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