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/shenandoah/brooksPointer.hpp"
26 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shared/space.inline.hpp"
29 #include "memory/universe.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/mutexLocker.hpp"
32 #include "runtime/os.hpp"
33 #include "runtime/safepoint.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, size_t index) {
41
42 reserved = MemRegion(start, regionSizeWords);
43 ContiguousSpace::initialize(reserved, true, false);
44 _live_data = 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::clear_live_data() {
66 assert(Thread::current()->is_VM_thread(), "by VM thread");
67 _live_data = 0;
68 }
69
70 void ShenandoahHeapRegion::set_live_data(size_t s) {
71 assert(Thread::current()->is_VM_thread(), "by VM thread");
72 _live_data = s;
73 }
74
75 size_t ShenandoahHeapRegion::get_live_data() const {
76 assert (sizeof(julong) == sizeof(size_t), "do not read excessively");
77 return (size_t)OrderAccess::load_acquire((volatile julong*)&_live_data);
78 }
79
80 size_t ShenandoahHeapRegion::garbage() const {
81 assert(used() >= get_live_data() || is_humongous(), "Live Data must be a subset of used() live: "SIZE_FORMAT" used: "SIZE_FORMAT,
82 get_live_data(), used());
83 size_t result = used() - get_live_data();
84 return result;
85 }
86
87 bool ShenandoahHeapRegion::is_in_collection_set() const {
88 return _is_in_collection_set;
89 }
90
91 #include <sys/mman.h>
92
93 #ifdef ASSERT
94
95 void ShenandoahHeapRegion::memProtectionOn() {
96 /*
97 log_develop_trace(gc)("Protect memory on region level: "INT32_FORMAT, _mem_protection_level);
98 print(tty);
99 */
100 MutexLockerEx ml(&_mem_protect_lock, true);
101 assert(_mem_protection_level >= 1, "invariant");
102
103 if (--_mem_protection_level == 0) {
104 if (ShenandoahVerifyWritesToFromSpace) {
105 assert(! ShenandoahVerifyReadsToFromSpace, "can't verify from-space reads when verifying from-space writes");
106 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_READ);
107 } else {
108 assert(ShenandoahVerifyReadsToFromSpace, "need to be verifying reads here");
109 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_NONE);
110 }
111 }
112 }
113
114 void ShenandoahHeapRegion::memProtectionOff() {
115 /*
116 tty->print_cr("unprotect memory on region level: "INT32_FORMAT, _mem_protection_level);
117 print(tty);
118 */
119 MutexLockerEx ml(&_mem_protect_lock, true);
120 assert(_mem_protection_level >= 0, "invariant");
121 if (_mem_protection_level++ == 0) {
122 os::protect_memory((char*) bottom(), end() - bottom(), os::MEM_PROT_RW);
123 }
124 }
125
126 #endif
127
128 void ShenandoahHeapRegion::set_is_in_collection_set(bool b) {
129 assert(! (is_humongous() && b), "never ever enter a humongous region into the collection set");
130
131 _is_in_collection_set = b;
132
133 if (b) {
134 // tty->print_cr("registering region in fast-cset");
135 // print();
136 ShenandoahHeap::heap()->register_region_with_in_cset_fast_test(this);
137 }
138
139 #ifdef ASSERT
140 if (ShenandoahVerifyWritesToFromSpace || ShenandoahVerifyReadsToFromSpace) {
141 if (b) {
142 memProtectionOn();
143 assert(_mem_protection_level == 0, "need to be protected here");
144 } else {
145 assert(_mem_protection_level == 0, "need to be protected here");
146 memProtectionOff();
147 }
148 }
149 #endif
150 }
151
152 ByteSize ShenandoahHeapRegion::is_in_collection_set_offset() {
153 return byte_offset_of(ShenandoahHeapRegion, _is_in_collection_set);
154 }
155
156 void ShenandoahHeapRegion::print_on(outputStream* st) const {
157 st->print("ShenandoahHeapRegion: "PTR_FORMAT"/"SIZE_FORMAT, p2i(this), _region_number);
158
159 if (is_in_collection_set())
160 st->print("C");
161 if (is_humongous_start()) {
162 st->print("H");
163 }
164 if (is_humongous_continuation()) {
165 st->print("h");
166 }
167 //else
168 st->print(" ");
169
170 st->print_cr("live = "SIZE_FORMAT" garbage = "SIZE_FORMAT" bottom = "PTR_FORMAT" end = "PTR_FORMAT" top = "PTR_FORMAT,
171 get_live_data(), garbage(), p2i(bottom()), p2i(end()), p2i(top()));
172 }
173
174
175 class SkipUnreachableObjectToOopClosure: public ObjectClosure {
176 ExtendedOopClosure* _cl;
177 bool _skip_unreachable_objects;
178 ShenandoahHeap* _heap;
179
180 public:
181 SkipUnreachableObjectToOopClosure(ExtendedOopClosure* cl, bool skip_unreachable_objects) :
182 _cl(cl), _skip_unreachable_objects(skip_unreachable_objects), _heap(ShenandoahHeap::heap()) {}
183
184 void do_object(oop obj) {
185
186 if ((! _skip_unreachable_objects) || _heap->is_marked_current(obj)) {
187 #ifdef ASSERT
188 if (_skip_unreachable_objects) {
189 assert(_heap->is_marked_current(obj), "obj must be live");
190 }
191 #endif
192 obj->oop_iterate(_cl);
193 }
194
195 }
196 };
197
198 void ShenandoahHeapRegion::object_iterate_interruptible(ObjectClosure* blk, bool allow_cancel) {
199 HeapWord* p = bottom() + BrooksPointer::word_size();
200 ShenandoahHeap* heap = ShenandoahHeap::heap();
201 while (p < top() && !(allow_cancel && heap->cancelled_concgc())) {
202 blk->do_object(oop(p));
203 #ifdef ASSERT
204 if (ShenandoahVerifyReadsToFromSpace) {
205 memProtectionOff();
206 p += oop(p)->size() + BrooksPointer::word_size();
207 memProtectionOn();
208 } else {
209 p += oop(p)->size() + BrooksPointer::word_size();
210 }
211 #else
212 p += oop(p)->size() + BrooksPointer::word_size();
213 #endif
214 }
215 }
216
217 HeapWord* ShenandoahHeapRegion::object_iterate_careful(ObjectClosureCareful* blk) {
218 HeapWord * limit = concurrent_iteration_safe_limit();
219 assert(limit <= top(), "sanity check");
220 for (HeapWord* p = bottom() + BrooksPointer::word_size(); p < limit;) {
221 size_t size = blk->do_object_careful(oop(p));
222 if (size == 0) {
223 return p; // failed at p
224 } else {
225 p += size + BrooksPointer::word_size();
226 }
227 }
228 return NULL; // all done
229 }
230
231 void ShenandoahHeapRegion::oop_iterate_skip_unreachable(ExtendedOopClosure* cl, bool skip_unreachable_objects) {
232 SkipUnreachableObjectToOopClosure cl2(cl, skip_unreachable_objects);
233 object_iterate_interruptible(&cl2, false);
234 }
235
236 void ShenandoahHeapRegion::fill_region() {
237 ShenandoahHeap* sh = (ShenandoahHeap*) Universe::heap();
238
239 if (free() > (BrooksPointer::word_size() + CollectedHeap::min_fill_size())) {
240 HeapWord* filler = allocate(BrooksPointer::word_size());
241 HeapWord* obj = allocate(end() - top());
242 sh->fill_with_object(obj, end() - obj);
243 BrooksPointer::initialize(oop(obj));
244 }
245 }
246
247 void ShenandoahHeapRegion::set_humongous_start(bool start) {
248 _humongous_start = start;
249 }
250
251 void ShenandoahHeapRegion::set_humongous_continuation(bool continuation) {
252 _humongous_continuation = continuation;
253 }
254
255 bool ShenandoahHeapRegion::is_humongous() const {
256 return _humongous_start || _humongous_continuation;
257 }
258
259 bool ShenandoahHeapRegion::is_humongous_start() const {
260 return _humongous_start;
261 }
262
263 bool ShenandoahHeapRegion::is_humongous_continuation() const {
264 return _humongous_continuation;
265 }
266
267 void ShenandoahHeapRegion::do_reset() {
268 ContiguousSpace::initialize(reserved, true, false);
269 clear_live_data();
270 _humongous_start = false;
271 _humongous_continuation = false;
272 // _top_at_mark_start = bottom();
273 _top_at_prev_mark_start = bottom();
274 }
275
276 void ShenandoahHeapRegion::recycle() {
277 do_reset();
278 set_is_in_collection_set(false);
279 }
280
281 void ShenandoahHeapRegion::reset() {
282 assert(_mem_protection_level == 1, "needs to be unprotected here");
283 do_reset();
284 _is_in_collection_set = false;
285 }
286
287 HeapWord* ShenandoahHeapRegion::block_start_const(const void* p) const {
288 assert(MemRegion(bottom(), end()).contains(p),
289 "p ("PTR_FORMAT") not in space ["PTR_FORMAT", "PTR_FORMAT")",
290 p2i(p), p2i(bottom()), p2i(end()));
291 if (p >= top()) {
292 return top();
293 } else {
294 HeapWord* last = bottom() + BrooksPointer::word_size();
295 HeapWord* cur = last;
296 while (cur <= p) {
297 last = cur;
298 cur += oop(cur)->size() + BrooksPointer::word_size();
299 }
300 assert(oop(last)->is_oop(),
301 PTR_FORMAT" should be an object start", p2i(last));
302 return last;
303 }
304 }
305
306 void ShenandoahHeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
307 uintx region_size;
308 if (FLAG_IS_DEFAULT(ShenandoahHeapRegionSize)) {
309 if (ShenandoahMinRegionSize > initial_heap_size / MIN_NUM_REGIONS) {
310 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option");
311 }
312 if (ShenandoahMinRegionSize < MIN_REGION_SIZE) {
313 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option");
314 }
315 if (ShenandoahMaxRegionSize < MIN_REGION_SIZE) {
316 vm_exit_during_initialization("Invalid -XX:ShenandoahMaxRegionSize option");
317 }
318 if (ShenandoahMinRegionSize > ShenandoahMaxRegionSize) {
319 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize or -XX:ShenandoahMaxRegionSize");
320 }
321 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
322 region_size = MAX2(average_heap_size / ShenandoahTargetNumRegions,
323 ShenandoahMinRegionSize);
324
325 // Now make sure that we don't go over or under our limits.
326 region_size = MAX2(ShenandoahMinRegionSize, region_size);
327 region_size = MIN2(ShenandoahMaxRegionSize, region_size);
328
329 } else {
330 if (ShenandoahHeapRegionSize > initial_heap_size / MIN_NUM_REGIONS) {
331 vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option");
332 }
333 if (ShenandoahHeapRegionSize < MIN_REGION_SIZE) {
334 vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option");
335 }
336 region_size = ShenandoahHeapRegionSize;
337 }
338
339 // Make sure region size is at least one large page, if enabled.
340 // Otherwise, mem-protecting one region may falsely protect the adjacent
341 // regions too.
342 if (UseLargePages) {
343 region_size = MAX2(region_size, os::large_page_size());
344 }
345
346 int region_size_log = log2_long((jlong) region_size);
347 // Recalculate the region size to make sure it's a power of
348 // 2. This means that region_size is the largest power of 2 that's
349 // <= what we've calculated so far.
350 region_size = ((uintx)1 << region_size_log);
351
352 // Now, set up the globals.
353 guarantee(RegionSizeShift == 0, "we should only set it once");
354 RegionSizeShift = region_size_log;
355
356 guarantee(RegionSizeBytes == 0, "we should only set it once");
357 RegionSizeBytes = (size_t)region_size;
358
359 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", RegionSizeBytes / M);
360 log_info(gc, init)("Region size in bytes: "SIZE_FORMAT, RegionSizeBytes);
361 log_info(gc, init)("Region size shift: "SIZE_FORMAT, RegionSizeShift);
362 log_info(gc, init)("Initial number of regions: "SIZE_FORMAT, initial_heap_size / RegionSizeBytes);
363 log_info(gc, init)("Maximum number of regions: "SIZE_FORMAT, max_heap_size / RegionSizeBytes);
364 }
365
366 CompactibleSpace* ShenandoahHeapRegion::next_compaction_space() const {
367 return ShenandoahHeap::heap()->next_compaction_region(this);
368 }
369
370 void ShenandoahHeapRegion::prepare_for_compaction(CompactPoint* cp) {
371 scan_and_forward(this, cp);
372 }
373
374 void ShenandoahHeapRegion::adjust_pointers() {
375 // Check first is there is any work to do.
376 if (used() == 0) {
377 return; // Nothing to do.
378 }
379
380 scan_and_adjust_pointers(this);
381 }
382
383 void ShenandoahHeapRegion::compact() {
384 assert(!is_humongous(), "Shouldn't be compacting humongous regions");
385 scan_and_compact(this);
386 }
387
388 void ShenandoahHeapRegion::init_top_at_mark_start() {
389 _top_at_mark_start = top();
390 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), top());
391 }
392
393 void ShenandoahHeapRegion::set_top_at_mark_start(HeapWord* top) {
394 _top_at_mark_start = top;
395 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), top);
396 }
397
398 void ShenandoahHeapRegion::reset_top_at_prev_mark_start() {
399 _top_at_prev_mark_start = bottom();
400 }
401
402 HeapWord* ShenandoahHeapRegion::top_at_mark_start() {
403 return _top_at_mark_start;
404 }
405
406 HeapWord* ShenandoahHeapRegion::top_at_prev_mark_start() {
407 return _top_at_prev_mark_start;
408 }
409
410 HeapWord* ShenandoahHeapRegion::top_prev_mark_bitmap() {
411 return _top_prev_mark_bitmap;
412 }
413
414 bool ShenandoahHeapRegion::allocated_after_prev_mark_start(HeapWord* addr) const {
415 return addr >= _top_at_prev_mark_start;
416 }
417
418 void ShenandoahHeapRegion::swap_top_at_mark_start() {
419 HeapWord* tmp = _top_at_prev_mark_start;
420 _top_at_prev_mark_start = _top_at_mark_start;
421 _top_at_mark_start = tmp;
422 ShenandoahHeap::heap()->set_top_at_mark_start(bottom(), tmp);
423 }
424
425 void ShenandoahHeapRegion::set_top_prev_mark_bitmap(HeapWord* top) {
426 _top_prev_mark_bitmap = top;
427 }
428
429 void ShenandoahHeapRegion::pin() {
430 assert(! SafepointSynchronize::is_at_safepoint(), "only outside safepoints");
431 assert(_critical_pins >= 0, "sanity");
432 Atomic::inc(&_critical_pins);
433 }
434
435 void ShenandoahHeapRegion::unpin() {
436 assert(! SafepointSynchronize::is_at_safepoint(), "only outside safepoints");
437 Atomic::dec(&_critical_pins);
438 assert(_critical_pins >= 0, "sanity");
439 }
440
441 bool ShenandoahHeapRegion::is_pinned() {
442 assert(_critical_pins >= 0, "sanity");
443 assert(SafepointSynchronize::is_at_safepoint(), "only at safepoints");
444 return _critical_pins > 0;
445 }