1 /*
2 * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "memory/allocation.hpp"
25 #include "gc/g1/heapRegionBounds.inline.hpp"
26 #include "gc/shenandoah/brooksPointer.hpp"
27 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
29 #include "gc/shared/space.inline.hpp"
30 #include "memory/universe.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/mutexLocker.hpp"
33 #include "runtime/os.hpp"
34 #include "runtime/safepoint.hpp"
35
36 Monitor ShenandoahHeapRegion::_mem_protect_lock(Mutex::special, "ShenandoahMemProtect_lock", true, Monitor::_safepoint_check_never);
37 size_t ShenandoahHeapRegion::RegionSizeShift = 0;
38 size_t ShenandoahHeapRegion::RegionSizeBytes = 0;
39
40 jint ShenandoahHeapRegion::initialize_heap_region(HeapWord* start,
41 size_t regionSizeWords, int index) {
42
43 reserved = MemRegion((HeapWord*) start, regionSizeWords);
44 ContiguousSpace::initialize(reserved, true, false);
45 liveData = 0;
46 _is_in_collection_set = false;
47 _region_number = index;
48 #ifdef ASSERT
49 _mem_protection_level = 1; // Off, level 1.
50 #endif
51 _top_at_mark_start = bottom();
52 _top_at_prev_mark_start = bottom();
53 _top_prev_mark_bitmap = bottom();
54 return JNI_OK;
55 }
56
57 size_t ShenandoahHeapRegion::region_number() const {
58 return _region_number;
59 }
60
61 bool ShenandoahHeapRegion::rollback_allocation(uint size) {
62 set_top(top() - size);
63 return true;
64 }
65
66 void ShenandoahHeapRegion::clearLiveData() {
67 setLiveData(0);
68 }
69
70 void ShenandoahHeapRegion::setLiveData(size_t s) {
71 Atomic::store_ptr(s, (intptr_t*) &liveData);
72 }
73
74 size_t ShenandoahHeapRegion::getLiveData() const {
75 return liveData;
76 }
77
78 size_t ShenandoahHeapRegion::garbage() const {
79 assert(used() >= getLiveData() || is_humongous(), "Live Data must be a subset of used() live: "SIZE_FORMAT" used: "SIZE_FORMAT, getLiveData(), used());
80 size_t result = used() - getLiveData();
81 return result;
82 }
83
84 bool ShenandoahHeapRegion::is_in_collection_set() const {
85 return _is_in_collection_set;
86 }
87
88 #include <sys/mman.h>
89
90 #ifdef ASSERT
91
92 void ShenandoahHeapRegion::memProtectionOn() {
93 /*
94 tty->print_cr("protect memory on region level: "INT32_FORMAT, _mem_protection_level);
95 print(tty);
96 */
97 MutexLockerEx ml(&_mem_protect_lock, true);
98 assert(_mem_protection_level >= 1, "invariant");
99
100 if (--_mem_protection_level == 0) {
101 if (ShenandoahVerifyWritesToFromSpace) {
102 assert(! ShenandoahVerifyReadsToFromSpace, "can't verify from-space reads when verifying from-space writes");
103 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_READ);
104 } else {
105 assert(ShenandoahVerifyReadsToFromSpace, "need to be verifying reads here");
106 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_NONE);
107 }
108 }
109 }
110
111 void ShenandoahHeapRegion::memProtectionOff() {
112 /*
113 tty->print_cr("unprotect memory on region level: "INT32_FORMAT, _mem_protection_level);
114 print(tty);
115 */
116 MutexLockerEx ml(&_mem_protect_lock, true);
117 assert(_mem_protection_level >= 0, "invariant");
118 if (_mem_protection_level++ == 0) {
119 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_RW);
120 }
121 }
122
123 #endif
124
125 void ShenandoahHeapRegion::set_is_in_collection_set(bool b) {
126 assert(! (is_humongous() && b), "never ever enter a humongous region into the collection set");
127
128 _is_in_collection_set = b;
129
130 if (b) {
131 // tty->print_cr("registering region in fast-cset");
132 // print();
133 ShenandoahHeap::heap()->register_region_with_in_cset_fast_test(this);
134 }
135
136 #ifdef ASSERT
137 if (ShenandoahVerifyWritesToFromSpace || ShenandoahVerifyReadsToFromSpace) {
138 if (b) {
139 memProtectionOn();
140 assert(_mem_protection_level == 0, "need to be protected here");
141 } else {
142 assert(_mem_protection_level == 0, "need to be protected here");
143 memProtectionOff();
144 }
145 }
146 #endif
147 }
148
149 ByteSize ShenandoahHeapRegion::is_in_collection_set_offset() {
150 return byte_offset_of(ShenandoahHeapRegion, _is_in_collection_set);
151 }
152
153 void ShenandoahHeapRegion::print_on(outputStream* st) const {
154 st->print_cr("ShenandoahHeapRegion: "PTR_FORMAT"/"SIZE_FORMAT, p2i(this), _region_number);
155
156 if (is_in_collection_set())
157 st->print("C");
158 if (is_humongous_start()) {
159 st->print("H");
160 }
161 if (is_humongous_continuation()) {
162 st->print("h");
163 }
164 //else
165 st->print(" ");
166
167 st->print_cr("live = "SIZE_FORMAT" garbage = "SIZE_FORMAT" bottom = "PTR_FORMAT" end = "PTR_FORMAT" top = "PTR_FORMAT,
168 getLiveData(), garbage(), p2i(bottom()), p2i(end()), p2i(top()));
169 }
170
171
172 class SkipUnreachableObjectToOopClosure: public ObjectClosure {
173 ExtendedOopClosure* _cl;
174 bool _skip_unreachable_objects;
175 ShenandoahHeap* _heap;
176
177 public:
178 SkipUnreachableObjectToOopClosure(ExtendedOopClosure* cl, bool skip_unreachable_objects) :
179 _cl(cl), _skip_unreachable_objects(skip_unreachable_objects), _heap(ShenandoahHeap::heap()) {}
180
181 void do_object(oop obj) {
182
183 if ((! _skip_unreachable_objects) || _heap->is_marked_current(obj)) {
184 #ifdef ASSERT
185 if (_skip_unreachable_objects) {
186 assert(_heap->is_marked_current(obj), "obj must be live");
187 }
188 #endif
189 obj->oop_iterate(_cl);
190 }
191
192 }
193 };
194
195 void ShenandoahHeapRegion::object_iterate_interruptible(ObjectClosure* blk, bool allow_cancel) {
196 HeapWord* p = bottom() + BrooksPointer::word_size();
197 ShenandoahHeap* heap = ShenandoahHeap::heap();
198 while (p < top() && !(allow_cancel && heap->cancelled_concgc())) {
199 blk->do_object(oop(p));
200 #ifdef ASSERT
201 if (ShenandoahVerifyReadsToFromSpace) {
202 memProtectionOff();
203 p += oop(p)->size() + BrooksPointer::word_size();
204 memProtectionOn();
205 } else {
206 p += oop(p)->size() + BrooksPointer::word_size();
207 }
208 #else
209 p += oop(p)->size() + BrooksPointer::word_size();
210 #endif
211 }
212 }
213
214 void ShenandoahHeapRegion::marked_object_iterate(ObjectClosure* blk) {
215 HeapWord* p = bottom();
216 ShenandoahHeap* heap = ShenandoahHeap::heap();
217 CMBitMap* bitmap = heap->next_mark_bit_map();
218 while (p < top()) {
219 p += BrooksPointer::word_size();
220 p = bitmap->getNextMarkedWordAddress(p, top());
221 if (p < top()) {
222 oop obj = oop(p);
223 assert(heap->is_marked_current(obj), "must be marked");
224 assert(p >= bottom() && p < top(), "must be within region bounds");
225 assert(obj->is_oop(), "sanity");
226 size_t size = obj->size();
227 blk->do_object(obj);
228 p += size;
229 }
230 }
231 }
232
233 HeapWord* ShenandoahHeapRegion::object_iterate_careful(ObjectClosureCareful* blk) {
234 HeapWord * limit = concurrent_iteration_safe_limit();
235 assert(limit <= top(), "sanity check");
236 for (HeapWord* p = bottom() + BrooksPointer::word_size(); p < limit;) {
237 size_t size = blk->do_object_careful(oop(p));
238 if (size == 0) {
239 return p; // failed at p
240 } else {
241 p += size + BrooksPointer::word_size();
242 }
243 }
244 return NULL; // all done
245 }
246
247 void ShenandoahHeapRegion::oop_iterate_skip_unreachable(ExtendedOopClosure* cl, bool skip_unreachable_objects) {
248 SkipUnreachableObjectToOopClosure cl2(cl, skip_unreachable_objects);
249 object_iterate_interruptible(&cl2, false);
250 }
251
252 void ShenandoahHeapRegion::fill_region() {
253 ShenandoahHeap* sh = (ShenandoahHeap*) Universe::heap();
254
255 if (free() > (BrooksPointer::word_size() + CollectedHeap::min_fill_size())) {
256 HeapWord* filler = allocate(BrooksPointer::word_size());
257 HeapWord* obj = allocate(end() - top());
258 sh->fill_with_object(obj, end() - obj);
259 sh->initialize_brooks_ptr(oop(obj));
260 }
261 }
262
263 void ShenandoahHeapRegion::set_humongous_start(bool start) {
264 _humongous_start = start;
265 }
266
267 void ShenandoahHeapRegion::set_humongous_continuation(bool continuation) {
268 _humongous_continuation = continuation;
269 }
270
271 bool ShenandoahHeapRegion::is_humongous() const {
272 return _humongous_start || _humongous_continuation;
273 }
274
275 bool ShenandoahHeapRegion::is_humongous_start() const {
276 return _humongous_start;
277 }
278
279 bool ShenandoahHeapRegion::is_humongous_continuation() const {
280 return _humongous_continuation;
281 }
282
283 void ShenandoahHeapRegion::do_reset() {
284 ContiguousSpace::initialize(reserved, true, false);
285 clearLiveData();
286 _humongous_start = false;
287 _humongous_continuation = false;
288 // _top_at_mark_start = bottom();
289 _top_at_prev_mark_start = bottom();
290 }
291
292 void ShenandoahHeapRegion::recycle() {
293 do_reset();
294 set_is_in_collection_set(false);
295 }
296
297 void ShenandoahHeapRegion::reset() {
298 assert(_mem_protection_level == 1, "needs to be unprotected here");
299 do_reset();
300 _is_in_collection_set = false;
301 }
302
303 HeapWord* ShenandoahHeapRegion::block_start_const(const void* p) const {
304 assert(MemRegion(bottom(), end()).contains(p),
305 "p ("PTR_FORMAT") not in space ["PTR_FORMAT", "PTR_FORMAT")",
306 p2i(p), p2i(bottom()), p2i(end()));
307 if (p >= top()) {
308 return top();
309 } else {
310 HeapWord* last = bottom() + BrooksPointer::word_size();
311 HeapWord* cur = last;
312 while (cur <= p) {
313 last = cur;
314 cur += oop(cur)->size() + BrooksPointer::word_size();
315 }
316 assert(oop(last)->is_oop(),
317 PTR_FORMAT" should be an object start", p2i(last));
318 return last;
319 }
320 }
321
322 void ShenandoahHeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
323 uintx region_size = ShenandoahHeapRegionSize;
324 if (FLAG_IS_DEFAULT(ShenandoahHeapRegionSize)) {
325 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
326 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
327 (uintx) HeapRegionBounds::min_size());
328 }
329
330 int region_size_log = log2_long((jlong) region_size);
331 // Recalculate the region size to make sure it's a power of
332 // 2. This means that region_size is the largest power of 2 that's
333 // <= what we've calculated so far.
334 region_size = ((uintx)1 << region_size_log);
335
336 // Now make sure that we don't go over or under our limits.
337 if (region_size < HeapRegionBounds::min_size()) {
338 region_size = HeapRegionBounds::min_size();
339 } else if (region_size > HeapRegionBounds::max_size()) {
340 region_size = HeapRegionBounds::max_size();
341 }
342
343 // And recalculate the log.
344 region_size_log = log2_long((jlong) region_size);
345
346 // Now, set up the globals.
347 guarantee(RegionSizeShift == 0, "we should only set it once");
348 RegionSizeShift = region_size_log;
349
350 guarantee(RegionSizeBytes == 0, "we should only set it once");
351 RegionSizeBytes = (size_t)region_size;
352
353 if (ShenandoahLogConfig) {
354 tty->print_cr("Region size in bytes: "SIZE_FORMAT, RegionSizeBytes);
355 tty->print_cr("Region size shift: "SIZE_FORMAT, RegionSizeShift);
356 tty->print_cr("Initial number of regions: "SIZE_FORMAT, initial_heap_size / RegionSizeBytes);
357 tty->print_cr("Maximum number of regions: "SIZE_FORMAT, max_heap_size / RegionSizeBytes);
358 }
359 }
360
361 CompactibleSpace* ShenandoahHeapRegion::next_compaction_space() const {
362 return ShenandoahHeap::heap()->next_compaction_region(this);
363 }
364
365 void ShenandoahHeapRegion::prepare_for_compaction(CompactPoint* cp) {
366 scan_and_forward(this, cp);
367 }
368
369 void ShenandoahHeapRegion::adjust_pointers() {
370 // Check first is there is any work to do.
371 if (used() == 0) {
372 return; // Nothing to do.
373 }
374
375 scan_and_adjust_pointers(this);
376 }
377
378 void ShenandoahHeapRegion::compact() {
379 assert(!is_humongous(), "Shouldn't be compacting humongous regions");
380 scan_and_compact(this);
381 }
382
383 void ShenandoahHeapRegion::init_top_at_mark_start() {
384 _top_at_mark_start = top();
385 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), top());
386 }
387
388 void ShenandoahHeapRegion::set_top_at_mark_start(HeapWord* top) {
389 _top_at_mark_start = top;
390 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), top);
391 }
392
393 void ShenandoahHeapRegion::reset_top_at_prev_mark_start() {
394 _top_at_prev_mark_start = bottom();
395 }
396
397 HeapWord* ShenandoahHeapRegion::top_at_mark_start() {
398 return _top_at_mark_start;
399 }
400
401 HeapWord* ShenandoahHeapRegion::top_at_prev_mark_start() {
402 return _top_at_prev_mark_start;
403 }
404
405 HeapWord* ShenandoahHeapRegion::top_prev_mark_bitmap() {
406 return _top_prev_mark_bitmap;
407 }
408
409 bool ShenandoahHeapRegion::allocated_after_prev_mark_start(HeapWord* addr) const {
410 return addr >= _top_at_prev_mark_start;
411 }
412
413 void ShenandoahHeapRegion::swap_top_at_mark_start() {
414 HeapWord* tmp = _top_at_prev_mark_start;
415 _top_at_prev_mark_start = _top_at_mark_start;
416 _top_at_mark_start = tmp;
417 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), tmp);
418 }
419
420 void ShenandoahHeapRegion::set_top_prev_mark_bitmap(HeapWord* top) {
421 _top_prev_mark_bitmap = top;
422 }
423
424 void ShenandoahHeapRegion::enter_critical() {
425 assert(! SafepointSynchronize::is_at_safepoint(), "only outside safepoints");
426 assert(_critical_pins >= 0, "sanity");
427 Atomic::inc(&_critical_pins);
428 }
429
430 void ShenandoahHeapRegion::exit_critical() {
431 assert(! SafepointSynchronize::is_at_safepoint(), "only outside safepoints");
432 Atomic::dec(&_critical_pins);
433 assert(_critical_pins >= 0, "sanity");
434 }
435
436 bool ShenandoahHeapRegion::is_pinned() {
437 assert(_critical_pins >= 0, "sanity");
438 assert(SafepointSynchronize::is_at_safepoint(), "only at safepoints");
439 return _critical_pins > 0;
440 }