jdk8-mips64-public/hotspot: src/share/vm/memory/genMarkSweep.cpp@1ee8caae33af (annotated)

src/share/vm/memory/genMarkSweep.cpp@1ee8caae33af (annotated)

src/share/vm/memory/genMarkSweep.cpp

Thu, 21 Aug 2008 23:36:31 -0400

author: tonyp
date: Thu, 21 Aug 2008 23:36:31 -0400
changeset 791: 1ee8caae33af
parent 704: 850fdf70db2b
child 888: c96030fff130
permissions: -rw-r--r--

Merge

 /*
  * Copyright 2001-2008 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/_genMarkSweep.cpp.incl"
 void GenMarkSweep::invoke_at_safepoint(int level, 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(ref_processor() == NULL, "no stomping");
   _ref_processor = rp;
   assert(rp != NULL, "should be non-NULL");
   TraceTime t1("Full GC", PrintGC && !PrintGCDetails, true, gclog_or_tty);
   // 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.
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   gch->perm_gen()->stat_record()->invocations++;
   // Capture heap size before collection for printing.
   size_t gch_prev_used = gch->used();
   // Some of the card table updates below assume that the perm gen is
   // also being collected.
   assert(level == gch->n_gens() - 1,
          "All generations are being collected, ergo perm gen too.");
   // Capture used regions for each generation that will be
   // subject to collection, so that card table adjustments can
   // be made intelligently (see clear / invalidate further below).
   gch->save_used_regions(level, true /* perm */);
   allocate_stacks();
   mark_sweep_phase1(level, clear_all_softrefs);
   mark_sweep_phase2();
   // Don't add any more derived pointers during phase3
   COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
   COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
   mark_sweep_phase3(level);
   VALIDATE_MARK_SWEEP_ONLY(
     if (ValidateMarkSweep) {
       guarantee(_root_refs_stack->length() == 0, "should be empty by now");
     }
   )
   mark_sweep_phase4();
   VALIDATE_MARK_SWEEP_ONLY(
     if (ValidateMarkSweep) {
       guarantee(_live_oops->length() == _live_oops_moved_to->length(),
                 "should be the same size");
     }
   )
   restore_marks();
   // Set saved marks for allocation profiler (and other things? -- dld)
   // (Should this be in general part?)
   gch->save_marks();
   deallocate_stacks();
   // If compaction completely evacuated all generations younger than this
   // one, then we can clear the card table.  Otherwise, we must invalidate
   // it (consider all cards dirty).  In the future, we might consider doing
   // compaction within generations only, and doing card-table sliding.
   bool all_empty = true;
   for (int i = 0; all_empty && i < level; i++) {
     Generation* g = gch->get_gen(i);
     all_empty = all_empty && gch->get_gen(i)->used() == 0;
   }
   GenRemSet* rs = gch->rem_set();
   // Clear/invalidate below make use of the "prev_used_regions" saved earlier.
   if (all_empty) {
     // We've evacuated all generations below us.
     Generation* g = gch->get_gen(level);
     rs->clear_into_younger(g, true /* perm */);
   } else {
     // Invalidate the cards corresponding to the currently used
     // region and clear those corresponding to the evacuated region
     // of all generations just collected (i.e. level and younger).
     rs->invalidate_or_clear(gch->get_gen(level),
                             true /* younger */,
                             true /* perm */);
   }
   Threads::gc_epilogue();
   CodeCache::gc_epilogue();
   if (PrintGC && !PrintGCDetails) {
     gch->print_heap_change(gch_prev_used);
   }
   // refs processing: clean slate
   _ref_processor = NULL;
   // Update heap occupancy information which is used as
   // input to soft ref clearing policy at the next gc.
   Universe::update_heap_info_at_gc();
   // Update time of last gc for all generations we collected
   // (which curently is all the generations in the heap).
   gch->update_time_of_last_gc(os::javaTimeMillis());
 }
 void GenMarkSweep::allocate_stacks() {
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   // Scratch request on behalf of oldest generation; will do no
   // allocation.
   ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0);
   // $$$ To cut a corner, we'll only use the first scratch block, and then
   // revert to malloc.
   if (scratch != NULL) {
     _preserved_count_max =
       scratch->num_words * HeapWordSize / sizeof(PreservedMark);
   } else {
     _preserved_count_max = 0;
   }
   _preserved_marks = (PreservedMark*)scratch;
   _preserved_count = 0;
   _preserved_mark_stack = NULL;
   _preserved_oop_stack = NULL;
   _marking_stack       = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
   int size = SystemDictionary::number_of_classes() * 2;
   _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
 #ifdef VALIDATE_MARK_SWEEP
   if (ValidateMarkSweep) {
     _root_refs_stack    = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true);
     _other_refs_stack   = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true);
     _adjusted_pointers  = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true);
     _live_oops          = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true);
     _live_oops_moved_to = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true);
     _live_oops_size     = new (ResourceObj::C_HEAP) GrowableArray<size_t>(100, true);
   }
   if (RecordMarkSweepCompaction) {
     if (_cur_gc_live_oops == NULL) {
       _cur_gc_live_oops           = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true);
       _cur_gc_live_oops_moved_to  = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true);
       _cur_gc_live_oops_size      = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true);
       _last_gc_live_oops          = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true);
       _last_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true);
       _last_gc_live_oops_size     = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true);
     } else {
       _cur_gc_live_oops->clear();
       _cur_gc_live_oops_moved_to->clear();
       _cur_gc_live_oops_size->clear();
     }
   }
 #endif
 }
 void GenMarkSweep::deallocate_stacks() {
   if (!UseG1GC) {
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     gch->release_scratch();
   }
   if (_preserved_oop_stack) {
     delete _preserved_mark_stack;
     _preserved_mark_stack = NULL;
     delete _preserved_oop_stack;
     _preserved_oop_stack = NULL;
   }
   delete _marking_stack;
   delete _revisit_klass_stack;
 #ifdef VALIDATE_MARK_SWEEP
   if (ValidateMarkSweep) {
     delete _root_refs_stack;
     delete _other_refs_stack;
     delete _adjusted_pointers;
     delete _live_oops;
     delete _live_oops_size;
     delete _live_oops_moved_to;
     _live_oops_index = 0;
     _live_oops_index_at_perm = 0;
   }
 #endif
 }
 void GenMarkSweep::mark_sweep_phase1(int level,
                                   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);
   trace(" 1");
   VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false));
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   // Because follow_root_closure is created statically, cannot
   // use OopsInGenClosure constructor which takes a generation,
   // as the Universe has not been created when the static constructors
   // are run.
   follow_root_closure.set_orig_generation(gch->get_gen(level));
   gch->gen_process_strong_roots(level,
                                 false, // Younger gens are not roots.
                                 true,  // Collecting permanent generation.
                                 SharedHeap::SO_SystemClasses,
                                 &follow_root_closure, &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 // COMPILER2
     }
     assert(soft_ref_policy != NULL,"No soft reference policy");
     ref_processor()->process_discovered_references(
       soft_ref_policy, &is_alive, &keep_alive,
       &follow_stack_closure, NULL);
   }
   // Follow system dictionary roots and unload classes
   bool purged_class = SystemDictionary::do_unloading(&is_alive);
   // Follow code cache roots
   CodeCache::do_unloading(&is_alive, &keep_alive, purged_class);
   follow_stack(); // Flush marking stack
   // Update subklass/sibling/implementor links of live klasses
   follow_weak_klass_links();
   assert(_marking_stack->is_empty(), "just drained");
   // Visit symbol and interned string tables and delete unmarked oops
   SymbolTable::unlink(&is_alive);
   StringTable::unlink(&is_alive);
   assert(_marking_stack->is_empty(), "stack should be empty by now");
 }
 void GenMarkSweep::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.
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   Generation* pg = gch->perm_gen();
   EventMark m("2 compute new addresses");
   TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty);
   trace("2");
   VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false));
   gch->prepare_for_compaction();
   VALIDATE_MARK_SWEEP_ONLY(_live_oops_index_at_perm = _live_oops_index);
   CompactPoint perm_cp(pg, NULL, NULL);
   pg->prepare_for_compaction(&perm_cp);
 }
 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure {
 public:
   void do_generation(Generation* gen) {
     gen->adjust_pointers();
   }
 };
 void GenMarkSweep::mark_sweep_phase3(int level) {
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   Generation* pg = gch->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);
   trace("3");
   VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false));
   // Needs to be done before the system dictionary is adjusted.
   pg->pre_adjust_pointers();
   // Because the two closures below are created statically, cannot
   // use OopsInGenClosure constructor which takes a generation,
   // as the Universe has not been created when the static constructors
   // are run.
   adjust_root_pointer_closure.set_orig_generation(gch->get_gen(level));
   adjust_pointer_closure.set_orig_generation(gch->get_gen(level));
   gch->gen_process_strong_roots(level,
                                 false, // Younger gens are not roots.
                                 true,  // Collecting permanent generation.
                                 SharedHeap::SO_AllClasses,
                                 &adjust_root_pointer_closure,
                                 &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.)
   gch->gen_process_weak_roots(&adjust_root_pointer_closure,
                               &adjust_pointer_closure);
   adjust_marks();
   GenAdjustPointersClosure blk;
   gch->generation_iterate(&blk, true);
   pg->adjust_pointers();
 }
 class GenCompactClosure: public GenCollectedHeap::GenClosure {
 public:
   void do_generation(Generation* gen) {
     gen->compact();
   }
 };
 void GenMarkSweep::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.
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   Generation* pg = gch->perm_gen();
   EventMark m("4 compact heap");
   TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty);
   trace("4");
   VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(true));
   pg->compact();
   VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false));
   GenCompactClosure blk;
   gch->generation_iterate(&blk, true);
   VALIDATE_MARK_SWEEP_ONLY(compaction_complete());
   pg->post_compact(); // Shared spaces verification.
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/genMarkSweep.cpp@1ee8caae33af (annotated)

src/share/vm/memory/genMarkSweep.cpp