jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@2d160770d2e5 (annotated)

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@2d160770d2e5 (annotated)

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp

Mon, 02 Aug 2010 12:51:43 -0700

author: johnc
date: Mon, 02 Aug 2010 12:51:43 -0700
changeset 2060: 2d160770d2e5
parent 1907: c18cbe5936b8
child 2191: 894b1d7c7e01
permissions: -rw-r--r--

6814437: G1: remove the _new_refs array
Summary: The per-worker _new_refs array is used to hold references that point into the collection set. It is populated during RSet updating and subsequently processed. In the event of an evacuation failure it processed again to recreate the RSets of regions in the collection set. Remove the per-worker _new_refs array by processing the references directly. Use a DirtyCardQueue to hold the cards containing the references so that the RSets of regions in the collection set can be recreated when handling an evacuation failure.
Reviewed-by: iveresov, jmasa, tonyp

 /*
  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.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");
   SharedHeap* sh = SharedHeap::heap();
 #ifdef ASSERT
   if (sh->collector_policy()->should_clear_all_soft_refs()) {
     assert(clear_all_softrefs, "Policy should have been checked earler");
   }
 #endif
   // hook up weak ref data so it can be used during Mark-Sweep
   assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
   assert(rp != NULL, "should be non-NULL");
   GenMarkSweep::_ref_processor = rp;
   rp->setup_policy(clear_all_softrefs);
   // 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.
   sh->perm_gen()->stat_record()->invocations++;
   bool marked_for_unloading = false;
   allocate_stacks();
   // We should save the marks of the currently locked biased monitors.
   // The marking doesn't preserve the marks of biased objects.
   BiasedLocking::preserve_marks();
   mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
   if (VerifyDuringGC) {
       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();
   BiasedLocking::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);
   GenMarkSweep::_objarray_stack =
     new (ResourceObj::C_HEAP) GrowableArray<ObjArrayTask>(50, true);
   int size = SystemDictionary::number_of_classes() * 2;
   GenMarkSweep::_revisit_klass_stack =
     new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
   // (#klass/k)^2 for k ~ 10 appears a better fit, but this will have to do
   // for now until we have a chance to work out a more optimal setting.
   GenMarkSweep::_revisit_mdo_stack =
     new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, 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,  // activeate StrongRootsScope
                            true,  // Collecting permanent generation.
                            SharedHeap::SO_SystemClasses,
                            &GenMarkSweep::follow_root_closure,
                            &GenMarkSweep::follow_code_root_closure,
                            &GenMarkSweep::follow_root_closure);
   // Process reference objects found during marking
   ReferenceProcessor* rp = GenMarkSweep::ref_processor();
   rp->setup_policy(clear_all_softrefs);
   rp->process_discovered_references(&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 memoized MDO's and clear any unmarked weak refs
   GenMarkSweep::follow_mdo_weak_refs();
   assert(GenMarkSweep::_marking_stack->is_empty(), "just drained");
   // 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;
   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) :
     _cp(NULL, cs, cs->initialize_threshold()),
     _mrbs(G1CollectedHeap::heap()->mr_bs())
   {}
   bool doHeapRegion(HeapRegion* hr) {
     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;
   }
 };
 // Finds the first HeapRegion.
 class FindFirstRegionClosure: public HeapRegionClosure {
   HeapRegion* _a_region;
 public:
   FindFirstRegionClosure() : _a_region(NULL) {}
   bool doHeapRegion(HeapRegion* r) {
     _a_region = r;
     return true;
   }
   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");
   FindFirstRegionClosure cl;
   g1h->heap_region_iterate(&cl);
   HeapRegion *r = cl.result();
   CompactibleSpace* sp = r;
   if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
     sp = r->next_compaction_space();
   }
   G1PrepareCompactClosure blk(sp);
   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,  // activate StrongRootsScope
                            true,  // Collecting permanent generation.
                            SharedHeap::SO_AllClasses,
                            &GenMarkSweep::adjust_root_pointer_closure,
                            NULL,  // do not touch code cache here
                            &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: ***

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@2d160770d2e5 (annotated)

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp