Mercurial > hg > graal-jvmci-8
view src/share/vm/memory/heapInspection.cpp @ 452:00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes
author | ysr |
---|---|
date | Thu, 20 Nov 2008 12:27:41 -0800 |
parents | 1ee8caae33af |
children | e9be0e04635a |
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/* * Copyright 2002-2008 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/_heapInspection.cpp.incl" // HeapInspection int KlassInfoEntry::compare(KlassInfoEntry* e1, KlassInfoEntry* e2) { if(e1->_instance_words > e2->_instance_words) { return -1; } else if(e1->_instance_words < e2->_instance_words) { return 1; } return 0; } void KlassInfoEntry::print_on(outputStream* st) const { ResourceMark rm; const char* name;; if (_klass->klass_part()->name() != NULL) { name = _klass->klass_part()->external_name(); } else { if (_klass == Universe::klassKlassObj()) name = "<klassKlass>"; else if (_klass == Universe::arrayKlassKlassObj()) name = "<arrayKlassKlass>"; else if (_klass == Universe::objArrayKlassKlassObj()) name = "<objArrayKlassKlass>"; else if (_klass == Universe::instanceKlassKlassObj()) name = "<instanceKlassKlass>"; else if (_klass == Universe::typeArrayKlassKlassObj()) name = "<typeArrayKlassKlass>"; else if (_klass == Universe::symbolKlassObj()) name = "<symbolKlass>"; else if (_klass == Universe::boolArrayKlassObj()) name = "<boolArrayKlass>"; else if (_klass == Universe::charArrayKlassObj()) name = "<charArrayKlass>"; else if (_klass == Universe::singleArrayKlassObj()) name = "<singleArrayKlass>"; else if (_klass == Universe::doubleArrayKlassObj()) name = "<doubleArrayKlass>"; else if (_klass == Universe::byteArrayKlassObj()) name = "<byteArrayKlass>"; else if (_klass == Universe::shortArrayKlassObj()) name = "<shortArrayKlass>"; else if (_klass == Universe::intArrayKlassObj()) name = "<intArrayKlass>"; else if (_klass == Universe::longArrayKlassObj()) name = "<longArrayKlass>"; else if (_klass == Universe::methodKlassObj()) name = "<methodKlass>"; else if (_klass == Universe::constMethodKlassObj()) name = "<constMethodKlass>"; else if (_klass == Universe::methodDataKlassObj()) name = "<methodDataKlass>"; else if (_klass == Universe::constantPoolKlassObj()) name = "<constantPoolKlass>"; else if (_klass == Universe::constantPoolCacheKlassObj()) name = "<constantPoolCacheKlass>"; else if (_klass == Universe::compiledICHolderKlassObj()) name = "<compiledICHolderKlass>"; else name = "<no name>"; } // simplify the formatting (ILP32 vs LP64) - always cast the numbers to 64-bit st->print_cr(INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13) " %s", (jlong) _instance_count, (julong) _instance_words * HeapWordSize, name); } KlassInfoEntry* KlassInfoBucket::lookup(const klassOop k) { KlassInfoEntry* elt = _list; while (elt != NULL) { if (elt->is_equal(k)) { return elt; } elt = elt->next(); } elt = new KlassInfoEntry(k, list()); // We may be out of space to allocate the new entry. if (elt != NULL) { set_list(elt); } return elt; } void KlassInfoBucket::iterate(KlassInfoClosure* cic) { KlassInfoEntry* elt = _list; while (elt != NULL) { cic->do_cinfo(elt); elt = elt->next(); } } void KlassInfoBucket::empty() { KlassInfoEntry* elt = _list; _list = NULL; while (elt != NULL) { KlassInfoEntry* next = elt->next(); delete elt; elt = next; } } KlassInfoTable::KlassInfoTable(int size, HeapWord* ref) { _size = 0; _ref = ref; _buckets = NEW_C_HEAP_ARRAY(KlassInfoBucket, size); if (_buckets != NULL) { _size = size; for (int index = 0; index < _size; index++) { _buckets[index].initialize(); } } } KlassInfoTable::~KlassInfoTable() { if (_buckets != NULL) { for (int index = 0; index < _size; index++) { _buckets[index].empty(); } FREE_C_HEAP_ARRAY(KlassInfoBucket, _buckets); _size = 0; } } uint KlassInfoTable::hash(klassOop p) { assert(Universe::heap()->is_in_permanent((HeapWord*)p), "all klasses in permgen"); return (uint)(((uintptr_t)p - (uintptr_t)_ref) >> 2); } KlassInfoEntry* KlassInfoTable::lookup(const klassOop k) { uint idx = hash(k) % _size; assert(_buckets != NULL, "Allocation failure should have been caught"); KlassInfoEntry* e = _buckets[idx].lookup(k); // Lookup may fail if this is a new klass for which we // could not allocate space for an new entry. assert(e == NULL || k == e->klass(), "must be equal"); return e; } // Return false if the entry could not be recorded on account // of running out of space required to create a new entry. bool KlassInfoTable::record_instance(const oop obj) { klassOop k = obj->klass(); KlassInfoEntry* elt = lookup(k); // elt may be NULL if it's a new klass for which we // could not allocate space for a new entry in the hashtable. if (elt != NULL) { elt->set_count(elt->count() + 1); elt->set_words(elt->words() + obj->size()); return true; } else { return false; } } void KlassInfoTable::iterate(KlassInfoClosure* cic) { assert(_size == 0 || _buckets != NULL, "Allocation failure should have been caught"); for (int index = 0; index < _size; index++) { _buckets[index].iterate(cic); } } int KlassInfoHisto::sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2) { return (*e1)->compare(*e1,*e2); } KlassInfoHisto::KlassInfoHisto(const char* title, int estimatedCount) : _title(title) { _elements = new (ResourceObj::C_HEAP) GrowableArray<KlassInfoEntry*>(estimatedCount,true); } KlassInfoHisto::~KlassInfoHisto() { delete _elements; } void KlassInfoHisto::add(KlassInfoEntry* cie) { elements()->append(cie); } void KlassInfoHisto::sort() { elements()->sort(KlassInfoHisto::sort_helper); } void KlassInfoHisto::print_elements(outputStream* st) const { // simplify the formatting (ILP32 vs LP64) - store the sum in 64-bit jlong total = 0; julong totalw = 0; for(int i=0; i < elements()->length(); i++) { st->print("%4d: ", i+1); elements()->at(i)->print_on(st); total += elements()->at(i)->count(); totalw += elements()->at(i)->words(); } st->print_cr("Total " INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13), total, totalw * HeapWordSize); } void KlassInfoHisto::print_on(outputStream* st) const { st->print_cr("%s",title()); print_elements(st); } class HistoClosure : public KlassInfoClosure { private: KlassInfoHisto* _cih; public: HistoClosure(KlassInfoHisto* cih) : _cih(cih) {} void do_cinfo(KlassInfoEntry* cie) { _cih->add(cie); } }; class RecordInstanceClosure : public ObjectClosure { private: KlassInfoTable* _cit; size_t _missed_count; public: RecordInstanceClosure(KlassInfoTable* cit) : _cit(cit), _missed_count(0) {} void do_object(oop obj) { if (!_cit->record_instance(obj)) { _missed_count++; } } size_t missed_count() { return _missed_count; } }; void HeapInspection::heap_inspection(outputStream* st) { ResourceMark rm; HeapWord* ref; CollectedHeap* heap = Universe::heap(); bool is_shared_heap = false; switch (heap->kind()) { case CollectedHeap::G1CollectedHeap: case CollectedHeap::GenCollectedHeap: { is_shared_heap = true; SharedHeap* sh = (SharedHeap*)heap; sh->gc_prologue(false /* !full */); // get any necessary locks, etc. ref = sh->perm_gen()->used_region().start(); break; } #ifndef SERIALGC case CollectedHeap::ParallelScavengeHeap: { ParallelScavengeHeap* psh = (ParallelScavengeHeap*)heap; ref = psh->perm_gen()->object_space()->used_region().start(); break; } #endif // SERIALGC default: ShouldNotReachHere(); // Unexpected heap kind for this op } // Collect klass instance info KlassInfoTable cit(KlassInfoTable::cit_size, ref); if (!cit.allocation_failed()) { // Iterate over objects in the heap RecordInstanceClosure ric(&cit); Universe::heap()->object_iterate(&ric); // Report if certain classes are not counted because of // running out of C-heap for the histogram. size_t missed_count = ric.missed_count(); if (missed_count != 0) { st->print_cr("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT " total instances in data below", missed_count); } // Sort and print klass instance info KlassInfoHisto histo("\n" " num #instances #bytes class name\n" "----------------------------------------------", KlassInfoHisto::histo_initial_size); HistoClosure hc(&histo); cit.iterate(&hc); histo.sort(); histo.print_on(st); } else { st->print_cr("WARNING: Ran out of C-heap; histogram not generated"); } st->flush(); if (is_shared_heap) { SharedHeap* sh = (SharedHeap*)heap; sh->gc_epilogue(false /* !full */); // release all acquired locks, etc. } } class FindInstanceClosure : public ObjectClosure { private: klassOop _klass; GrowableArray<oop>* _result; public: FindInstanceClosure(klassOop k, GrowableArray<oop>* result) : _klass(k), _result(result) {}; void do_object(oop obj) { if (obj->is_a(_klass)) { _result->append(obj); } } }; void HeapInspection::find_instances_at_safepoint(klassOop k, GrowableArray<oop>* result) { assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); assert(Heap_lock->is_locked(), "should have the Heap_lock") // Ensure that the heap is parsable Universe::heap()->ensure_parsability(false); // no need to retire TALBs // Iterate over objects in the heap FindInstanceClosure fic(k, result); Universe::heap()->object_iterate(&fic); }