--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/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));
+};