duke@435: /*
duke@435:  * Copyright 2002 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: //
duke@435: // PSPromotionLAB is a parallel scavenge promotion lab. This class acts very
duke@435: // much like a MutableSpace. We couldn't embed a MutableSpace, though, as
duke@435: // it has a considerable number of asserts and invariants that are violated.
duke@435: //
duke@435: 
duke@435: class ObjectStartArray;
duke@435: 
duke@435: class PSPromotionLAB : public CHeapObj {
duke@435:  protected:
coleenp@548:   static size_t filler_header_size;
duke@435: 
duke@435:   enum LabState {
duke@435:     needs_flush,
duke@435:     flushed,
duke@435:     zero_size
duke@435:   };
duke@435: 
duke@435:   HeapWord* _top;
duke@435:   HeapWord* _bottom;
duke@435:   HeapWord* _end;
duke@435:   LabState _state;
duke@435: 
duke@435:   void set_top(HeapWord* value)    { _top = value; }
duke@435:   void set_bottom(HeapWord* value) { _bottom = value; }
duke@435:   void set_end(HeapWord* value)    { _end = value; }
duke@435: 
duke@435:   // The shared initialize code invokes this.
duke@435:   debug_only(virtual bool lab_is_valid(MemRegion lab) { return false; });
duke@435: 
duke@435:   PSPromotionLAB() : _top(NULL), _bottom(NULL), _end(NULL) { }
duke@435: 
duke@435:  public:
duke@435:   // Filling and flushing.
duke@435:   void initialize(MemRegion lab);
duke@435: 
duke@435:   virtual void flush();
duke@435: 
duke@435:   // Accessors
duke@435:   HeapWord* bottom() const           { return _bottom; }
duke@435:   HeapWord* end() const              { return _end;    }
duke@435:   HeapWord* top() const              { return _top;    }
duke@435: 
duke@435:   bool is_flushed()                  { return _state == flushed; }
duke@435: 
duke@435:   bool unallocate_object(oop obj);
duke@435: 
duke@435:   // Returns a subregion containing all objects in this space.
duke@435:   MemRegion used_region()            { return MemRegion(bottom(), top()); }
duke@435: 
duke@435:   // Boolean querries.
duke@435:   bool is_empty() const              { return used() == 0; }
duke@435:   bool not_empty() const             { return used() > 0; }
duke@435:   bool contains(const void* p) const { return _bottom <= p && p < _end; }
duke@435: 
duke@435:   // Size computations.  Sizes are in bytes.
duke@435:   size_t capacity() const            { return byte_size(bottom(), end()); }
duke@435:   size_t used() const                { return byte_size(bottom(), top()); }
duke@435:   size_t free() const                { return byte_size(top(),    end()); }
duke@435: };
duke@435: 
duke@435: class PSYoungPromotionLAB : public PSPromotionLAB {
duke@435:  public:
duke@435:   PSYoungPromotionLAB() { }
duke@435: 
duke@435:   // Not MT safe
duke@435:   HeapWord* allocate(size_t size) {
duke@435:     // Can't assert this, when young fills, we keep the LAB around, but flushed.
duke@435:     // assert(_state != flushed, "Sanity");
duke@435:     HeapWord* obj = top();
duke@435:     HeapWord* new_top = obj + size;
duke@435:     // The 'new_top>obj' check is needed to detect overflow of obj+size.
duke@435:     if (new_top > obj && new_top <= end()) {
duke@435:       set_top(new_top);
duke@435:       assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435:              "checking alignment");
duke@435:       return obj;
duke@435:     }
duke@435: 
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   debug_only(virtual bool lab_is_valid(MemRegion lab));
duke@435: };
duke@435: 
duke@435: class PSOldPromotionLAB : public PSPromotionLAB {
duke@435:  private:
duke@435:   ObjectStartArray* _start_array;
duke@435: 
duke@435:  public:
duke@435:   PSOldPromotionLAB() : _start_array(NULL) { }
duke@435:   PSOldPromotionLAB(ObjectStartArray* start_array) : _start_array(start_array) { }
duke@435: 
duke@435:   void set_start_array(ObjectStartArray* start_array) { _start_array = start_array; }
duke@435: 
duke@435:   void flush();
duke@435: 
duke@435:   // Not MT safe
duke@435:   HeapWord* allocate(size_t size) {
duke@435:     // Cannot test for this now that we're doing promotion failures
duke@435:     // assert(_state != flushed, "Sanity");
duke@435:     assert(_start_array != NULL, "Sanity");
duke@435:     HeapWord* obj = top();
duke@435:     HeapWord* new_top = obj + size;
duke@435:     // The 'new_top>obj' check is needed to detect overflow of obj+size.
duke@435:     if (new_top > obj && new_top <= end()) {
duke@435:       set_top(new_top);
duke@435:       assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435:              "checking alignment");
duke@435:       _start_array->allocate_block(obj);
duke@435:       return obj;
duke@435:     }
duke@435: 
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   debug_only(virtual bool lab_is_valid(MemRegion lab));
duke@435: };