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hotspot/src/share/vm/gc_implementation/shared/markSweep.cpp

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+/*
+ * Copyright 1997-2005 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.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_markSweep.cpp.incl"
+
+GrowableArray<oop>*     MarkSweep::_marking_stack       = NULL;
+GrowableArray<Klass*>*  MarkSweep::_revisit_klass_stack = NULL;
+
+GrowableArray<oop>*     MarkSweep::_preserved_oop_stack = NULL;
+GrowableArray<markOop>* MarkSweep::_preserved_mark_stack= NULL;
+size_t                  MarkSweep::_preserved_count = 0;
+size_t                  MarkSweep::_preserved_count_max = 0;
+PreservedMark*          MarkSweep::_preserved_marks = NULL;
+ReferenceProcessor*     MarkSweep::_ref_processor   = NULL;
+
+#ifdef VALIDATE_MARK_SWEEP
+GrowableArray<oop*>*    MarkSweep::_root_refs_stack = NULL;
+GrowableArray<oop> *    MarkSweep::_live_oops = NULL;
+GrowableArray<oop> *    MarkSweep::_live_oops_moved_to = NULL;
+GrowableArray<size_t>*  MarkSweep::_live_oops_size = NULL;
+size_t                  MarkSweep::_live_oops_index = 0;
+size_t                  MarkSweep::_live_oops_index_at_perm = 0;
+GrowableArray<oop*>*    MarkSweep::_other_refs_stack = NULL;
+GrowableArray<oop*>*    MarkSweep::_adjusted_pointers = NULL;
+bool                    MarkSweep::_pointer_tracking = false;
+bool                    MarkSweep::_root_tracking = true;
+
+GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops = NULL;
+GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops_moved_to = NULL;
+GrowableArray<size_t>   * MarkSweep::_cur_gc_live_oops_size = NULL;
+GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops = NULL;
+GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops_moved_to = NULL;
+GrowableArray<size_t>   * MarkSweep::_last_gc_live_oops_size = NULL;
+#endif
+
+void MarkSweep::revisit_weak_klass_link(Klass* k) {
+  _revisit_klass_stack->push(k);
+}
+
+
+void MarkSweep::follow_weak_klass_links() {
+  // All klasses on the revisit stack are marked at this point.
+  // Update and follow all subklass, sibling and implementor links.
+  for (int i = 0; i < _revisit_klass_stack->length(); i++) {
+    _revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
+  }
+  follow_stack();
+}
+
+
+void MarkSweep::mark_and_follow(oop* p) {
+  assert(Universe::heap()->is_in_reserved(p),
+         "we should only be traversing objects here");
+  oop m = *p;
+  if (m != NULL && !m->mark()->is_marked()) {
+    mark_object(m);
+    m->follow_contents();  // Follow contents of the marked object
+  }
+}
+
+void MarkSweep::_mark_and_push(oop* p) {
+  // Push marked object, contents will be followed later
+  oop m = *p;
+  mark_object(m);
+  _marking_stack->push(m);
+}
+
+MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
+
+void MarkSweep::follow_root(oop* p) {
+  assert(!Universe::heap()->is_in_reserved(p),
+         "roots shouldn't be things within the heap");
+#ifdef VALIDATE_MARK_SWEEP
+  if (ValidateMarkSweep) {
+    guarantee(!_root_refs_stack->contains(p), "should only be in here once");
+    _root_refs_stack->push(p);
+  }
+#endif
+  oop m = *p;
+  if (m != NULL && !m->mark()->is_marked()) {
+    mark_object(m);
+    m->follow_contents();  // Follow contents of the marked object
+  }
+  follow_stack();
+}
+
+MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
+
+void MarkSweep::follow_stack() {
+  while (!_marking_stack->is_empty()) {
+    oop obj = _marking_stack->pop();
+    assert (obj->is_gc_marked(), "p must be marked");
+    obj->follow_contents();
+  }
+}
+
+MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
+
+
+// We preserve the mark which should be replaced at the end and the location that it
+// will go.  Note that the object that this markOop belongs to isn't currently at that
+// address but it will be after phase4
+void MarkSweep::preserve_mark(oop obj, markOop mark) {
+  // we try to store preserved marks in the to space of the new generation since this
+  // is storage which should be available.  Most of the time this should be sufficient
+  // space for the marks we need to preserve but if it isn't we fall back in using
+  // GrowableArrays to keep track of the overflow.
+  if (_preserved_count < _preserved_count_max) {
+    _preserved_marks[_preserved_count++].init(obj, mark);
+  } else {
+    if (_preserved_mark_stack == NULL) {
+      _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);
+      _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);
+    }
+    _preserved_mark_stack->push(mark);
+    _preserved_oop_stack->push(obj);
+  }
+}
+
+MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);
+MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);
+
+void MarkSweep::adjust_marks() {
+  assert(_preserved_oop_stack == NULL ||
+         _preserved_oop_stack->length() == _preserved_mark_stack->length(),
+         "inconsistent preserved oop stacks");
+
+  // adjust the oops we saved earlier
+  for (size_t i = 0; i < _preserved_count; i++) {
+    _preserved_marks[i].adjust_pointer();
+  }
+
+  // deal with the overflow stack
+  if (_preserved_oop_stack) {
+    for (int i = 0; i < _preserved_oop_stack->length(); i++) {
+      oop* p = _preserved_oop_stack->adr_at(i);
+      adjust_pointer(p);
+    }
+  }
+}
+
+void MarkSweep::restore_marks() {
+  assert(_preserved_oop_stack == NULL ||
+         _preserved_oop_stack->length() == _preserved_mark_stack->length(),
+         "inconsistent preserved oop stacks");
+  if (PrintGC && Verbose) {
+    gclog_or_tty->print_cr("Restoring %d marks", _preserved_count +
+                  (_preserved_oop_stack ? _preserved_oop_stack->length() : 0));
+  }
+
+  // restore the marks we saved earlier
+  for (size_t i = 0; i < _preserved_count; i++) {
+    _preserved_marks[i].restore();
+  }
+
+  // deal with the overflow
+  if (_preserved_oop_stack) {
+    for (int i = 0; i < _preserved_oop_stack->length(); i++) {
+      oop obj       = _preserved_oop_stack->at(i);
+      markOop mark  = _preserved_mark_stack->at(i);
+      obj->set_mark(mark);
+    }
+  }
+}
+
+#ifdef VALIDATE_MARK_SWEEP
+
+void MarkSweep::track_adjusted_pointer(oop* p, oop newobj, bool isroot) {
+  if (!ValidateMarkSweep)
+    return;
+
+  if (!isroot) {
+    if (_pointer_tracking) {
+      guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
+      _adjusted_pointers->remove(p);
+    }
+  } else {
+    ptrdiff_t index = _root_refs_stack->find(p);
+    if (index != -1) {
+      int l = _root_refs_stack->length();
+      if (l > 0 && l - 1 != index) {
+        oop* last = _root_refs_stack->pop();
+        assert(last != p, "should be different");
+        _root_refs_stack->at_put(index, last);
+      } else {
+        _root_refs_stack->remove(p);
+      }
+    }
+  }
+}
+
+
+void MarkSweep::check_adjust_pointer(oop* p) {
+  _adjusted_pointers->push(p);
+}
+
+
+class AdjusterTracker: public OopClosure {
+ public:
+  AdjusterTracker() {};
+  void do_oop(oop* o)   { MarkSweep::check_adjust_pointer(o); }
+};
+
+
+void MarkSweep::track_interior_pointers(oop obj) {
+  if (ValidateMarkSweep) {
+    _adjusted_pointers->clear();
+    _pointer_tracking = true;
+
+    AdjusterTracker checker;
+    obj->oop_iterate(&checker);
+  }
+}
+
+
+void MarkSweep::check_interior_pointers() {
+  if (ValidateMarkSweep) {
+    _pointer_tracking = false;
+    guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
+  }
+}
+
+
+void MarkSweep::reset_live_oop_tracking(bool at_perm) {
+  if (ValidateMarkSweep) {
+    guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
+    _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
+  }
+}
+
+
+void MarkSweep::register_live_oop(oop p, size_t size) {
+  if (ValidateMarkSweep) {
+    _live_oops->push(p);
+    _live_oops_size->push(size);
+    _live_oops_index++;
+  }
+}
+
+void MarkSweep::validate_live_oop(oop p, size_t size) {
+  if (ValidateMarkSweep) {
+    oop obj = _live_oops->at((int)_live_oops_index);
+    guarantee(obj == p, "should be the same object");
+    guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
+    _live_oops_index++;
+  }
+}
+
+void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,
+                                  HeapWord* compaction_top) {
+  assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
+         "should be moved to forwarded location");
+  if (ValidateMarkSweep) {
+    MarkSweep::validate_live_oop(oop(q), size);
+    _live_oops_moved_to->push(oop(compaction_top));
+  }
+  if (RecordMarkSweepCompaction) {
+    _cur_gc_live_oops->push(q);
+    _cur_gc_live_oops_moved_to->push(compaction_top);
+    _cur_gc_live_oops_size->push(size);
+  }
+}
+
+
+void MarkSweep::compaction_complete() {
+  if (RecordMarkSweepCompaction) {
+    GrowableArray<HeapWord*>* _tmp_live_oops          = _cur_gc_live_oops;
+    GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
+    GrowableArray<size_t>   * _tmp_live_oops_size     = _cur_gc_live_oops_size;
+
+    _cur_gc_live_oops           = _last_gc_live_oops;
+    _cur_gc_live_oops_moved_to  = _last_gc_live_oops_moved_to;
+    _cur_gc_live_oops_size      = _last_gc_live_oops_size;
+    _last_gc_live_oops          = _tmp_live_oops;
+    _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
+    _last_gc_live_oops_size     = _tmp_live_oops_size;
+  }
+}
+
+
+void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {
+  if (!RecordMarkSweepCompaction) {
+    tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
+    return;
+  }
+
+  if (_last_gc_live_oops == NULL) {
+    tty->print_cr("No compaction information gathered yet");
+    return;
+  }
+
+  for (int i = 0; i < _last_gc_live_oops->length(); i++) {
+    HeapWord* old_oop = _last_gc_live_oops->at(i);
+    size_t    sz      = _last_gc_live_oops_size->at(i);
+    if (old_oop <= q && q < (old_oop + sz)) {
+      HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
+      size_t offset = (q - old_oop);
+      tty->print_cr("Address " PTR_FORMAT, q);
+      tty->print_cr(" Was in oop " PTR_FORMAT ", size %d, at offset %d", old_oop, sz, offset);
+      tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
+      return;
+    }
+  }
+
+  tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
+}
+#endif //VALIDATE_MARK_SWEEP
+
+MarkSweep::IsAliveClosure MarkSweep::is_alive;
+
+void MarkSweep::KeepAliveClosure::do_oop(oop* p) {
+#ifdef VALIDATE_MARK_SWEEP
+  if (ValidateMarkSweep) {
+    if (!Universe::heap()->is_in_reserved(p)) {
+      _root_refs_stack->push(p);
+    } else {
+      _other_refs_stack->push(p);
+    }
+  }
+#endif
+  mark_and_push(p);
+}
+
+MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
+
+void marksweep_init() { /* empty */ }
+
+#ifndef PRODUCT
+
+void MarkSweep::trace(const char* msg) {
+  if (TraceMarkSweep)
+    gclog_or_tty->print("%s", msg);
+}
+
+#endif