jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@595c0f60d50d (annotated)

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@595c0f60d50d (annotated)

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

Tue, 18 Mar 2014 19:07:22 +0100

author: pliden
date: Tue, 18 Mar 2014 19:07:22 +0100
changeset 6413: 595c0f60d50d
parent 6385: 58fc1b1523dc
child 6876: 710a3c8b516e
child 6904: 0982ec23da03
permissions: -rw-r--r--

8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp

 /*
  * Copyright (c) 2001, 2014, 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 "precompiled.hpp"
 #include "classfile/javaClasses.hpp"
 #include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "classfile/vmSymbols.hpp"
 #include "code/codeCache.hpp"
 #include "code/icBuffer.hpp"
 #include "gc_implementation/g1/g1Log.hpp"
 #include "gc_implementation/g1/g1MarkSweep.hpp"
 #include "gc_implementation/g1/g1StringDedup.hpp"
 #include "gc_implementation/shared/gcHeapSummary.hpp"
 #include "gc_implementation/shared/gcTimer.hpp"
 #include "gc_implementation/shared/gcTrace.hpp"
 #include "gc_implementation/shared/gcTraceTime.hpp"
 #include "memory/gcLocker.hpp"
 #include "memory/genCollectedHeap.hpp"
 #include "memory/modRefBarrierSet.hpp"
 #include "memory/referencePolicy.hpp"
 #include "memory/space.hpp"
 #include "oops/instanceRefKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiExport.hpp"
 #include "runtime/biasedLocking.hpp"
 #include "runtime/fprofiler.hpp"
 #include "runtime/synchronizer.hpp"
 #include "runtime/thread.hpp"
 #include "runtime/vmThread.hpp"
 #include "utilities/copy.hpp"
 #include "utilities/events.hpp"
 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");
   assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Precondition");
   GenMarkSweep::_ref_processor = rp;
   rp->setup_policy(clear_all_softrefs);
   // When collecting the permanent generation Method*s may be moving,
   // so we either have to flush all bcp data or convert it into bci.
   CodeCache::gc_prologue();
   Threads::gc_prologue();
   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);
   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();
   // "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();
   JvmtiExport::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;
 }
 void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
                                     bool clear_all_softrefs) {
   // Recursively traverse all live objects and mark them
   GCTraceTime tm("phase 1", G1Log::fine() && Verbose, true, gc_timer());
   GenMarkSweep::trace(" 1");
   SharedHeap* sh = SharedHeap::heap();
   // Need cleared claim bits for the strong roots processing
   ClassLoaderDataGraph::clear_claimed_marks();
   sh->process_strong_roots(true,  // activate StrongRootsScope
                            false, // not scavenging.
                            SharedHeap::SO_SystemClasses,
                            &GenMarkSweep::follow_root_closure,
                            &GenMarkSweep::follow_code_root_closure,
                            &GenMarkSweep::follow_klass_closure);
   // Process reference objects found during marking
   ReferenceProcessor* rp = GenMarkSweep::ref_processor();
   assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Sanity");
   rp->setup_policy(clear_all_softrefs);
   const ReferenceProcessorStats& stats =
     rp->process_discovered_references(&GenMarkSweep::is_alive,
                                       &GenMarkSweep::keep_alive,
                                       &GenMarkSweep::follow_stack_closure,
                                       NULL,
                                       gc_timer());
   gc_tracer()->report_gc_reference_stats(stats);
   // This is the point where the entire marking should have completed.
   assert(GenMarkSweep::_marking_stack.is_empty(), "Marking should have completed");
   // Unload classes and purge the SystemDictionary.
   bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
   // Unload nmethods.
   CodeCache::do_unloading(&GenMarkSweep::is_alive, purged_class);
   // Prune dead klasses from subklass/sibling/implementor lists.
   Klass::clean_weak_klass_links(&GenMarkSweep::is_alive);
   // Delete entries for dead interned string and clean up unreferenced symbols in symbol table.
   G1CollectedHeap::heap()->unlink_string_and_symbol_table(&GenMarkSweep::is_alive);
   if (VerifyDuringGC) {
     HandleMark hm;  // handle scope
     COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact);
     Universe::heap()->prepare_for_verify();
     // Note: we can verify only the heap here. When an object is
     // marked, the previous value of the mark word (including
     // identity hash values, ages, etc) is preserved, and the mark
     // word is set to markOop::marked_value - effectively removing
     // any hash values from the mark word. These hash values are
     // used when verifying the dictionaries and so removing them
     // from the mark word can make verification of the dictionaries
     // fail. At the end of the GC, the orginal mark word values
     // (including hash values) are restored to the appropriate
     // objects.
     if (!VerifySilently) {
       gclog_or_tty->print(" VerifyDuringGC:(full)[Verifying ");
     }
     Universe::heap()->verify(VerifySilently, VerifyOption_G1UseMarkWord);
     if (!VerifySilently) {
       gclog_or_tty->print_cr("]");
     }
   }
   gc_tracer()->report_object_count_after_gc(&GenMarkSweep::is_alive);
 }
 class G1PrepareCompactClosure: public HeapRegionClosure {
   G1CollectedHeap* _g1h;
   ModRefBarrierSet* _mrbs;
   CompactPoint _cp;
   HeapRegionSetCount _humongous_regions_removed;
   void free_humongous_region(HeapRegion* hr) {
     HeapWord* end = hr->end();
     FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep");
     assert(hr->startsHumongous(),
            "Only the start of a humongous region should be freed.");
     hr->set_containing_set(NULL);
     _humongous_regions_removed.increment(1u, hr->capacity());
     _g1h->free_humongous_region(hr, &dummy_free_list, false /* par */);
     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(), end));
     dummy_free_list.remove_all();
   }
 public:
   G1PrepareCompactClosure(CompactibleSpace* cs)
   : _g1h(G1CollectedHeap::heap()),
     _mrbs(_g1h->g1_barrier_set()),
     _cp(NULL, cs, cs->initialize_threshold()),
     _humongous_regions_removed() { }
   void update_sets() {
     // We'll recalculate total used bytes and recreate the free list
     // at the end of the GC, so no point in updating those values here.
     HeapRegionSetCount empty_set;
     _g1h->remove_from_old_sets(empty_set, _humongous_regions_removed);
   }
   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;
   }
 };
 void G1MarkSweep::mark_sweep_phase2() {
   // Now all live objects are marked, compute the new object addresses.
   // 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();
   GCTraceTime tm("phase 2", G1Log::fine() && Verbose, true, gc_timer());
   GenMarkSweep::trace("2");
   // find the first region
   HeapRegion* r = g1h->region_at(0);
   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);
   blk.update_sets();
 }
 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());
         // point all the oops to the new location
         obj->adjust_pointers();
       }
     } else {
       // This really ought to be "as_CompactibleSpace"...
       r->adjust_pointers();
     }
     return false;
   }
 };
 void G1MarkSweep::mark_sweep_phase3() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   // Adjust the pointers to reflect the new locations
   GCTraceTime tm("phase 3", G1Log::fine() && Verbose, true, gc_timer());
   GenMarkSweep::trace("3");
   SharedHeap* sh = SharedHeap::heap();
   // Need cleared claim bits for the strong roots processing
   ClassLoaderDataGraph::clear_claimed_marks();
   sh->process_strong_roots(true,  // activate StrongRootsScope
                            false, // not scavenging.
                            SharedHeap::SO_AllClasses,
                            &GenMarkSweep::adjust_pointer_closure,
                            NULL,  // do not touch code cache here
                            &GenMarkSweep::adjust_klass_closure);
   assert(GenMarkSweep::ref_processor() == g1h->ref_processor_stw(), "Sanity");
   g1h->ref_processor_stw()->weak_oops_do(&GenMarkSweep::adjust_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_pointer_closure);
   if (G1StringDedup::is_enabled()) {
     G1StringDedup::oops_do(&GenMarkSweep::adjust_pointer_closure);
   }
   GenMarkSweep::adjust_marks();
   G1AdjustPointersClosure blk;
   g1h->heap_region_iterate(&blk);
 }
 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
   // 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 (code and comment not fixed for perm removal), so we tell the validate code
   // to use a higher index (saved from phase2) when verifying perm_gen.
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   GCTraceTime tm("phase 4", G1Log::fine() && Verbose, true, gc_timer());
   GenMarkSweep::trace("4");
   G1SpaceCompactClosure blk;
   g1h->heap_region_iterate(&blk);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1MarkSweep.cpp@595c0f60d50d (annotated)

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