Mercurial > hg > truffle
diff src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.hpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,142 @@ +/* + * Copyright 2002 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// +// PSPromotionLAB is a parallel scavenge promotion lab. This class acts very +// much like a MutableSpace. We couldn't embed a MutableSpace, though, as +// it has a considerable number of asserts and invariants that are violated. +// + +class ObjectStartArray; + +class PSPromotionLAB : public CHeapObj { + protected: + static const size_t filler_header_size; + + enum LabState { + needs_flush, + flushed, + zero_size + }; + + HeapWord* _top; + HeapWord* _bottom; + HeapWord* _end; + LabState _state; + + void set_top(HeapWord* value) { _top = value; } + void set_bottom(HeapWord* value) { _bottom = value; } + void set_end(HeapWord* value) { _end = value; } + + // The shared initialize code invokes this. + debug_only(virtual bool lab_is_valid(MemRegion lab) { return false; }); + + PSPromotionLAB() : _top(NULL), _bottom(NULL), _end(NULL) { } + + public: + // Filling and flushing. + void initialize(MemRegion lab); + + virtual void flush(); + + // Accessors + HeapWord* bottom() const { return _bottom; } + HeapWord* end() const { return _end; } + HeapWord* top() const { return _top; } + + bool is_flushed() { return _state == flushed; } + + bool unallocate_object(oop obj); + + // Returns a subregion containing all objects in this space. + MemRegion used_region() { return MemRegion(bottom(), top()); } + + // Boolean querries. + bool is_empty() const { return used() == 0; } + bool not_empty() const { return used() > 0; } + bool contains(const void* p) const { return _bottom <= p && p < _end; } + + // Size computations. Sizes are in bytes. + size_t capacity() const { return byte_size(bottom(), end()); } + size_t used() const { return byte_size(bottom(), top()); } + size_t free() const { return byte_size(top(), end()); } +}; + +class PSYoungPromotionLAB : public PSPromotionLAB { + public: + PSYoungPromotionLAB() { } + + // Not MT safe + HeapWord* allocate(size_t size) { + // Can't assert this, when young fills, we keep the LAB around, but flushed. + // assert(_state != flushed, "Sanity"); + HeapWord* obj = top(); + HeapWord* new_top = obj + size; + // The 'new_top>obj' check is needed to detect overflow of obj+size. + if (new_top > obj && new_top <= end()) { + set_top(new_top); + assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), + "checking alignment"); + return obj; + } + + return NULL; + } + + debug_only(virtual bool lab_is_valid(MemRegion lab)); +}; + +class PSOldPromotionLAB : public PSPromotionLAB { + private: + ObjectStartArray* _start_array; + + public: + PSOldPromotionLAB() : _start_array(NULL) { } + PSOldPromotionLAB(ObjectStartArray* start_array) : _start_array(start_array) { } + + void set_start_array(ObjectStartArray* start_array) { _start_array = start_array; } + + void flush(); + + // Not MT safe + HeapWord* allocate(size_t size) { + // Cannot test for this now that we're doing promotion failures + // assert(_state != flushed, "Sanity"); + assert(_start_array != NULL, "Sanity"); + HeapWord* obj = top(); + HeapWord* new_top = obj + size; + // The 'new_top>obj' check is needed to detect overflow of obj+size. + if (new_top > obj && new_top <= end()) { + set_top(new_top); + assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top), + "checking alignment"); + _start_array->allocate_block(obj); + return obj; + } + + return NULL; + } + + debug_only(virtual bool lab_is_valid(MemRegion lab)); +};