Sun, 13 Apr 2008 17:43:42 -0400
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold
1 /*
2 * Copyright 2000-2007 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/_sharedHeap.cpp.incl"
28 SharedHeap* SharedHeap::_sh;
30 // The set of potentially parallel tasks in strong root scanning.
31 enum SH_process_strong_roots_tasks {
32 SH_PS_Universe_oops_do,
33 SH_PS_JNIHandles_oops_do,
34 SH_PS_ObjectSynchronizer_oops_do,
35 SH_PS_FlatProfiler_oops_do,
36 SH_PS_Management_oops_do,
37 SH_PS_SystemDictionary_oops_do,
38 SH_PS_jvmti_oops_do,
39 SH_PS_vmSymbols_oops_do,
40 SH_PS_SymbolTable_oops_do,
41 SH_PS_StringTable_oops_do,
42 SH_PS_CodeCache_oops_do,
43 // Leave this one last.
44 SH_PS_NumElements
45 };
47 SharedHeap::SharedHeap(CollectorPolicy* policy_) :
48 CollectedHeap(),
49 _collector_policy(policy_),
50 _perm_gen(NULL), _rem_set(NULL),
51 _strong_roots_parity(0),
52 _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
53 _workers(NULL), _n_par_threads(0)
54 {
55 if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
56 vm_exit_during_initialization("Failed necessary allocation.");
57 }
58 _sh = this; // ch is static, should be set only once.
59 if ((UseParNewGC ||
60 (UseConcMarkSweepGC && CMSParallelRemarkEnabled)) &&
61 ParallelGCThreads > 0) {
62 _workers = new WorkGang("Parallel GC Threads", ParallelGCThreads, true);
63 if (_workers == NULL) {
64 vm_exit_during_initialization("Failed necessary allocation.");
65 }
66 }
67 }
70 void SharedHeap::set_par_threads(int t) {
71 _n_par_threads = t;
72 _process_strong_tasks->set_par_threads(t);
73 }
75 class AssertIsPermClosure: public OopClosure {
76 public:
77 virtual void do_oop(oop* p) {
78 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
79 }
80 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
81 };
82 static AssertIsPermClosure assert_is_perm_closure;
84 void SharedHeap::change_strong_roots_parity() {
85 // Also set the new collection parity.
86 assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
87 "Not in range.");
88 _strong_roots_parity++;
89 if (_strong_roots_parity == 3) _strong_roots_parity = 1;
90 assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
91 "Not in range.");
92 }
94 void SharedHeap::process_strong_roots(bool collecting_perm_gen,
95 ScanningOption so,
96 OopClosure* roots,
97 OopsInGenClosure* perm_blk) {
98 // General strong roots.
99 if (n_par_threads() == 0) change_strong_roots_parity();
100 if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
101 Universe::oops_do(roots);
102 ReferenceProcessor::oops_do(roots);
103 // Consider perm-gen discovered lists to be strong.
104 perm_gen()->ref_processor()->weak_oops_do(roots);
105 }
106 // Global (strong) JNI handles
107 if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
108 JNIHandles::oops_do(roots);
109 // All threads execute this; the individual threads are task groups.
110 if (ParallelGCThreads > 0) {
111 Threads::possibly_parallel_oops_do(roots);
112 } else {
113 Threads::oops_do(roots);
114 }
115 if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
116 ObjectSynchronizer::oops_do(roots);
117 if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
118 FlatProfiler::oops_do(roots);
119 if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
120 Management::oops_do(roots);
121 if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
122 JvmtiExport::oops_do(roots);
124 if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
125 if (so & SO_AllClasses) {
126 SystemDictionary::oops_do(roots);
127 } else
128 if (so & SO_SystemClasses) {
129 SystemDictionary::always_strong_oops_do(roots);
130 }
131 }
133 if (!_process_strong_tasks->is_task_claimed(SH_PS_SymbolTable_oops_do)) {
134 if (so & SO_Symbols) {
135 SymbolTable::oops_do(roots);
136 }
137 // Verify if the symbol table contents are in the perm gen
138 NOT_PRODUCT(SymbolTable::oops_do(&assert_is_perm_closure));
139 }
141 if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) {
142 if (so & SO_Strings) {
143 StringTable::oops_do(roots);
144 }
145 // Verify if the string table contents are in the perm gen
146 NOT_PRODUCT(StringTable::oops_do(&assert_is_perm_closure));
147 }
149 if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
150 if (so & SO_CodeCache) {
151 CodeCache::oops_do(roots);
152 }
153 // Verify if the code cache contents are in the perm gen
154 NOT_PRODUCT(CodeCache::oops_do(&assert_is_perm_closure));
155 }
157 // Roots that should point only into permanent generation.
158 {
159 OopClosure* blk = NULL;
160 if (collecting_perm_gen) {
161 blk = roots;
162 } else {
163 debug_only(blk = &assert_is_perm_closure);
164 }
165 if (blk != NULL) {
166 if (!_process_strong_tasks->is_task_claimed(SH_PS_vmSymbols_oops_do))
167 vmSymbols::oops_do(blk);
168 }
169 }
171 if (!collecting_perm_gen) {
172 // All threads perform this; coordination is handled internally.
174 rem_set()->younger_refs_iterate(perm_gen(), perm_blk);
175 }
176 _process_strong_tasks->all_tasks_completed();
177 }
179 class AlwaysTrueClosure: public BoolObjectClosure {
180 public:
181 void do_object(oop p) { ShouldNotReachHere(); }
182 bool do_object_b(oop p) { return true; }
183 };
184 static AlwaysTrueClosure always_true;
186 class SkipAdjustingSharedStrings: public OopClosure {
187 OopClosure* _clo;
188 public:
189 SkipAdjustingSharedStrings(OopClosure* clo) : _clo(clo) {}
191 virtual void do_oop(oop* p) {
192 oop o = (*p);
193 if (!o->is_shared_readwrite()) {
194 _clo->do_oop(p);
195 }
196 }
197 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
198 };
200 // Unmarked shared Strings in the StringTable (which got there due to
201 // being in the constant pools of as-yet unloaded shared classes) were
202 // not marked and therefore did not have their mark words preserved.
203 // These entries are also deliberately not purged from the string
204 // table during unloading of unmarked strings. If an identity hash
205 // code was computed for any of these objects, it will not have been
206 // cleared to zero during the forwarding process or by the
207 // RecursiveAdjustSharedObjectClosure, and will be confused by the
208 // adjusting process as a forwarding pointer. We need to skip
209 // forwarding StringTable entries which contain unmarked shared
210 // Strings. Actually, since shared strings won't be moving, we can
211 // just skip adjusting any shared entries in the string table.
213 void SharedHeap::process_weak_roots(OopClosure* root_closure,
214 OopClosure* non_root_closure) {
215 // Global (weak) JNI handles
216 JNIHandles::weak_oops_do(&always_true, root_closure);
218 CodeCache::oops_do(non_root_closure);
219 SymbolTable::oops_do(root_closure);
220 if (UseSharedSpaces && !DumpSharedSpaces) {
221 SkipAdjustingSharedStrings skip_closure(root_closure);
222 StringTable::oops_do(&skip_closure);
223 } else {
224 StringTable::oops_do(root_closure);
225 }
226 }
228 void SharedHeap::set_barrier_set(BarrierSet* bs) {
229 _barrier_set = bs;
230 // Cached barrier set for fast access in oops
231 oopDesc::set_bs(bs);
232 }
234 void SharedHeap::post_initialize() {
235 ref_processing_init();
236 }
238 void SharedHeap::ref_processing_init() {
239 perm_gen()->ref_processor_init();
240 }
242 void SharedHeap::fill_region_with_object(MemRegion mr) {
243 // Disable the posting of JVMTI VMObjectAlloc events as we
244 // don't want the filling of tlabs with filler arrays to be
245 // reported to the profiler.
246 NoJvmtiVMObjectAllocMark njm;
248 // Disable low memory detector because there is no real allocation.
249 LowMemoryDetectorDisabler lmd_dis;
251 // It turns out that post_allocation_setup_array takes a handle, so the
252 // call below contains an implicit conversion. Best to free that handle
253 // as soon as possible.
254 HandleMark hm;
256 size_t word_size = mr.word_size();
257 size_t aligned_array_header_size =
258 align_object_size(typeArrayOopDesc::header_size(T_INT));
260 if (word_size >= aligned_array_header_size) {
261 const size_t array_length =
262 pointer_delta(mr.end(), mr.start()) -
263 typeArrayOopDesc::header_size(T_INT);
264 const size_t array_length_words =
265 array_length * (HeapWordSize/sizeof(jint));
266 post_allocation_setup_array(Universe::intArrayKlassObj(),
267 mr.start(),
268 mr.word_size(),
269 (int)array_length_words);
270 #ifdef ASSERT
271 HeapWord* elt_words = (mr.start() + typeArrayOopDesc::header_size(T_INT));
272 Copy::fill_to_words(elt_words, array_length, 0xDEAFBABE);
273 #endif
274 } else {
275 assert(word_size == (size_t)oopDesc::header_size(), "Unaligned?");
276 post_allocation_setup_obj(SystemDictionary::object_klass(),
277 mr.start(),
278 mr.word_size());
279 }
280 }
282 // Some utilities.
283 void SharedHeap::print_size_transition(size_t bytes_before,
284 size_t bytes_after,
285 size_t capacity) {
286 tty->print(" %d%s->%d%s(%d%s)",
287 byte_size_in_proper_unit(bytes_before),
288 proper_unit_for_byte_size(bytes_before),
289 byte_size_in_proper_unit(bytes_after),
290 proper_unit_for_byte_size(bytes_after),
291 byte_size_in_proper_unit(capacity),
292 proper_unit_for_byte_size(capacity));
293 }