author | coleenp |
Sun, 13 Apr 2008 17:43:42 -0400 | |
changeset 360 | 21d113ecbf6a |
parent 1 | 489c9b5090e2 |
child 971 | f0b20be4165d |
child 670 | ddf3e9583f2f |
permissions | -rw-r--r-- |
1 | 1 |
/* |
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* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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* |
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*/ |
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#include "incls/_precompiled.incl" |
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#include "incls/_genMarkSweep.cpp.incl" |
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void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, |
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bool clear_all_softrefs) { |
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assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
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// hook up weak ref data so it can be used during Mark-Sweep |
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assert(ref_processor() == NULL, "no stomping"); |
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_ref_processor = rp; |
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assert(rp != NULL, "should be non-NULL"); |
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TraceTime t1("Full GC", PrintGC && !PrintGCDetails, true, gclog_or_tty); |
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// When collecting the permanent generation methodOops may be moving, |
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// so we either have to flush all bcp data or convert it into bci. |
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CodeCache::gc_prologue(); |
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Threads::gc_prologue(); |
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// Increment the invocation count for the permanent generation, since it is |
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// implicitly collected whenever we do a full mark sweep collection. |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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gch->perm_gen()->stat_record()->invocations++; |
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// Capture heap size before collection for printing. |
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size_t gch_prev_used = gch->used(); |
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// Some of the card table updates below assume that the perm gen is |
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// also being collected. |
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assert(level == gch->n_gens() - 1, |
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"All generations are being collected, ergo perm gen too."); |
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// Capture used regions for each generation that will be |
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// subject to collection, so that card table adjustments can |
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// be made intelligently (see clear / invalidate further below). |
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gch->save_used_regions(level, true /* perm */); |
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allocate_stacks(); |
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mark_sweep_phase1(level, clear_all_softrefs); |
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mark_sweep_phase2(); |
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// Don't add any more derived pointers during phase3 |
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COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); |
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COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); |
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mark_sweep_phase3(level); |
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VALIDATE_MARK_SWEEP_ONLY( |
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if (ValidateMarkSweep) { |
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21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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guarantee(_root_refs_stack->length() == 0, "should be empty by now"); |
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} |
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) |
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mark_sweep_phase4(); |
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VALIDATE_MARK_SWEEP_ONLY( |
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if (ValidateMarkSweep) { |
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guarantee(_live_oops->length() == _live_oops_moved_to->length(), |
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"should be the same size"); |
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} |
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) |
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restore_marks(); |
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// Set saved marks for allocation profiler (and other things? -- dld) |
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// (Should this be in general part?) |
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gch->save_marks(); |
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deallocate_stacks(); |
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// If compaction completely evacuated all generations younger than this |
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// one, then we can clear the card table. Otherwise, we must invalidate |
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// it (consider all cards dirty). In the future, we might consider doing |
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// compaction within generations only, and doing card-table sliding. |
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bool all_empty = true; |
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for (int i = 0; all_empty && i < level; i++) { |
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Generation* g = gch->get_gen(i); |
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all_empty = all_empty && gch->get_gen(i)->used() == 0; |
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} |
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GenRemSet* rs = gch->rem_set(); |
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// Clear/invalidate below make use of the "prev_used_regions" saved earlier. |
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if (all_empty) { |
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// We've evacuated all generations below us. |
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Generation* g = gch->get_gen(level); |
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rs->clear_into_younger(g, true /* perm */); |
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} else { |
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// Invalidate the cards corresponding to the currently used |
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// region and clear those corresponding to the evacuated region |
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// of all generations just collected (i.e. level and younger). |
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rs->invalidate_or_clear(gch->get_gen(level), |
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true /* younger */, |
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true /* perm */); |
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} |
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Threads::gc_epilogue(); |
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CodeCache::gc_epilogue(); |
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if (PrintGC && !PrintGCDetails) { |
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gch->print_heap_change(gch_prev_used); |
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} |
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// refs processing: clean slate |
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_ref_processor = NULL; |
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// Update heap occupancy information which is used as |
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// input to soft ref clearing policy at the next gc. |
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Universe::update_heap_info_at_gc(); |
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// Update time of last gc for all generations we collected |
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// (which curently is all the generations in the heap). |
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gch->update_time_of_last_gc(os::javaTimeMillis()); |
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} |
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void GenMarkSweep::allocate_stacks() { |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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// Scratch request on behalf of oldest generation; will do no |
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// allocation. |
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ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0); |
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// $$$ To cut a corner, we'll only use the first scratch block, and then |
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// revert to malloc. |
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if (scratch != NULL) { |
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_preserved_count_max = |
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scratch->num_words * HeapWordSize / sizeof(PreservedMark); |
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} else { |
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_preserved_count_max = 0; |
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} |
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_preserved_marks = (PreservedMark*)scratch; |
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_preserved_count = 0; |
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_preserved_mark_stack = NULL; |
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_preserved_oop_stack = NULL; |
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_marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); |
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int size = SystemDictionary::number_of_classes() * 2; |
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_revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); |
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#ifdef VALIDATE_MARK_SWEEP |
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if (ValidateMarkSweep) { |
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21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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_root_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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_other_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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_adjusted_pointers = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
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_live_oops = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); |
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_live_oops_moved_to = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); |
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_live_oops_size = new (ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); |
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} |
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if (RecordMarkSweepCompaction) { |
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if (_cur_gc_live_oops == NULL) { |
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_cur_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); |
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_cur_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); |
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_cur_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); |
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_last_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); |
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_last_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); |
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_last_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); |
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} else { |
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_cur_gc_live_oops->clear(); |
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_cur_gc_live_oops_moved_to->clear(); |
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_cur_gc_live_oops_size->clear(); |
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} |
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} |
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#endif |
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} |
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void GenMarkSweep::deallocate_stacks() { |
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if (_preserved_oop_stack) { |
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delete _preserved_mark_stack; |
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_preserved_mark_stack = NULL; |
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delete _preserved_oop_stack; |
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_preserved_oop_stack = NULL; |
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} |
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delete _marking_stack; |
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delete _revisit_klass_stack; |
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#ifdef VALIDATE_MARK_SWEEP |
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if (ValidateMarkSweep) { |
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delete _root_refs_stack; |
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delete _other_refs_stack; |
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delete _adjusted_pointers; |
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delete _live_oops; |
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delete _live_oops_size; |
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delete _live_oops_moved_to; |
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_live_oops_index = 0; |
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_live_oops_index_at_perm = 0; |
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} |
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#endif |
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} |
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void GenMarkSweep::mark_sweep_phase1(int level, |
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bool clear_all_softrefs) { |
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// Recursively traverse all live objects and mark them |
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EventMark m("1 mark object"); |
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TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); |
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trace(" 1"); |
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VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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// Because follow_root_closure is created statically, cannot |
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// use OopsInGenClosure constructor which takes a generation, |
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// as the Universe has not been created when the static constructors |
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// are run. |
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follow_root_closure.set_orig_generation(gch->get_gen(level)); |
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gch->gen_process_strong_roots(level, |
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false, // Younger gens are not roots. |
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true, // Collecting permanent generation. |
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SharedHeap::SO_SystemClasses, |
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&follow_root_closure, &follow_root_closure); |
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// Process reference objects found during marking |
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{ |
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ReferencePolicy *soft_ref_policy; |
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if (clear_all_softrefs) { |
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soft_ref_policy = new AlwaysClearPolicy(); |
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} else { |
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#ifdef COMPILER2 |
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soft_ref_policy = new LRUMaxHeapPolicy(); |
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#else |
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soft_ref_policy = new LRUCurrentHeapPolicy(); |
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#endif // COMPILER2 |
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} |
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assert(soft_ref_policy != NULL,"No soft reference policy"); |
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ref_processor()->process_discovered_references( |
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soft_ref_policy, &is_alive, &keep_alive, |
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&follow_stack_closure, NULL); |
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} |
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// Follow system dictionary roots and unload classes |
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bool purged_class = SystemDictionary::do_unloading(&is_alive); |
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// Follow code cache roots |
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CodeCache::do_unloading(&is_alive, &keep_alive, purged_class); |
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follow_stack(); // Flush marking stack |
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// Update subklass/sibling/implementor links of live klasses |
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follow_weak_klass_links(); |
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assert(_marking_stack->is_empty(), "just drained"); |
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// Visit symbol and interned string tables and delete unmarked oops |
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SymbolTable::unlink(&is_alive); |
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StringTable::unlink(&is_alive); |
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assert(_marking_stack->is_empty(), "stack should be empty by now"); |
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} |
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void GenMarkSweep::mark_sweep_phase2() { |
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// Now all live objects are marked, compute the new object addresses. |
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// It is imperative that we traverse perm_gen LAST. If dead space is |
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// allowed a range of dead object may get overwritten by a dead int |
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// array. If perm_gen is not traversed last a klassOop may get |
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// overwritten. This is fine since it is dead, but if the class has dead |
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// instances we have to skip them, and in order to find their size we |
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// need the klassOop! |
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// |
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// It is not required that we traverse spaces in the same order in |
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// phase2, phase3 and phase4, but the ValidateMarkSweep live oops |
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// tracking expects us to do so. See comment under phase4. |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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Generation* pg = gch->perm_gen(); |
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EventMark m("2 compute new addresses"); |
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TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); |
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trace("2"); |
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VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); |
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gch->prepare_for_compaction(); |
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VALIDATE_MARK_SWEEP_ONLY(_live_oops_index_at_perm = _live_oops_index); |
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CompactPoint perm_cp(pg, NULL, NULL); |
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pg->prepare_for_compaction(&perm_cp); |
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} |
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class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure { |
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public: |
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void do_generation(Generation* gen) { |
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gen->adjust_pointers(); |
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} |
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}; |
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void GenMarkSweep::mark_sweep_phase3(int level) { |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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Generation* pg = gch->perm_gen(); |
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// Adjust the pointers to reflect the new locations |
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EventMark m("3 adjust pointers"); |
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TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); |
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trace("3"); |
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VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); |
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// Needs to be done before the system dictionary is adjusted. |
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pg->pre_adjust_pointers(); |
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// Because the two closures below are created statically, cannot |
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// use OopsInGenClosure constructor which takes a generation, |
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// as the Universe has not been created when the static constructors |
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// are run. |
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adjust_root_pointer_closure.set_orig_generation(gch->get_gen(level)); |
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adjust_pointer_closure.set_orig_generation(gch->get_gen(level)); |
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gch->gen_process_strong_roots(level, |
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false, // Younger gens are not roots. |
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true, // Collecting permanent generation. |
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SharedHeap::SO_AllClasses, |
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&adjust_root_pointer_closure, |
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&adjust_root_pointer_closure); |
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// Now adjust pointers in remaining weak roots. (All of which should |
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// have been cleared if they pointed to non-surviving objects.) |
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gch->gen_process_weak_roots(&adjust_root_pointer_closure, |
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&adjust_pointer_closure); |
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adjust_marks(); |
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GenAdjustPointersClosure blk; |
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gch->generation_iterate(&blk, true); |
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pg->adjust_pointers(); |
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} |
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class GenCompactClosure: public GenCollectedHeap::GenClosure { |
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public: |
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void do_generation(Generation* gen) { |
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gen->compact(); |
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} |
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}; |
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void GenMarkSweep::mark_sweep_phase4() { |
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// All pointers are now adjusted, move objects accordingly |
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// It is imperative that we traverse perm_gen first in phase4. All |
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// classes must be allocated earlier than their instances, and traversing |
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// perm_gen first makes sure that all klassOops have moved to their new |
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// location before any instance does a dispatch through it's klass! |
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// The ValidateMarkSweep live oops tracking expects us to traverse spaces |
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// in the same order in phase2, phase3 and phase4. We don't quite do that |
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// here (perm_gen first rather than last), so we tell the validate code |
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// to use a higher index (saved from phase2) when verifying perm_gen. |
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GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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Generation* pg = gch->perm_gen(); |
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EventMark m("4 compact heap"); |
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TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); |
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trace("4"); |
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VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(true)); |
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380 |
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pg->compact(); |
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382 |
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383 |
VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); |
|
384 |
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385 |
GenCompactClosure blk; |
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gch->generation_iterate(&blk, true); |
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387 |
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VALIDATE_MARK_SWEEP_ONLY(compaction_complete()); |
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389 |
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390 |
pg->post_compact(); // Shared spaces verification. |
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} |