Mon, 26 Jan 2009 12:47:21 -0800
6786503: Overflow list performance can be improved
Summary: Avoid overflow list walk in CMS & ParNew when it is unnecessary. Fix a couple of correctness issues, including a C-heap leak, in ParNew at the intersection of promotion failure, work queue overflow and object array chunking. Add stress testing option and related assertion checking.
Reviewed-by: jmasa
1 /*
2 * Copyright 2002-2008 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_heapInspection.cpp.incl"
28 // HeapInspection
30 int KlassInfoEntry::compare(KlassInfoEntry* e1, KlassInfoEntry* e2) {
31 if(e1->_instance_words > e2->_instance_words) {
32 return -1;
33 } else if(e1->_instance_words < e2->_instance_words) {
34 return 1;
35 }
36 return 0;
37 }
39 void KlassInfoEntry::print_on(outputStream* st) const {
40 ResourceMark rm;
41 const char* name;;
42 if (_klass->klass_part()->name() != NULL) {
43 name = _klass->klass_part()->external_name();
44 } else {
45 if (_klass == Universe::klassKlassObj()) name = "<klassKlass>"; else
46 if (_klass == Universe::arrayKlassKlassObj()) name = "<arrayKlassKlass>"; else
47 if (_klass == Universe::objArrayKlassKlassObj()) name = "<objArrayKlassKlass>"; else
48 if (_klass == Universe::instanceKlassKlassObj()) name = "<instanceKlassKlass>"; else
49 if (_klass == Universe::typeArrayKlassKlassObj()) name = "<typeArrayKlassKlass>"; else
50 if (_klass == Universe::symbolKlassObj()) name = "<symbolKlass>"; else
51 if (_klass == Universe::boolArrayKlassObj()) name = "<boolArrayKlass>"; else
52 if (_klass == Universe::charArrayKlassObj()) name = "<charArrayKlass>"; else
53 if (_klass == Universe::singleArrayKlassObj()) name = "<singleArrayKlass>"; else
54 if (_klass == Universe::doubleArrayKlassObj()) name = "<doubleArrayKlass>"; else
55 if (_klass == Universe::byteArrayKlassObj()) name = "<byteArrayKlass>"; else
56 if (_klass == Universe::shortArrayKlassObj()) name = "<shortArrayKlass>"; else
57 if (_klass == Universe::intArrayKlassObj()) name = "<intArrayKlass>"; else
58 if (_klass == Universe::longArrayKlassObj()) name = "<longArrayKlass>"; else
59 if (_klass == Universe::methodKlassObj()) name = "<methodKlass>"; else
60 if (_klass == Universe::constMethodKlassObj()) name = "<constMethodKlass>"; else
61 if (_klass == Universe::methodDataKlassObj()) name = "<methodDataKlass>"; else
62 if (_klass == Universe::constantPoolKlassObj()) name = "<constantPoolKlass>"; else
63 if (_klass == Universe::constantPoolCacheKlassObj()) name = "<constantPoolCacheKlass>"; else
64 if (_klass == Universe::compiledICHolderKlassObj()) name = "<compiledICHolderKlass>"; else
65 name = "<no name>";
66 }
67 // simplify the formatting (ILP32 vs LP64) - always cast the numbers to 64-bit
68 st->print_cr(INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13) " %s",
69 (jlong) _instance_count,
70 (julong) _instance_words * HeapWordSize,
71 name);
72 }
74 KlassInfoEntry* KlassInfoBucket::lookup(const klassOop k) {
75 KlassInfoEntry* elt = _list;
76 while (elt != NULL) {
77 if (elt->is_equal(k)) {
78 return elt;
79 }
80 elt = elt->next();
81 }
82 elt = new KlassInfoEntry(k, list());
83 // We may be out of space to allocate the new entry.
84 if (elt != NULL) {
85 set_list(elt);
86 }
87 return elt;
88 }
90 void KlassInfoBucket::iterate(KlassInfoClosure* cic) {
91 KlassInfoEntry* elt = _list;
92 while (elt != NULL) {
93 cic->do_cinfo(elt);
94 elt = elt->next();
95 }
96 }
98 void KlassInfoBucket::empty() {
99 KlassInfoEntry* elt = _list;
100 _list = NULL;
101 while (elt != NULL) {
102 KlassInfoEntry* next = elt->next();
103 delete elt;
104 elt = next;
105 }
106 }
108 KlassInfoTable::KlassInfoTable(int size, HeapWord* ref) {
109 _size = 0;
110 _ref = ref;
111 _buckets = NEW_C_HEAP_ARRAY(KlassInfoBucket, size);
112 if (_buckets != NULL) {
113 _size = size;
114 for (int index = 0; index < _size; index++) {
115 _buckets[index].initialize();
116 }
117 }
118 }
120 KlassInfoTable::~KlassInfoTable() {
121 if (_buckets != NULL) {
122 for (int index = 0; index < _size; index++) {
123 _buckets[index].empty();
124 }
125 FREE_C_HEAP_ARRAY(KlassInfoBucket, _buckets);
126 _size = 0;
127 }
128 }
130 uint KlassInfoTable::hash(klassOop p) {
131 assert(Universe::heap()->is_in_permanent((HeapWord*)p), "all klasses in permgen");
132 return (uint)(((uintptr_t)p - (uintptr_t)_ref) >> 2);
133 }
135 KlassInfoEntry* KlassInfoTable::lookup(const klassOop k) {
136 uint idx = hash(k) % _size;
137 assert(_buckets != NULL, "Allocation failure should have been caught");
138 KlassInfoEntry* e = _buckets[idx].lookup(k);
139 // Lookup may fail if this is a new klass for which we
140 // could not allocate space for an new entry.
141 assert(e == NULL || k == e->klass(), "must be equal");
142 return e;
143 }
145 // Return false if the entry could not be recorded on account
146 // of running out of space required to create a new entry.
147 bool KlassInfoTable::record_instance(const oop obj) {
148 klassOop k = obj->klass();
149 KlassInfoEntry* elt = lookup(k);
150 // elt may be NULL if it's a new klass for which we
151 // could not allocate space for a new entry in the hashtable.
152 if (elt != NULL) {
153 elt->set_count(elt->count() + 1);
154 elt->set_words(elt->words() + obj->size());
155 return true;
156 } else {
157 return false;
158 }
159 }
161 void KlassInfoTable::iterate(KlassInfoClosure* cic) {
162 assert(_size == 0 || _buckets != NULL, "Allocation failure should have been caught");
163 for (int index = 0; index < _size; index++) {
164 _buckets[index].iterate(cic);
165 }
166 }
168 int KlassInfoHisto::sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2) {
169 return (*e1)->compare(*e1,*e2);
170 }
172 KlassInfoHisto::KlassInfoHisto(const char* title, int estimatedCount) :
173 _title(title) {
174 _elements = new (ResourceObj::C_HEAP) GrowableArray<KlassInfoEntry*>(estimatedCount,true);
175 }
177 KlassInfoHisto::~KlassInfoHisto() {
178 delete _elements;
179 }
181 void KlassInfoHisto::add(KlassInfoEntry* cie) {
182 elements()->append(cie);
183 }
185 void KlassInfoHisto::sort() {
186 elements()->sort(KlassInfoHisto::sort_helper);
187 }
189 void KlassInfoHisto::print_elements(outputStream* st) const {
190 // simplify the formatting (ILP32 vs LP64) - store the sum in 64-bit
191 jlong total = 0;
192 julong totalw = 0;
193 for(int i=0; i < elements()->length(); i++) {
194 st->print("%4d: ", i+1);
195 elements()->at(i)->print_on(st);
196 total += elements()->at(i)->count();
197 totalw += elements()->at(i)->words();
198 }
199 st->print_cr("Total " INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13),
200 total, totalw * HeapWordSize);
201 }
203 void KlassInfoHisto::print_on(outputStream* st) const {
204 st->print_cr("%s",title());
205 print_elements(st);
206 }
208 class HistoClosure : public KlassInfoClosure {
209 private:
210 KlassInfoHisto* _cih;
211 public:
212 HistoClosure(KlassInfoHisto* cih) : _cih(cih) {}
214 void do_cinfo(KlassInfoEntry* cie) {
215 _cih->add(cie);
216 }
217 };
219 class RecordInstanceClosure : public ObjectClosure {
220 private:
221 KlassInfoTable* _cit;
222 size_t _missed_count;
223 public:
224 RecordInstanceClosure(KlassInfoTable* cit) :
225 _cit(cit), _missed_count(0) {}
227 void do_object(oop obj) {
228 if (!_cit->record_instance(obj)) {
229 _missed_count++;
230 }
231 }
233 size_t missed_count() { return _missed_count; }
234 };
236 void HeapInspection::heap_inspection(outputStream* st) {
237 ResourceMark rm;
238 HeapWord* ref;
240 CollectedHeap* heap = Universe::heap();
241 bool is_shared_heap = false;
242 switch (heap->kind()) {
243 case CollectedHeap::G1CollectedHeap:
244 case CollectedHeap::GenCollectedHeap: {
245 is_shared_heap = true;
246 SharedHeap* sh = (SharedHeap*)heap;
247 sh->gc_prologue(false /* !full */); // get any necessary locks, etc.
248 ref = sh->perm_gen()->used_region().start();
249 break;
250 }
251 #ifndef SERIALGC
252 case CollectedHeap::ParallelScavengeHeap: {
253 ParallelScavengeHeap* psh = (ParallelScavengeHeap*)heap;
254 ref = psh->perm_gen()->object_space()->used_region().start();
255 break;
256 }
257 #endif // SERIALGC
258 default:
259 ShouldNotReachHere(); // Unexpected heap kind for this op
260 }
261 // Collect klass instance info
262 KlassInfoTable cit(KlassInfoTable::cit_size, ref);
263 if (!cit.allocation_failed()) {
264 // Iterate over objects in the heap
265 RecordInstanceClosure ric(&cit);
266 // If this operation encounters a bad object when using CMS,
267 // consider using safe_object_iterate() which avoids perm gen
268 // objects that may contain bad references.
269 Universe::heap()->object_iterate(&ric);
271 // Report if certain classes are not counted because of
272 // running out of C-heap for the histogram.
273 size_t missed_count = ric.missed_count();
274 if (missed_count != 0) {
275 st->print_cr("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
276 " total instances in data below",
277 missed_count);
278 }
279 // Sort and print klass instance info
280 KlassInfoHisto histo("\n"
281 " num #instances #bytes class name\n"
282 "----------------------------------------------",
283 KlassInfoHisto::histo_initial_size);
284 HistoClosure hc(&histo);
285 cit.iterate(&hc);
286 histo.sort();
287 histo.print_on(st);
288 } else {
289 st->print_cr("WARNING: Ran out of C-heap; histogram not generated");
290 }
291 st->flush();
293 if (is_shared_heap) {
294 SharedHeap* sh = (SharedHeap*)heap;
295 sh->gc_epilogue(false /* !full */); // release all acquired locks, etc.
296 }
297 }
299 class FindInstanceClosure : public ObjectClosure {
300 private:
301 klassOop _klass;
302 GrowableArray<oop>* _result;
304 public:
305 FindInstanceClosure(klassOop k, GrowableArray<oop>* result) : _klass(k), _result(result) {};
307 void do_object(oop obj) {
308 if (obj->is_a(_klass)) {
309 _result->append(obj);
310 }
311 }
312 };
314 void HeapInspection::find_instances_at_safepoint(klassOop k, GrowableArray<oop>* result) {
315 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
316 assert(Heap_lock->is_locked(), "should have the Heap_lock")
318 // Ensure that the heap is parsable
319 Universe::heap()->ensure_parsability(false); // no need to retire TALBs
321 // Iterate over objects in the heap
322 FindInstanceClosure fic(k, result);
323 // If this operation encounters a bad object when using CMS,
324 // consider using safe_object_iterate() which avoids perm gen
325 // objects that may contain bad references.
326 Universe::heap()->object_iterate(&fic);
327 }