Mercurial > hg > truffle
annotate src/share/vm/memory/tenuredGeneration.cpp @ 1644:2a47bd84841f
6965184: possible races in make_not_entrant_or_zombie
Reviewed-by: kvn
author | never |
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date | Thu, 08 Jul 2010 14:29:44 -0700 |
parents | c18cbe5936b8 |
children | a7214d79fcf1 |
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0 | 1 /* |
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2 * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_tenuredGeneration.cpp.incl" | |
27 | |
28 TenuredGeneration::TenuredGeneration(ReservedSpace rs, | |
29 size_t initial_byte_size, int level, | |
30 GenRemSet* remset) : | |
31 OneContigSpaceCardGeneration(rs, initial_byte_size, | |
32 MinHeapDeltaBytes, level, remset, NULL) | |
33 { | |
34 HeapWord* bottom = (HeapWord*) _virtual_space.low(); | |
35 HeapWord* end = (HeapWord*) _virtual_space.high(); | |
36 _the_space = new TenuredSpace(_bts, MemRegion(bottom, end)); | |
37 _the_space->reset_saved_mark(); | |
38 _shrink_factor = 0; | |
39 _capacity_at_prologue = 0; | |
40 | |
41 _gc_stats = new GCStats(); | |
42 | |
43 // initialize performance counters | |
44 | |
45 const char* gen_name = "old"; | |
46 | |
47 // Generation Counters -- generation 1, 1 subspace | |
48 _gen_counters = new GenerationCounters(gen_name, 1, 1, &_virtual_space); | |
49 | |
50 _gc_counters = new CollectorCounters("MSC", 1); | |
51 | |
52 _space_counters = new CSpaceCounters(gen_name, 0, | |
53 _virtual_space.reserved_size(), | |
54 _the_space, _gen_counters); | |
55 #ifndef SERIALGC | |
56 if (UseParNewGC && ParallelGCThreads > 0) { | |
57 typedef ParGCAllocBufferWithBOT* ParGCAllocBufferWithBOTPtr; | |
58 _alloc_buffers = NEW_C_HEAP_ARRAY(ParGCAllocBufferWithBOTPtr, | |
59 ParallelGCThreads); | |
60 if (_alloc_buffers == NULL) | |
61 vm_exit_during_initialization("Could not allocate alloc_buffers"); | |
62 for (uint i = 0; i < ParallelGCThreads; i++) { | |
63 _alloc_buffers[i] = | |
64 new ParGCAllocBufferWithBOT(OldPLABSize, _bts); | |
65 if (_alloc_buffers[i] == NULL) | |
66 vm_exit_during_initialization("Could not allocate alloc_buffers"); | |
67 } | |
68 } else { | |
69 _alloc_buffers = NULL; | |
70 } | |
71 #endif // SERIALGC | |
72 } | |
73 | |
74 | |
75 const char* TenuredGeneration::name() const { | |
76 return "tenured generation"; | |
77 } | |
78 | |
79 void TenuredGeneration::compute_new_size() { | |
80 assert(_shrink_factor <= 100, "invalid shrink factor"); | |
81 size_t current_shrink_factor = _shrink_factor; | |
82 _shrink_factor = 0; | |
83 | |
84 // We don't have floating point command-line arguments | |
85 // Note: argument processing ensures that MinHeapFreeRatio < 100. | |
86 const double minimum_free_percentage = MinHeapFreeRatio / 100.0; | |
87 const double maximum_used_percentage = 1.0 - minimum_free_percentage; | |
88 | |
89 // Compute some numbers about the state of the heap. | |
90 const size_t used_after_gc = used(); | |
91 const size_t capacity_after_gc = capacity(); | |
92 | |
93 const double min_tmp = used_after_gc / maximum_used_percentage; | |
94 size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx)); | |
95 // Don't shrink less than the initial generation size | |
96 minimum_desired_capacity = MAX2(minimum_desired_capacity, | |
97 spec()->init_size()); | |
98 assert(used_after_gc <= minimum_desired_capacity, "sanity check"); | |
99 | |
100 if (PrintGC && Verbose) { | |
101 const size_t free_after_gc = free(); | |
102 const double free_percentage = ((double)free_after_gc) / capacity_after_gc; | |
103 gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: "); | |
104 gclog_or_tty->print_cr(" " | |
105 " minimum_free_percentage: %6.2f" | |
106 " maximum_used_percentage: %6.2f", | |
107 minimum_free_percentage, | |
108 maximum_used_percentage); | |
109 gclog_or_tty->print_cr(" " | |
110 " free_after_gc : %6.1fK" | |
111 " used_after_gc : %6.1fK" | |
112 " capacity_after_gc : %6.1fK", | |
113 free_after_gc / (double) K, | |
114 used_after_gc / (double) K, | |
115 capacity_after_gc / (double) K); | |
116 gclog_or_tty->print_cr(" " | |
117 " free_percentage: %6.2f", | |
118 free_percentage); | |
119 } | |
120 | |
121 if (capacity_after_gc < minimum_desired_capacity) { | |
122 // If we have less free space than we want then expand | |
123 size_t expand_bytes = minimum_desired_capacity - capacity_after_gc; | |
124 // Don't expand unless it's significant | |
125 if (expand_bytes >= _min_heap_delta_bytes) { | |
126 expand(expand_bytes, 0); // safe if expansion fails | |
127 } | |
128 if (PrintGC && Verbose) { | |
129 gclog_or_tty->print_cr(" expanding:" | |
130 " minimum_desired_capacity: %6.1fK" | |
131 " expand_bytes: %6.1fK" | |
132 " _min_heap_delta_bytes: %6.1fK", | |
133 minimum_desired_capacity / (double) K, | |
134 expand_bytes / (double) K, | |
135 _min_heap_delta_bytes / (double) K); | |
136 } | |
137 return; | |
138 } | |
139 | |
140 // No expansion, now see if we want to shrink | |
141 size_t shrink_bytes = 0; | |
142 // We would never want to shrink more than this | |
143 size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity; | |
144 | |
145 if (MaxHeapFreeRatio < 100) { | |
146 const double maximum_free_percentage = MaxHeapFreeRatio / 100.0; | |
147 const double minimum_used_percentage = 1.0 - maximum_free_percentage; | |
148 const double max_tmp = used_after_gc / minimum_used_percentage; | |
149 size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx)); | |
150 maximum_desired_capacity = MAX2(maximum_desired_capacity, | |
151 spec()->init_size()); | |
152 if (PrintGC && Verbose) { | |
153 gclog_or_tty->print_cr(" " | |
154 " maximum_free_percentage: %6.2f" | |
155 " minimum_used_percentage: %6.2f", | |
156 maximum_free_percentage, | |
157 minimum_used_percentage); | |
158 gclog_or_tty->print_cr(" " | |
159 " _capacity_at_prologue: %6.1fK" | |
160 " minimum_desired_capacity: %6.1fK" | |
161 " maximum_desired_capacity: %6.1fK", | |
162 _capacity_at_prologue / (double) K, | |
163 minimum_desired_capacity / (double) K, | |
164 maximum_desired_capacity / (double) K); | |
165 } | |
166 assert(minimum_desired_capacity <= maximum_desired_capacity, | |
167 "sanity check"); | |
168 | |
169 if (capacity_after_gc > maximum_desired_capacity) { | |
170 // Capacity too large, compute shrinking size | |
171 shrink_bytes = capacity_after_gc - maximum_desired_capacity; | |
172 // We don't want shrink all the way back to initSize if people call | |
173 // System.gc(), because some programs do that between "phases" and then | |
174 // we'd just have to grow the heap up again for the next phase. So we | |
175 // damp the shrinking: 0% on the first call, 10% on the second call, 40% | |
176 // on the third call, and 100% by the fourth call. But if we recompute | |
177 // size without shrinking, it goes back to 0%. | |
178 shrink_bytes = shrink_bytes / 100 * current_shrink_factor; | |
179 assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); | |
180 if (current_shrink_factor == 0) { | |
181 _shrink_factor = 10; | |
182 } else { | |
183 _shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100); | |
184 } | |
185 if (PrintGC && Verbose) { | |
186 gclog_or_tty->print_cr(" " | |
187 " shrinking:" | |
188 " initSize: %.1fK" | |
189 " maximum_desired_capacity: %.1fK", | |
190 spec()->init_size() / (double) K, | |
191 maximum_desired_capacity / (double) K); | |
192 gclog_or_tty->print_cr(" " | |
193 " shrink_bytes: %.1fK" | |
194 " current_shrink_factor: %d" | |
195 " new shrink factor: %d" | |
196 " _min_heap_delta_bytes: %.1fK", | |
197 shrink_bytes / (double) K, | |
198 current_shrink_factor, | |
199 _shrink_factor, | |
200 _min_heap_delta_bytes / (double) K); | |
201 } | |
202 } | |
203 } | |
204 | |
205 if (capacity_after_gc > _capacity_at_prologue) { | |
206 // We might have expanded for promotions, in which case we might want to | |
207 // take back that expansion if there's room after GC. That keeps us from | |
208 // stretching the heap with promotions when there's plenty of room. | |
209 size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue; | |
210 expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes); | |
211 // We have two shrinking computations, take the largest | |
212 shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion); | |
213 assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); | |
214 if (PrintGC && Verbose) { | |
215 gclog_or_tty->print_cr(" " | |
216 " aggressive shrinking:" | |
217 " _capacity_at_prologue: %.1fK" | |
218 " capacity_after_gc: %.1fK" | |
219 " expansion_for_promotion: %.1fK" | |
220 " shrink_bytes: %.1fK", | |
221 capacity_after_gc / (double) K, | |
222 _capacity_at_prologue / (double) K, | |
223 expansion_for_promotion / (double) K, | |
224 shrink_bytes / (double) K); | |
225 } | |
226 } | |
227 // Don't shrink unless it's significant | |
228 if (shrink_bytes >= _min_heap_delta_bytes) { | |
229 shrink(shrink_bytes); | |
230 } | |
231 assert(used() == used_after_gc && used_after_gc <= capacity(), | |
232 "sanity check"); | |
233 } | |
234 | |
235 void TenuredGeneration::gc_prologue(bool full) { | |
236 _capacity_at_prologue = capacity(); | |
237 _used_at_prologue = used(); | |
238 if (VerifyBeforeGC) { | |
239 verify_alloc_buffers_clean(); | |
240 } | |
241 } | |
242 | |
243 void TenuredGeneration::gc_epilogue(bool full) { | |
244 if (VerifyAfterGC) { | |
245 verify_alloc_buffers_clean(); | |
246 } | |
247 OneContigSpaceCardGeneration::gc_epilogue(full); | |
248 } | |
249 | |
250 | |
251 bool TenuredGeneration::should_collect(bool full, | |
252 size_t size, | |
253 bool is_tlab) { | |
254 // This should be one big conditional or (||), but I want to be able to tell | |
255 // why it returns what it returns (without re-evaluating the conditionals | |
256 // in case they aren't idempotent), so I'm doing it this way. | |
257 // DeMorgan says it's okay. | |
258 bool result = false; | |
259 if (!result && full) { | |
260 result = true; | |
261 if (PrintGC && Verbose) { | |
262 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" | |
263 " full"); | |
264 } | |
265 } | |
266 if (!result && should_allocate(size, is_tlab)) { | |
267 result = true; | |
268 if (PrintGC && Verbose) { | |
269 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" | |
270 " should_allocate(" SIZE_FORMAT ")", | |
271 size); | |
272 } | |
273 } | |
274 // If we don't have very much free space. | |
275 // XXX: 10000 should be a percentage of the capacity!!! | |
276 if (!result && free() < 10000) { | |
277 result = true; | |
278 if (PrintGC && Verbose) { | |
279 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" | |
280 " free(): " SIZE_FORMAT, | |
281 free()); | |
282 } | |
283 } | |
284 // If we had to expand to accomodate promotions from younger generations | |
285 if (!result && _capacity_at_prologue < capacity()) { | |
286 result = true; | |
287 if (PrintGC && Verbose) { | |
288 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" | |
289 "_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT, | |
290 _capacity_at_prologue, capacity()); | |
291 } | |
292 } | |
293 return result; | |
294 } | |
295 | |
296 void TenuredGeneration::collect(bool full, | |
297 bool clear_all_soft_refs, | |
298 size_t size, | |
299 bool is_tlab) { | |
300 retire_alloc_buffers_before_full_gc(); | |
301 OneContigSpaceCardGeneration::collect(full, clear_all_soft_refs, | |
302 size, is_tlab); | |
303 } | |
304 | |
305 void TenuredGeneration::update_gc_stats(int current_level, | |
306 bool full) { | |
307 // If the next lower level(s) has been collected, gather any statistics | |
308 // that are of interest at this point. | |
309 if (!full && (current_level + 1) == level()) { | |
310 // Calculate size of data promoted from the younger generations | |
311 // before doing the collection. | |
312 size_t used_before_gc = used(); | |
313 | |
314 // If the younger gen collections were skipped, then the | |
315 // number of promoted bytes will be 0 and adding it to the | |
316 // average will incorrectly lessen the average. It is, however, | |
317 // also possible that no promotion was needed. | |
318 if (used_before_gc >= _used_at_prologue) { | |
319 size_t promoted_in_bytes = used_before_gc - _used_at_prologue; | |
320 gc_stats()->avg_promoted()->sample(promoted_in_bytes); | |
321 } | |
322 } | |
323 } | |
324 | |
325 void TenuredGeneration::update_counters() { | |
326 if (UsePerfData) { | |
327 _space_counters->update_all(); | |
328 _gen_counters->update_all(); | |
329 } | |
330 } | |
331 | |
332 | |
333 #ifndef SERIALGC | |
334 oop TenuredGeneration::par_promote(int thread_num, | |
335 oop old, markOop m, size_t word_sz) { | |
336 | |
337 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; | |
338 HeapWord* obj_ptr = buf->allocate(word_sz); | |
339 bool is_lab = true; | |
340 if (obj_ptr == NULL) { | |
341 #ifndef PRODUCT | |
342 if (Universe::heap()->promotion_should_fail()) { | |
343 return NULL; | |
344 } | |
345 #endif // #ifndef PRODUCT | |
346 | |
347 // Slow path: | |
348 if (word_sz * 100 < ParallelGCBufferWastePct * buf->word_sz()) { | |
349 // Is small enough; abandon this buffer and start a new one. | |
350 size_t buf_size = buf->word_sz(); | |
351 HeapWord* buf_space = | |
352 TenuredGeneration::par_allocate(buf_size, false); | |
353 if (buf_space == NULL) { | |
354 buf_space = expand_and_allocate(buf_size, false, true /* parallel*/); | |
355 } | |
356 if (buf_space != NULL) { | |
357 buf->retire(false, false); | |
358 buf->set_buf(buf_space); | |
359 obj_ptr = buf->allocate(word_sz); | |
360 assert(obj_ptr != NULL, "Buffer was definitely big enough..."); | |
361 } | |
362 }; | |
363 // Otherwise, buffer allocation failed; try allocating object | |
364 // individually. | |
365 if (obj_ptr == NULL) { | |
366 obj_ptr = TenuredGeneration::par_allocate(word_sz, false); | |
367 if (obj_ptr == NULL) { | |
368 obj_ptr = expand_and_allocate(word_sz, false, true /* parallel */); | |
369 } | |
370 } | |
371 if (obj_ptr == NULL) return NULL; | |
372 } | |
373 assert(obj_ptr != NULL, "program logic"); | |
374 Copy::aligned_disjoint_words((HeapWord*)old, obj_ptr, word_sz); | |
375 oop obj = oop(obj_ptr); | |
376 // Restore the mark word copied above. | |
377 obj->set_mark(m); | |
378 return obj; | |
379 } | |
380 | |
381 void TenuredGeneration::par_promote_alloc_undo(int thread_num, | |
382 HeapWord* obj, | |
383 size_t word_sz) { | |
384 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; | |
385 if (buf->contains(obj)) { | |
386 guarantee(buf->contains(obj + word_sz - 1), | |
387 "should contain whole object"); | |
388 buf->undo_allocation(obj, word_sz); | |
389 } else { | |
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390 CollectedHeap::fill_with_object(obj, word_sz); |
0 | 391 } |
392 } | |
393 | |
394 void TenuredGeneration::par_promote_alloc_done(int thread_num) { | |
395 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; | |
396 buf->retire(true, ParallelGCRetainPLAB); | |
397 } | |
398 | |
399 void TenuredGeneration::retire_alloc_buffers_before_full_gc() { | |
400 if (UseParNewGC) { | |
401 for (uint i = 0; i < ParallelGCThreads; i++) { | |
402 _alloc_buffers[i]->retire(true /*end_of_gc*/, false /*retain*/); | |
403 } | |
404 } | |
405 } | |
406 | |
407 // Verify that any retained parallel allocation buffers do not | |
408 // intersect with dirty cards. | |
409 void TenuredGeneration::verify_alloc_buffers_clean() { | |
410 if (UseParNewGC) { | |
411 for (uint i = 0; i < ParallelGCThreads; i++) { | |
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412 _rs->verify_aligned_region_empty(_alloc_buffers[i]->range()); |
0 | 413 } |
414 } | |
415 } | |
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416 |
0 | 417 #else // SERIALGC |
418 void TenuredGeneration::retire_alloc_buffers_before_full_gc() {} | |
419 void TenuredGeneration::verify_alloc_buffers_clean() {} | |
420 #endif // SERIALGC | |
421 | |
422 bool TenuredGeneration::promotion_attempt_is_safe( | |
423 size_t max_promotion_in_bytes, | |
424 bool younger_handles_promotion_failure) const { | |
425 | |
426 bool result = max_contiguous_available() >= max_promotion_in_bytes; | |
427 | |
428 if (younger_handles_promotion_failure && !result) { | |
429 result = max_contiguous_available() >= | |
430 (size_t) gc_stats()->avg_promoted()->padded_average(); | |
431 if (PrintGC && Verbose && result) { | |
432 gclog_or_tty->print_cr("TenuredGeneration::promotion_attempt_is_safe" | |
433 " contiguous_available: " SIZE_FORMAT | |
434 " avg_promoted: " SIZE_FORMAT, | |
435 max_contiguous_available(), | |
436 gc_stats()->avg_promoted()->padded_average()); | |
437 } | |
438 } else { | |
439 if (PrintGC && Verbose) { | |
440 gclog_or_tty->print_cr("TenuredGeneration::promotion_attempt_is_safe" | |
441 " contiguous_available: " SIZE_FORMAT | |
442 " promotion_in_bytes: " SIZE_FORMAT, | |
443 max_contiguous_available(), max_promotion_in_bytes); | |
444 } | |
445 } | |
446 return result; | |
447 } |