: |
duke@435 | 118 | ObjectStartArray* _start_array; |
duke@435 | 119 | |
duke@435 | 120 | public: |
duke@435 | 121 | PSOldPromotionLAB() : _start_array(NULL) { } |
duke@435 | 122 | PSOldPromotionLAB(ObjectStartArray* start_array) : _start_array(start_array) { } |
duke@435 | 123 | |
duke@435 | 124 | void set_start_array(ObjectStartArray* start_array) { _start_array = start_array; } |
duke@435 | 125 | |
duke@435 | 126 | void flush(); |
duke@435 | 127 | |
duke@435 | 128 | // Not MT safe |
duke@435 | 129 | HeapWord* allocate(size_t size) { |
duke@435 | 130 | // Cannot test for this now that we're doing promotion failures |
duke@435 | 131 | // assert(_state != flushed, "Sanity"); |
duke@435 | 132 | assert(_start_array != NULL, "Sanity"); |
duke@435 | 133 | HeapWord* obj = top(); |
duke@435 | 134 | HeapWord* new_top = obj + size; |
duke@435 | 135 | // The 'new_top>obj' check is needed to detect overflow of obj+size. |
duke@435 | 136 | if (new_top > obj && new_top <= end()) { |
duke@435 | 137 | set_top(new_top); |
duke@435 | 138 | assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), |
duke@435 | 139 | "checking alignment"); |
duke@435 | 140 | _start_array->allocate_block(obj); |
duke@435 | 141 | return obj; |
duke@435 | 142 | } |
duke@435 | 143 | |
duke@435 | 144 | return NULL; |
duke@435 | 145 | } |
duke@435 | 146 | |
duke@435 | 147 | debug_only(virtual bool lab_is_valid(MemRegion lab)); |
duke@435 | 148 | }; |
stefank@2314 | 149 | |
stefank@2314 | 150 | #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP |