1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)psYoungGen.cpp 1.68 07/10/04 10:49:36 JVM"
3 #endif
4 /*
5 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_psYoungGen.cpp.incl"
30
31 PSYoungGen::PSYoungGen(size_t initial_size,
32 size_t min_size,
33 size_t max_size) :
34 _init_gen_size(initial_size),
35 _min_gen_size(min_size),
36 _max_gen_size(max_size)
37 {}
38
39 void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
40 assert(_init_gen_size != 0, "Should have a finite size");
41 _virtual_space = new PSVirtualSpace(rs, alignment);
42 if (!_virtual_space->expand_by(_init_gen_size)) {
43 vm_exit_during_initialization("Could not reserve enough space for "
44 "object heap");
45 }
46 }
47
48 void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
49 initialize_virtual_space(rs, alignment);
50 initialize_work();
51 }
52
53 void PSYoungGen::initialize_work() {
54
55 _reserved = MemRegion((HeapWord*)_virtual_space->low_boundary(),
56 (HeapWord*)_virtual_space->high_boundary());
57
58 MemRegion cmr((HeapWord*)_virtual_space->low(),
59 (HeapWord*)_virtual_space->high());
60 Universe::heap()->barrier_set()->resize_covered_region(cmr);
61
62 if (UseNUMA) {
63 _eden_space = new MutableNUMASpace();
64 } else {
65 _eden_space = new MutableSpace();
66 }
67 _from_space = new MutableSpace();
68 _to_space = new MutableSpace();
69
70 if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
71 vm_exit_during_initialization("Could not allocate a young gen space");
72 }
73
74 // Allocate the mark sweep views of spaces
75 _eden_mark_sweep =
76 new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);
77 _from_mark_sweep =
78 new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);
79 _to_mark_sweep =
80 new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);
81
82 if (_eden_mark_sweep == NULL ||
83 _from_mark_sweep == NULL ||
84 _to_mark_sweep == NULL) {
85 vm_exit_during_initialization("Could not complete allocation"
86 " of the young generation");
87 }
88
89 // Generation Counters - generation 0, 3 subspaces
90 _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);
91
92 // Compute maximum space sizes for performance counters
93 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
94 size_t alignment = heap->intra_generation_alignment();
95 size_t size = _virtual_space->reserved_size();
96
97 size_t max_survivor_size;
98 size_t max_eden_size;
99
100 if (UseAdaptiveSizePolicy) {
101 max_survivor_size = size / MinSurvivorRatio;
102
103 // round the survivor space size down to the nearest alignment
104 // and make sure its size is greater than 0.
105 max_survivor_size = align_size_down(max_survivor_size, alignment);
106 max_survivor_size = MAX2(max_survivor_size, alignment);
107
108 // set the maximum size of eden to be the size of the young gen
109 // less two times the minimum survivor size. The minimum survivor
110 // size for UseAdaptiveSizePolicy is one alignment.
111 max_eden_size = size - 2 * alignment;
112 } else {
113 max_survivor_size = size / InitialSurvivorRatio;
114
115 // round the survivor space size down to the nearest alignment
116 // and make sure its size is greater than 0.
117 max_survivor_size = align_size_down(max_survivor_size, alignment);
118 max_survivor_size = MAX2(max_survivor_size, alignment);
119
120 // set the maximum size of eden to be the size of the young gen
121 // less two times the survivor size when the generation is 100%
122 // committed. The minimum survivor size for -UseAdaptiveSizePolicy
123 // is dependent on the committed portion (current capacity) of the
124 // generation - the less space committed, the smaller the survivor
125 // space, possibly as small as an alignment. However, we are interested
126 // in the case where the young generation is 100% committed, as this
127 // is the point where eden reachs its maximum size. At this point,
128 // the size of a survivor space is max_survivor_size.
129 max_eden_size = size - 2 * max_survivor_size;
130 }
131
132 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
133 _gen_counters);
134 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
135 _gen_counters);
136 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
137 _gen_counters);
138
139 compute_initial_space_boundaries();
140 }
141
142 void PSYoungGen::compute_initial_space_boundaries() {
143 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
144 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
145
146 // Compute sizes
147 size_t alignment = heap->intra_generation_alignment();
148 size_t size = _virtual_space->committed_size();
149
150 size_t survivor_size = size / InitialSurvivorRatio;
151 survivor_size = align_size_down(survivor_size, alignment);
152 // ... but never less than an alignment
153 survivor_size = MAX2(survivor_size, alignment);
154
155 // Young generation is eden + 2 survivor spaces
156 size_t eden_size = size - (2 * survivor_size);
157
158 // Now go ahead and set 'em.
159 set_space_boundaries(eden_size, survivor_size);
160 space_invariants();
161
162 if (UsePerfData) {
163 _eden_counters->update_capacity();
164 _from_counters->update_capacity();
165 _to_counters->update_capacity();
166 }
167 }
168
169 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
170 assert(eden_size < _virtual_space->committed_size(), "just checking");
171 assert(eden_size > 0 && survivor_size > 0, "just checking");
172
173 // Initial layout is Eden, to, from. After swapping survivor spaces,
174 // that leaves us with Eden, from, to, which is step one in our two
175 // step resize-with-live-data procedure.
176 char *eden_start = _virtual_space->low();
177 char *to_start = eden_start + eden_size;
178 char *from_start = to_start + survivor_size;
179 char *from_end = from_start + survivor_size;
180
181 assert(from_end == _virtual_space->high(), "just checking");
182 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
183 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
184 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
185
186 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
187 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
188 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
189
190 eden_space()->initialize(eden_mr, true);
191 to_space()->initialize(to_mr , true);
192 from_space()->initialize(from_mr, true);
193 }
194
195 #ifndef PRODUCT
196 void PSYoungGen::space_invariants() {
197 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
198 const size_t alignment = heap->intra_generation_alignment();
199
200 // Currently, our eden size cannot shrink to zero
201 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
202 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
203 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
204
205 // Relationship of spaces to each other
206 char* eden_start = (char*)eden_space()->bottom();
207 char* eden_end = (char*)eden_space()->end();
208 char* from_start = (char*)from_space()->bottom();
209 char* from_end = (char*)from_space()->end();
210 char* to_start = (char*)to_space()->bottom();
211 char* to_end = (char*)to_space()->end();
212
213 guarantee(eden_start >= _virtual_space->low(), "eden bottom");
214 guarantee(eden_start < eden_end, "eden space consistency");
215 guarantee(from_start < from_end, "from space consistency");
216 guarantee(to_start < to_end, "to space consistency");
217
218 // Check whether from space is below to space
219 if (from_start < to_start) {
220 // Eden, from, to
221 guarantee(eden_end <= from_start, "eden/from boundary");
222 guarantee(from_end <= to_start, "from/to boundary");
223 guarantee(to_end <= _virtual_space->high(), "to end");
224 } else {
225 // Eden, to, from
226 guarantee(eden_end <= to_start, "eden/to boundary");
227 guarantee(to_end <= from_start, "to/from boundary");
228 guarantee(from_end <= _virtual_space->high(), "from end");
229 }
230
231 // More checks that the virtual space is consistent with the spaces
232 assert(_virtual_space->committed_size() >=
233 (eden_space()->capacity_in_bytes() +
234 to_space()->capacity_in_bytes() +
235 from_space()->capacity_in_bytes()), "Committed size is inconsistent");
236 assert(_virtual_space->committed_size() <= _virtual_space->reserved_size(),
237 "Space invariant");
238 char* eden_top = (char*)eden_space()->top();
239 char* from_top = (char*)from_space()->top();
240 char* to_top = (char*)to_space()->top();
241 assert(eden_top <= _virtual_space->high(), "eden top");
242 assert(from_top <= _virtual_space->high(), "from top");
243 assert(to_top <= _virtual_space->high(), "to top");
244
245 _virtual_space->verify();
246 }
247 #endif
248
249 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
250 // Resize the generation if needed. If the generation resize
251 // reports false, do not attempt to resize the spaces.
252 if (resize_generation(eden_size, survivor_size)) {
253 // Then we lay out the spaces inside the generation
254 resize_spaces(eden_size, survivor_size);
255
256 space_invariants();
257
258 if (PrintAdaptiveSizePolicy && Verbose) {
259 gclog_or_tty->print_cr("Young generation size: "
260 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
261 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
262 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
263 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
264 _max_gen_size, min_gen_size());
265 }
266 }
267 }
268
269
270 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
271 const size_t alignment = _virtual_space->alignment();
272 size_t orig_size = _virtual_space->committed_size();
273 bool size_changed = false;
274
275 // There used to be this guarantee there.
276 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
277 // Code below forces this requirement. In addition the desired eden
278 // size and disired survivor sizes are desired goals and may
279 // exceed the total generation size.
280
281 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
282
283 // Adjust new generation size
284 const size_t eden_plus_survivors =
285 align_size_up(eden_size + 2 * survivor_size, alignment);
286 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
287 min_gen_size());
288 assert(desired_size <= max_size(), "just checking");
289
290 if (desired_size > orig_size) {
291 // Grow the generation
292 size_t change = desired_size - orig_size;
293 assert(change % alignment == 0, "just checking");
294 if (!_virtual_space->expand_by(change)) {
295 return false; // Error if we fail to resize!
296 }
297
298 size_changed = true;
299 } else if (desired_size < orig_size) {
300 size_t desired_change = orig_size - desired_size;
301 assert(desired_change % alignment == 0, "just checking");
302
303 desired_change = limit_gen_shrink(desired_change);
304
305 if (desired_change > 0) {
306 virtual_space()->shrink_by(desired_change);
307 reset_survivors_after_shrink();
308
309 size_changed = true;
310 }
311 } else {
312 if (Verbose && PrintGC) {
313 if (orig_size == gen_size_limit()) {
314 gclog_or_tty->print_cr("PSYoung generation size at maximum: "
315 SIZE_FORMAT "K", orig_size/K);
316 } else if (orig_size == min_gen_size()) {
317 gclog_or_tty->print_cr("PSYoung generation size at minium: "
318 SIZE_FORMAT "K", orig_size/K);
319 }
320 }
321 }
322
323 if (size_changed) {
324 post_resize();
325
326 if (Verbose && PrintGC) {
327 size_t current_size = _virtual_space->committed_size();
328 gclog_or_tty->print_cr("PSYoung generation size changed: "
329 SIZE_FORMAT "K->" SIZE_FORMAT "K",
330 orig_size/K, current_size/K);
331 }
332 }
333
334 guarantee(eden_plus_survivors <= _virtual_space->committed_size() ||
335 _virtual_space->committed_size() == max_size(), "Sanity");
336
337 return true;
338 }
339
340
341 void PSYoungGen::resize_spaces(size_t requested_eden_size,
342 size_t requested_survivor_size) {
343 assert(UseAdaptiveSizePolicy, "sanity check");
344 assert(requested_eden_size > 0 && requested_survivor_size > 0,
345 "just checking");
346
347 // We require eden and to space to be empty
348 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
349 return;
350 }
351
352 if (PrintAdaptiveSizePolicy && Verbose) {
353 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
354 SIZE_FORMAT
355 ", requested_survivor_size: " SIZE_FORMAT ")",
356 requested_eden_size, requested_survivor_size);
357 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
358 SIZE_FORMAT,
359 eden_space()->bottom(),
360 eden_space()->end(),
361 pointer_delta(eden_space()->end(),
362 eden_space()->bottom(),
363 sizeof(char)));
364 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") "
365 SIZE_FORMAT,
366 from_space()->bottom(),
367 from_space()->end(),
368 pointer_delta(from_space()->end(),
369 from_space()->bottom(),
370 sizeof(char)));
371 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") "
372 SIZE_FORMAT,
373 to_space()->bottom(),
374 to_space()->end(),
375 pointer_delta( to_space()->end(),
376 to_space()->bottom(),
377 sizeof(char)));
378 }
379
380 // There's nothing to do if the new sizes are the same as the current
381 if (requested_survivor_size == to_space()->capacity_in_bytes() &&
382 requested_survivor_size == from_space()->capacity_in_bytes() &&
383 requested_eden_size == eden_space()->capacity_in_bytes()) {
384 if (PrintAdaptiveSizePolicy && Verbose) {
385 gclog_or_tty->print_cr(" capacities are the right sizes, returning");
386 }
387 return;
388 }
389
390 char* eden_start = (char*)eden_space()->bottom();
391 char* eden_end = (char*)eden_space()->end();
392 char* from_start = (char*)from_space()->bottom();
393 char* from_end = (char*)from_space()->end();
394 char* to_start = (char*)to_space()->bottom();
395 char* to_end = (char*)to_space()->end();
396
397 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
398 const size_t alignment = heap->intra_generation_alignment();
399 const bool maintain_minimum =
400 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
401
402 // Check whether from space is below to space
403 if (from_start < to_start) {
404 // Eden, from, to
405 if (PrintAdaptiveSizePolicy && Verbose) {
406 gclog_or_tty->print_cr(" Eden, from, to:");
407 }
408
409 // Set eden
410 // "requested_eden_size" is a goal for the size of eden
411 // and may not be attainable. "eden_size" below is
412 // calculated based on the location of from-space and
413 // the goal for the size of eden. from-space is
414 // fixed in place because it contains live data.
415 // The calculation is done this way to avoid 32bit
416 // overflow (i.e., eden_start + requested_eden_size
417 // may too large for representation in 32bits).
418 size_t eden_size;
419 if (maintain_minimum) {
420 // Only make eden larger than the requested size if
421 // the minimum size of the generation has to be maintained.
422 // This could be done in general but policy at a higher
423 // level is determining a requested size for eden and that
424 // should be honored unless there is a fundamental reason.
425 eden_size = pointer_delta(from_start,
426 eden_start,
427 sizeof(char));
428 } else {
429 eden_size = MIN2(requested_eden_size,
430 pointer_delta(from_start, eden_start, sizeof(char)));
431 }
432
433 eden_end = eden_start + eden_size;
434 assert(eden_end >= eden_start, "addition overflowed")
435
436 // To may resize into from space as long as it is clear of live data.
437 // From space must remain page aligned, though, so we need to do some
438 // extra calculations.
439
440 // First calculate an optimal to-space
441 to_end = (char*)_virtual_space->high();
442 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
443 sizeof(char));
444
445 // Does the optimal to-space overlap from-space?
446 if (to_start < (char*)from_space()->end()) {
447 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
448
449 // Calculate the minimum offset possible for from_end
450 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));
451
452 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
453 if (from_size == 0) {
454 from_size = alignment;
455 } else {
456 from_size = align_size_up(from_size, alignment);
457 }
458
459 from_end = from_start + from_size;
460 assert(from_end > from_start, "addition overflow or from_size problem");
461
462 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");
463
464 // Now update to_start with the new from_end
465 to_start = MAX2(from_end, to_start);
466 }
467
468 guarantee(to_start != to_end, "to space is zero sized");
469
470 if (PrintAdaptiveSizePolicy && Verbose) {
471 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
472 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
473 eden_start,
474 eden_end,
475 pointer_delta(eden_end, eden_start, sizeof(char)));
476 gclog_or_tty->print_cr(" [from_start .. from_end): "
477 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
478 from_start,
479 from_end,
480 pointer_delta(from_end, from_start, sizeof(char)));
481 gclog_or_tty->print_cr(" [ to_start .. to_end): "
482 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
483 to_start,
484 to_end,
485 pointer_delta( to_end, to_start, sizeof(char)));
486 }
487 } else {
488 // Eden, to, from
489 if (PrintAdaptiveSizePolicy && Verbose) {
490 gclog_or_tty->print_cr(" Eden, to, from:");
491 }
492
493 // To space gets priority over eden resizing. Note that we position
494 // to space as if we were able to resize from space, even though from
495 // space is not modified.
496 // Giving eden priority was tried and gave poorer performance.
497 to_end = (char*)pointer_delta(_virtual_space->high(),
498 (char*)requested_survivor_size,
499 sizeof(char));
500 to_end = MIN2(to_end, from_start);
501 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
502 sizeof(char));
503 // if the space sizes are to be increased by several times then
504 // 'to_start' will point beyond the young generation. In this case
505 // 'to_start' should be adjusted.
506 to_start = MAX2(to_start, eden_start + alignment);
507
508 // Compute how big eden can be, then adjust end.
509 // See comments above on calculating eden_end.
510 size_t eden_size;
511 if (maintain_minimum) {
512 eden_size = pointer_delta(to_start, eden_start, sizeof(char));
513 } else {
514 eden_size = MIN2(requested_eden_size,
515 pointer_delta(to_start, eden_start, sizeof(char)));
516 }
517 eden_end = eden_start + eden_size;
518 assert(eden_end >= eden_start, "addition overflowed")
519
520 // Could choose to not let eden shrink
521 // to_start = MAX2(to_start, eden_end);
522
523 // Don't let eden shrink down to 0 or less.
524 eden_end = MAX2(eden_end, eden_start + alignment);
525 to_start = MAX2(to_start, eden_end);
526
527 if (PrintAdaptiveSizePolicy && Verbose) {
528 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
529 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
530 eden_start,
531 eden_end,
532 pointer_delta(eden_end, eden_start, sizeof(char)));
533 gclog_or_tty->print_cr(" [ to_start .. to_end): "
534 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
535 to_start,
536 to_end,
537 pointer_delta( to_end, to_start, sizeof(char)));
538 gclog_or_tty->print_cr(" [from_start .. from_end): "
539 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
540 from_start,
541 from_end,
542 pointer_delta(from_end, from_start, sizeof(char)));
543 }
544 }
545
546
547 guarantee((HeapWord*)from_start <= from_space()->bottom(),
548 "from start moved to the right");
549 guarantee((HeapWord*)from_end >= from_space()->top(),
550 "from end moved into live data");
551 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
552 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
553 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
554
555 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
556 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
557 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
558
559 // Let's make sure the call to initialize doesn't reset "top"!
560 HeapWord* old_from_top = from_space()->top();
561
562 // For PrintAdaptiveSizePolicy block below
563 size_t old_from = from_space()->capacity_in_bytes();
564 size_t old_to = to_space()->capacity_in_bytes();
565
566 eden_space()->initialize(edenMR, true);
567 to_space()->initialize(toMR , true);
568 from_space()->initialize(fromMR, false); // Note, not cleared!
569
570 assert(from_space()->top() == old_from_top, "from top changed!");
571
572 if (PrintAdaptiveSizePolicy) {
573 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
574 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
575
576 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
577 "collection: %d "
578 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
579 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
580 heap->total_collections(),
581 old_from, old_to,
582 from_space()->capacity_in_bytes(),
583 to_space()->capacity_in_bytes());
584 gclog_or_tty->cr();
585 }
586 }
587
588 void PSYoungGen::swap_spaces() {
589 MutableSpace* s = from_space();
590 _from_space = to_space();
591 _to_space = s;
592
593 // Now update the decorators.
594 PSMarkSweepDecorator* md = from_mark_sweep();
595 _from_mark_sweep = to_mark_sweep();
596 _to_mark_sweep = md;
597
598 assert(from_mark_sweep()->space() == from_space(), "Sanity");
599 assert(to_mark_sweep()->space() == to_space(), "Sanity");
600 }
601
602 size_t PSYoungGen::capacity_in_bytes() const {
603 return eden_space()->capacity_in_bytes()
604 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
605 }
606
607
608 size_t PSYoungGen::used_in_bytes() const {
609 return eden_space()->used_in_bytes()
610 + from_space()->used_in_bytes(); // to_space() is only used during scavenge
611 }
612
613
614 size_t PSYoungGen::free_in_bytes() const {
615 return eden_space()->free_in_bytes()
616 + from_space()->free_in_bytes(); // to_space() is only used during scavenge
617 }
618
619 size_t PSYoungGen::capacity_in_words() const {
620 return eden_space()->capacity_in_words()
621 + from_space()->capacity_in_words(); // to_space() is only used during scavenge
622 }
623
624
625 size_t PSYoungGen::used_in_words() const {
626 return eden_space()->used_in_words()
627 + from_space()->used_in_words(); // to_space() is only used during scavenge
628 }
629
630
631 size_t PSYoungGen::free_in_words() const {
632 return eden_space()->free_in_words()
633 + from_space()->free_in_words(); // to_space() is only used during scavenge
634 }
635
636 void PSYoungGen::object_iterate(ObjectClosure* blk) {
637 eden_space()->object_iterate(blk);
638 from_space()->object_iterate(blk);
639 to_space()->object_iterate(blk);
640 }
641
642 void PSYoungGen::precompact() {
643 eden_mark_sweep()->precompact();
644 from_mark_sweep()->precompact();
645 to_mark_sweep()->precompact();
646 }
647
648 void PSYoungGen::adjust_pointers() {
649 eden_mark_sweep()->adjust_pointers();
650 from_mark_sweep()->adjust_pointers();
651 to_mark_sweep()->adjust_pointers();
652 }
653
654 void PSYoungGen::compact() {
655 eden_mark_sweep()->compact(ZapUnusedHeapArea);
656 from_mark_sweep()->compact(ZapUnusedHeapArea);
657 // Mark sweep stores preserved markOops in to space, don't disturb!
658 to_mark_sweep()->compact(false);
659 }
660
661 void PSYoungGen::move_and_update(ParCompactionManager* cm) {
662 PSParallelCompact::move_and_update(cm, PSParallelCompact::eden_space_id);
663 PSParallelCompact::move_and_update(cm, PSParallelCompact::from_space_id);
664 PSParallelCompact::move_and_update(cm, PSParallelCompact::to_space_id);
665 }
666
667 void PSYoungGen::print() const { print_on(tty); }
668 void PSYoungGen::print_on(outputStream* st) const {
669 st->print(" %-15s", "PSYoungGen");
670 if (PrintGCDetails && Verbose) {
671 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
672 capacity_in_bytes(), used_in_bytes());
673 } else {
674 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
675 capacity_in_bytes()/K, used_in_bytes()/K);
676 }
677 _virtual_space->print_space_boundaries_on(st);
678 st->print(" eden"); eden_space()->print_on(st);
679 st->print(" from"); from_space()->print_on(st);
680 st->print(" to "); to_space()->print_on(st);
681 }
682
683 void PSYoungGen::print_used_change(size_t prev_used) const {
684 gclog_or_tty->print(" [%s:", name());
685 gclog_or_tty->print(" " SIZE_FORMAT "K"
686 "->" SIZE_FORMAT "K"
687 "(" SIZE_FORMAT "K)",
688 prev_used / K, used_in_bytes() / K,
689 capacity_in_bytes() / K);
690 gclog_or_tty->print("]");
691 }
692
693 size_t PSYoungGen::available_for_expansion() {
694 ShouldNotReachHere();
695 return 0;
696 }
697
698 size_t PSYoungGen::available_for_contraction() {
699 ShouldNotReachHere();
700 return 0;
701 }
702
703 size_t PSYoungGen::available_to_min_gen() {
704 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
705 return virtual_space()->committed_size() - min_gen_size();
706 }
707
708 // This method assumes that from-space has live data and that
709 // any shrinkage of the young gen is limited by location of
710 // from-space.
711 size_t PSYoungGen::available_to_live() {
712 size_t delta_in_survivor = 0;
713 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
714 const size_t space_alignment = heap->intra_generation_alignment();
715 const size_t gen_alignment = heap->young_gen_alignment();
716
717 MutableSpace* space_shrinking = NULL;
718 if (from_space()->end() > to_space()->end()) {
719 space_shrinking = from_space();
720 } else {
721 space_shrinking = to_space();
722 }
723
724 // Include any space that is committed but not included in
725 // the survivor spaces.
726 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
727 "Survivor space beyond high end");
728 size_t unused_committed = pointer_delta(virtual_space()->high(),
729 space_shrinking->end(), sizeof(char));
730
731 if (space_shrinking->is_empty()) {
732 // Don't let the space shrink to 0
733 assert(space_shrinking->capacity_in_bytes() >= space_alignment,
734 "Space is too small");
735 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
736 } else {
737 delta_in_survivor = pointer_delta(space_shrinking->end(),
738 space_shrinking->top(),
739 sizeof(char));
740 }
741
742 size_t delta_in_bytes = unused_committed + delta_in_survivor;
743 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
744 return delta_in_bytes;
745 }
746
747 // Return the number of bytes available for resizing down the young
748 // generation. This is the minimum of
749 // input "bytes"
750 // bytes to the minimum young gen size
751 // bytes to the size currently being used + some small extra
752 size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
753 // Allow shrinkage into the current eden but keep eden large enough
754 // to maintain the minimum young gen size
755 bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
756 return align_size_down(bytes, virtual_space()->alignment());
757 }
758
759 void PSYoungGen::reset_after_change() {
760 ShouldNotReachHere();
761 }
762
763 void PSYoungGen::reset_survivors_after_shrink() {
764 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
765 (HeapWord*)virtual_space()->high_boundary());
766 PSScavenge::reference_processor()->set_span(_reserved);
767
768 MutableSpace* space_shrinking = NULL;
769 if (from_space()->end() > to_space()->end()) {
770 space_shrinking = from_space();
771 } else {
772 space_shrinking = to_space();
773 }
774
775 HeapWord* new_end = (HeapWord*)virtual_space()->high();
776 assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
777 // Was there a shrink of the survivor space?
778 if (new_end < space_shrinking->end()) {
779 MemRegion mr(space_shrinking->bottom(), new_end);
780 space_shrinking->initialize(mr, false /* clear */);
781 }
782 }
783
784 // This method currently does not expect to expand into eden (i.e.,
785 // the virtual space boundaries is expected to be consistent
786 // with the eden boundaries..
787 void PSYoungGen::post_resize() {
788 assert_locked_or_safepoint(Heap_lock);
789 assert((eden_space()->bottom() < to_space()->bottom()) &&
790 (eden_space()->bottom() < from_space()->bottom()),
791 "Eden is assumed to be below the survivor spaces");
792
793 MemRegion cmr((HeapWord*)virtual_space()->low(),
794 (HeapWord*)virtual_space()->high());
795 Universe::heap()->barrier_set()->resize_covered_region(cmr);
796 space_invariants();
797 }
798
799
800
801 void PSYoungGen::update_counters() {
802 if (UsePerfData) {
803 _eden_counters->update_all();
804 _from_counters->update_all();
805 _to_counters->update_all();
806 _gen_counters->update_all();
807 }
808 }
809
810 void PSYoungGen::verify(bool allow_dirty) {
811 eden_space()->verify(allow_dirty);
812 from_space()->verify(allow_dirty);
813 to_space()->verify(allow_dirty);
814 }