--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1MarkSweep.cpp Thu Jun 05 15:57:56 2008 -0700
@@ -0,0 +1,381 @@
+/*
+ * Copyright 2001-2007 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/_g1MarkSweep.cpp.incl"
+
+class HeapRegion;
+
+void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp,
+ bool clear_all_softrefs) {
+ assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
+
+ // hook up weak ref data so it can be used during Mark-Sweep
+ assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
+ GenMarkSweep::_ref_processor = rp;
+ assert(rp != NULL, "should be non-NULL");
+
+ // When collecting the permanent generation methodOops may be moving,
+ // so we either have to flush all bcp data or convert it into bci.
+ CodeCache::gc_prologue();
+ Threads::gc_prologue();
+
+ // Increment the invocation count for the permanent generation, since it is
+ // implicitly collected whenever we do a full mark sweep collection.
+ SharedHeap* sh = SharedHeap::heap();
+ sh->perm_gen()->stat_record()->invocations++;
+
+ bool marked_for_unloading = false;
+
+ allocate_stacks();
+
+ mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
+
+ if (G1VerifyConcMark) {
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ g1h->checkConcurrentMark();
+ }
+
+ mark_sweep_phase2();
+
+ // Don't add any more derived pointers during phase3
+ COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
+
+ mark_sweep_phase3();
+
+ mark_sweep_phase4();
+
+ GenMarkSweep::restore_marks();
+
+ GenMarkSweep::deallocate_stacks();
+
+ // We must invalidate the perm-gen rs, so that it gets rebuilt.
+ GenRemSet* rs = sh->rem_set();
+ rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/);
+
+ // "free at last gc" is calculated from these.
+ // CHF: cheating for now!!!
+ // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity());
+ // Universe::set_heap_used_at_last_gc(Universe::heap()->used());
+
+ Threads::gc_epilogue();
+ CodeCache::gc_epilogue();
+
+ // refs processing: clean slate
+ GenMarkSweep::_ref_processor = NULL;
+}
+
+
+void G1MarkSweep::allocate_stacks() {
+ GenMarkSweep::_preserved_count_max = 0;
+ GenMarkSweep::_preserved_marks = NULL;
+ GenMarkSweep::_preserved_count = 0;
+ GenMarkSweep::_preserved_mark_stack = NULL;
+ GenMarkSweep::_preserved_oop_stack = NULL;
+
+ GenMarkSweep::_marking_stack =
+ new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
+
+ size_t size = SystemDictionary::number_of_classes() * 2;
+ GenMarkSweep::_revisit_klass_stack =
+ new (ResourceObj::C_HEAP) GrowableArray<Klass*>((int)size, true);
+}
+
+void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
+ bool clear_all_softrefs) {
+ // Recursively traverse all live objects and mark them
+ EventMark m("1 mark object");
+ TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty);
+ GenMarkSweep::trace(" 1");
+
+ SharedHeap* sh = SharedHeap::heap();
+
+ sh->process_strong_roots(true, // Collecting permanent generation.
+ SharedHeap::SO_SystemClasses,
+ &GenMarkSweep::follow_root_closure,
+ &GenMarkSweep::follow_root_closure);
+
+ // Process reference objects found during marking
+ ReferencePolicy *soft_ref_policy;
+ if (clear_all_softrefs) {
+ soft_ref_policy = new AlwaysClearPolicy();
+ } else {
+#ifdef COMPILER2
+ soft_ref_policy = new LRUMaxHeapPolicy();
+#else
+ soft_ref_policy = new LRUCurrentHeapPolicy();
+#endif
+ }
+ assert(soft_ref_policy != NULL,"No soft reference policy");
+ GenMarkSweep::ref_processor()->process_discovered_references(
+ soft_ref_policy,
+ &GenMarkSweep::is_alive,
+ &GenMarkSweep::keep_alive,
+ &GenMarkSweep::follow_stack_closure,
+ NULL);
+
+ // Follow system dictionary roots and unload classes
+ bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
+ assert(GenMarkSweep::_marking_stack->is_empty(),
+ "stack should be empty by now");
+
+ // Follow code cache roots (has to be done after system dictionary,
+ // assumes all live klasses are marked)
+ CodeCache::do_unloading(&GenMarkSweep::is_alive,
+ &GenMarkSweep::keep_alive,
+ purged_class);
+ GenMarkSweep::follow_stack();
+
+ // Update subklass/sibling/implementor links of live klasses
+ GenMarkSweep::follow_weak_klass_links();
+ assert(GenMarkSweep::_marking_stack->is_empty(),
+ "stack should be empty by now");
+
+ // Visit symbol and interned string tables and delete unmarked oops
+ SymbolTable::unlink(&GenMarkSweep::is_alive);
+ StringTable::unlink(&GenMarkSweep::is_alive);
+
+ assert(GenMarkSweep::_marking_stack->is_empty(),
+ "stack should be empty by now");
+}
+
+class G1PrepareCompactClosure: public HeapRegionClosure {
+ ModRefBarrierSet* _mrbs;
+ CompactPoint _cp;
+ bool _popular_only;
+
+ void free_humongous_region(HeapRegion* hr) {
+ HeapWord* bot = hr->bottom();
+ HeapWord* end = hr->end();
+ assert(hr->startsHumongous(),
+ "Only the start of a humongous region should be freed.");
+ G1CollectedHeap::heap()->free_region(hr);
+ hr->prepare_for_compaction(&_cp);
+ // Also clear the part of the card table that will be unused after
+ // compaction.
+ _mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
+ }
+
+public:
+ G1PrepareCompactClosure(CompactibleSpace* cs, bool popular_only) :
+ _cp(NULL, cs, cs->initialize_threshold()),
+ _mrbs(G1CollectedHeap::heap()->mr_bs()),
+ _popular_only(popular_only)
+ {}
+ bool doHeapRegion(HeapRegion* hr) {
+ if (_popular_only && !hr->popular())
+ return true; // terminate early
+ else if (!_popular_only && hr->popular())
+ return false; // skip this one.
+
+ if (hr->isHumongous()) {
+ if (hr->startsHumongous()) {
+ oop obj = oop(hr->bottom());
+ if (obj->is_gc_marked()) {
+ obj->forward_to(obj);
+ } else {
+ free_humongous_region(hr);
+ }
+ } else {
+ assert(hr->continuesHumongous(), "Invalid humongous.");
+ }
+ } else {
+ hr->prepare_for_compaction(&_cp);
+ // Also clear the part of the card table that will be unused after
+ // compaction.
+ _mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
+ }
+ return false;
+ }
+};
+// Stolen verbatim from g1CollectedHeap.cpp
+class FindFirstRegionClosure: public HeapRegionClosure {
+ HeapRegion* _a_region;
+ bool _find_popular;
+public:
+ FindFirstRegionClosure(bool find_popular) :
+ _a_region(NULL), _find_popular(find_popular) {}
+ bool doHeapRegion(HeapRegion* r) {
+ if (r->popular() == _find_popular) {
+ _a_region = r;
+ return true;
+ } else {
+ return false;
+ }
+ }
+ HeapRegion* result() { return _a_region; }
+};
+
+void G1MarkSweep::mark_sweep_phase2() {
+ // Now all live objects are marked, compute the new object addresses.
+
+ // It is imperative that we traverse perm_gen LAST. If dead space is
+ // allowed a range of dead object may get overwritten by a dead int
+ // array. If perm_gen is not traversed last a klassOop may get
+ // overwritten. This is fine since it is dead, but if the class has dead
+ // instances we have to skip them, and in order to find their size we
+ // need the klassOop!
+ //
+ // It is not required that we traverse spaces in the same order in
+ // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
+ // tracking expects us to do so. See comment under phase4.
+
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ Generation* pg = g1h->perm_gen();
+
+ EventMark m("2 compute new addresses");
+ TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty);
+ GenMarkSweep::trace("2");
+
+ // First we compact the popular regions.
+ if (G1NumPopularRegions > 0) {
+ CompactibleSpace* sp = g1h->first_compactible_space();
+ FindFirstRegionClosure cl(true /*find_popular*/);
+ g1h->heap_region_iterate(&cl);
+ HeapRegion *r = cl.result();
+ assert(r->popular(), "should have found a popular region.");
+ assert(r == sp, "first popular heap region should "
+ "== first compactible space");
+ G1PrepareCompactClosure blk(sp, true/*popular_only*/);
+ g1h->heap_region_iterate(&blk);
+ }
+
+ // Now we do the regular regions.
+ FindFirstRegionClosure cl(false /*find_popular*/);
+ g1h->heap_region_iterate(&cl);
+ HeapRegion *r = cl.result();
+ assert(!r->popular(), "should have founda non-popular region.");
+ CompactibleSpace* sp = r;
+ if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
+ sp = r->next_compaction_space();
+ }
+
+ G1PrepareCompactClosure blk(sp, false/*popular_only*/);
+ g1h->heap_region_iterate(&blk);
+
+ CompactPoint perm_cp(pg, NULL, NULL);
+ pg->prepare_for_compaction(&perm_cp);
+}
+
+class G1AdjustPointersClosure: public HeapRegionClosure {
+ public:
+ bool doHeapRegion(HeapRegion* r) {
+ if (r->isHumongous()) {
+ if (r->startsHumongous()) {
+ // We must adjust the pointers on the single H object.
+ oop obj = oop(r->bottom());
+ debug_only(GenMarkSweep::track_interior_pointers(obj));
+ // point all the oops to the new location
+ obj->adjust_pointers();
+ debug_only(GenMarkSweep::check_interior_pointers());
+ }
+ } else {
+ // This really ought to be "as_CompactibleSpace"...
+ r->adjust_pointers();
+ }
+ return false;
+ }
+};
+
+void G1MarkSweep::mark_sweep_phase3() {
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ Generation* pg = g1h->perm_gen();
+
+ // Adjust the pointers to reflect the new locations
+ EventMark m("3 adjust pointers");
+ TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty);
+ GenMarkSweep::trace("3");
+
+ SharedHeap* sh = SharedHeap::heap();
+
+ sh->process_strong_roots(true, // Collecting permanent generation.
+ SharedHeap::SO_AllClasses,
+ &GenMarkSweep::adjust_root_pointer_closure,
+ &GenMarkSweep::adjust_pointer_closure);
+
+ g1h->ref_processor()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure);
+
+ // Now adjust pointers in remaining weak roots. (All of which should
+ // have been cleared if they pointed to non-surviving objects.)
+ g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure,
+ &GenMarkSweep::adjust_pointer_closure);
+
+ GenMarkSweep::adjust_marks();
+
+ G1AdjustPointersClosure blk;
+ g1h->heap_region_iterate(&blk);
+ pg->adjust_pointers();
+}
+
+class G1SpaceCompactClosure: public HeapRegionClosure {
+public:
+ G1SpaceCompactClosure() {}
+
+ bool doHeapRegion(HeapRegion* hr) {
+ if (hr->isHumongous()) {
+ if (hr->startsHumongous()) {
+ oop obj = oop(hr->bottom());
+ if (obj->is_gc_marked()) {
+ obj->init_mark();
+ } else {
+ assert(hr->is_empty(), "Should have been cleared in phase 2.");
+ }
+ hr->reset_during_compaction();
+ }
+ } else {
+ hr->compact();
+ }
+ return false;
+ }
+};
+
+void G1MarkSweep::mark_sweep_phase4() {
+ // All pointers are now adjusted, move objects accordingly
+
+ // It is imperative that we traverse perm_gen first in phase4. All
+ // classes must be allocated earlier than their instances, and traversing
+ // perm_gen first makes sure that all klassOops have moved to their new
+ // location before any instance does a dispatch through it's klass!
+
+ // The ValidateMarkSweep live oops tracking expects us to traverse spaces
+ // in the same order in phase2, phase3 and phase4. We don't quite do that
+ // here (perm_gen first rather than last), so we tell the validate code
+ // to use a higher index (saved from phase2) when verifying perm_gen.
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ Generation* pg = g1h->perm_gen();
+
+ EventMark m("4 compact heap");
+ TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty);
+ GenMarkSweep::trace("4");
+
+ pg->compact();
+
+ G1SpaceCompactClosure blk;
+ g1h->heap_region_iterate(&blk);
+
+}
+
+// Local Variables: ***
+// c-indentation-style: gnu ***
+// End: ***