jdk8-mips64-public/hotspot: comparison src/share/vm/memory/genMarkSweep.cpp

--1:000000000000
+:f90c822e73f8
+/*
+* Copyright (c) 2001, 2013, 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/shared/gcHeapSummary.hpp"
+#include "gc_implementation/shared/gcTimer.hpp"
+#include "gc_implementation/shared/gcTrace.hpp"
+#include "gc_implementation/shared/gcTraceTime.hpp"
+#include "gc_interface/collectedHeap.inline.hpp"
+#include "memory/genCollectedHeap.hpp"
+#include "memory/genMarkSweep.hpp"
+#include "memory/genOopClosures.inline.hpp"
+#include "memory/generation.inline.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/fprofiler.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/synchronizer.hpp"
+#include "runtime/thread.inline.hpp"
+#include "runtime/vmThread.hpp"
+#include "utilities/copy.hpp"
+#include "utilities/events.hpp"
+void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, bool clear_all_softrefs) {
+guarantee(level == 1, "We always collect both old and young.");
+assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
+GenCollectedHeap* gch = GenCollectedHeap::heap();
+#ifdef ASSERT
+if (gch->collector_policy()->should_clear_all_soft_refs()) {
+assert(clear_all_softrefs, "Policy should have been checked earlier");
+}
+#endif
+// hook up weak ref data so it can be used during Mark-Sweep
+assert(ref_processor() == NULL, "no stomping");
+assert(rp != NULL, "should be non-NULL");
+_ref_processor = rp;
+rp->setup_policy(clear_all_softrefs);
+GCTraceTime t1(GCCauseString("Full GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL);
+gch->trace_heap_before_gc(_gc_tracer);
+// 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();
+// Increment the invocation count
+_total_invocations++;
+// Capture heap size before collection for printing.
+size_t gch_prev_used = gch->used();
+// 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);
+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);
+mark_sweep_phase4();
+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();
+Generation* old_gen = gch->get_gen(level);
+// Clear/invalidate below make use of the "prev_used_regions" saved earlier.
+if (all_empty) {
+// We've evacuated all generations below us.
+rs->clear_into_younger(old_gen);
+} else {
+// Invalidate the cards corresponding to the currently used
+// region and clear those corresponding to the evacuated region.
+rs->invalidate_or_clear(old_gen);
+}
+Threads::gc_epilogue();
+CodeCache::gc_epilogue();
+JvmtiExport::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).
+// We need to use a monotonically non-deccreasing time in ms
+// or we will see time-warp warnings and os::javaTimeMillis()
+// does not guarantee monotonicity.
+jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+gch->update_time_of_last_gc(now);
+gch->trace_heap_after_gc(_gc_tracer);
+}
+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;
+}
+void GenMarkSweep::deallocate_stacks() {
+if (!UseG1GC) {
+GenCollectedHeap* gch = GenCollectedHeap::heap();
+gch->release_scratch();
+}
+_preserved_mark_stack.clear(true);
+_preserved_oop_stack.clear(true);
+_marking_stack.clear();
+_objarray_stack.clear(true);
+}
+void GenMarkSweep::mark_sweep_phase1(int level,
+bool clear_all_softrefs) {
+// Recursively traverse all live objects and mark them
+GCTraceTime tm("phase 1", PrintGC && Verbose, true, _gc_timer);
+trace(" 1");
+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));
+// Need new claim bits before marking starts.
+ClassLoaderDataGraph::clear_claimed_marks();
+gch->gen_process_strong_roots(level,
+false, // Younger gens are not roots.
+true,  // activate StrongRootsScope
+false, // not scavenging
+SharedHeap::SO_SystemClasses,
+&follow_root_closure,
+true,   // walk code active on stacks
+&follow_root_closure,
+&follow_klass_closure);
+// Process reference objects found during marking
+{
+ref_processor()->setup_policy(clear_all_softrefs);
+const ReferenceProcessorStats& stats =
+ref_processor()->process_discovered_references(
+&is_alive, &keep_alive, &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(_marking_stack.is_empty(), "Marking should have completed");
+// Unload classes and purge the SystemDictionary.
+bool purged_class = SystemDictionary::do_unloading(&is_alive);
+// Unload nmethods.
+CodeCache::do_unloading(&is_alive, purged_class);
+// Prune dead klasses from subklass/sibling/implementor lists.
+Klass::clean_weak_klass_links(&is_alive);
+// Delete entries for dead interned strings.
+StringTable::unlink(&is_alive);
+// Clean up unreferenced symbols in symbol table.
+SymbolTable::unlink();
+gc_tracer()->report_object_count_after_gc(&is_alive);
+}
+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 Klass* 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 Klass*!
+//
+// 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();
+GCTraceTime tm("phase 2", PrintGC && Verbose, true, _gc_timer);
+trace("2");
+gch->prepare_for_compaction();
+}
+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();
+// Adjust the pointers to reflect the new locations
+GCTraceTime tm("phase 3", PrintGC && Verbose, true, _gc_timer);
+trace("3");
+// Need new claim bits for the pointer adjustment tracing.
+ClassLoaderDataGraph::clear_claimed_marks();
+// Because the closure below is created statically, we cannot
+// use OopsInGenClosure constructor which takes a generation,
+// as the Universe has not been created when the static constructors
+// are run.
+adjust_pointer_closure.set_orig_generation(gch->get_gen(level));
+gch->gen_process_strong_roots(level,
+false, // Younger gens are not roots.
+true,  // activate StrongRootsScope
+false, // not scavenging
+SharedHeap::SO_AllClasses,
+&adjust_pointer_closure,
+false, // do not walk code
+&adjust_pointer_closure,
+&adjust_klass_closure);
+// Now adjust pointers in remaining weak roots.  (All of which should
+// have been cleared if they pointed to non-surviving objects.)
+CodeBlobToOopClosure adjust_code_pointer_closure(&adjust_pointer_closure,
+/*do_marking=*/ false);
+gch->gen_process_weak_roots(&adjust_pointer_closure,
+&adjust_code_pointer_closure);
+adjust_marks();
+GenAdjustPointersClosure blk;
+gch->generation_iterate(&blk, true);
+}
+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 Klass*s 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();
+GCTraceTime tm("phase 4", PrintGC && Verbose, true, _gc_timer);
+trace("4");
+GenCompactClosure blk;
+gch->generation_iterate(&blk, true);
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/memory/genMarkSweep.cpp

src/share/vm/memory/genMarkSweep.cpp