1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved.
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 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_psYoungGen.cpp.incl"
27
28 PSYoungGen::PSYoungGen(size_t initial_size,
29 size_t min_size,
30 size_t max_size) :
31 _init_gen_size(initial_size),
32 _min_gen_size(min_size),
33 _max_gen_size(max_size)
34 {}
35
36 void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
37 assert(_init_gen_size != 0, "Should have a finite size");
38 _virtual_space = new PSVirtualSpace(rs, alignment);
39 if (!virtual_space()->expand_by(_init_gen_size)) {
40 vm_exit_during_initialization("Could not reserve enough space for "
41 "object heap");
42 }
43 }
44
45 void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
46 initialize_virtual_space(rs, alignment);
47 initialize_work();
48 }
49
50 void PSYoungGen::initialize_work() {
51
52 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
53 (HeapWord*)virtual_space()->high_boundary());
54
55 MemRegion cmr((HeapWord*)virtual_space()->low(),
56 (HeapWord*)virtual_space()->high());
57 Universe::heap()->barrier_set()->resize_covered_region(cmr);
58
59 if (ZapUnusedHeapArea) {
60 // Mangle newly committed space immediately because it
61 // can be done here more simply that after the new
62 // spaces have been computed.
63 SpaceMangler::mangle_region(cmr);
64 }
65
66 if (UseNUMA) {
67 _eden_space = new MutableNUMASpace(virtual_space()->alignment());
68 } else {
69 _eden_space = new MutableSpace(virtual_space()->alignment());
70 }
71 _from_space = new MutableSpace(virtual_space()->alignment());
72 _to_space = new MutableSpace(virtual_space()->alignment());
73
74 if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
75 vm_exit_during_initialization("Could not allocate a young gen space");
76 }
77
78 // Allocate the mark sweep views of spaces
79 _eden_mark_sweep =
80 new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);
81 _from_mark_sweep =
82 new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);
83 _to_mark_sweep =
84 new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);
85
86 if (_eden_mark_sweep == NULL ||
87 _from_mark_sweep == NULL ||
88 _to_mark_sweep == NULL) {
89 vm_exit_during_initialization("Could not complete allocation"
90 " of the young generation");
91 }
92
93 // Generation Counters - generation 0, 3 subspaces
94 _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);
95
96 // Compute maximum space sizes for performance counters
97 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
98 size_t alignment = heap->intra_heap_alignment();
99 size_t size = virtual_space()->reserved_size();
100
101 size_t max_survivor_size;
102 size_t max_eden_size;
103
104 if (UseAdaptiveSizePolicy) {
105 max_survivor_size = size / MinSurvivorRatio;
106
107 // round the survivor space size down to the nearest alignment
108 // and make sure its size is greater than 0.
109 max_survivor_size = align_size_down(max_survivor_size, alignment);
110 max_survivor_size = MAX2(max_survivor_size, alignment);
111
112 // set the maximum size of eden to be the size of the young gen
113 // less two times the minimum survivor size. The minimum survivor
114 // size for UseAdaptiveSizePolicy is one alignment.
115 max_eden_size = size - 2 * alignment;
116 } else {
117 max_survivor_size = size / InitialSurvivorRatio;
118
119 // round the survivor space size down to the nearest alignment
120 // and make sure its size is greater than 0.
121 max_survivor_size = align_size_down(max_survivor_size, alignment);
122 max_survivor_size = MAX2(max_survivor_size, alignment);
123
124 // set the maximum size of eden to be the size of the young gen
125 // less two times the survivor size when the generation is 100%
126 // committed. The minimum survivor size for -UseAdaptiveSizePolicy
127 // is dependent on the committed portion (current capacity) of the
128 // generation - the less space committed, the smaller the survivor
129 // space, possibly as small as an alignment. However, we are interested
130 // in the case where the young generation is 100% committed, as this
131 // is the point where eden reachs its maximum size. At this point,
132 // the size of a survivor space is max_survivor_size.
133 max_eden_size = size - 2 * max_survivor_size;
134 }
135
136 _max_eden_size = max_eden_size;
137 _max_survivor_size = max_survivor_size;
138
139 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
140 _gen_counters);
141 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
142 _gen_counters);
143 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
144 _gen_counters);
145
146 compute_initial_space_boundaries();
147 }
148
149 void PSYoungGen::compute_initial_space_boundaries() {
150 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
151 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
152
153 // Compute sizes
154 size_t alignment = heap->intra_heap_alignment();
155 size_t size = virtual_space()->committed_size();
156
157 size_t survivor_size = size / InitialSurvivorRatio;
158 survivor_size = align_size_down(survivor_size, alignment);
159 // ... but never less than an alignment
160 survivor_size = MAX2(survivor_size, alignment);
161
162 // Young generation is eden + 2 survivor spaces
163 size_t eden_size = size - (2 * survivor_size);
164
165 // Now go ahead and set 'em.
166 set_space_boundaries(eden_size, survivor_size);
167 space_invariants();
168
169 _init_survivor_size = survivor_size;
170 _init_eden_size = eden_size;
171
172 if (UsePerfData) {
173 _eden_counters->update_capacity();
174 _from_counters->update_capacity();
175 _to_counters->update_capacity();
176 }
177 }
178
179 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
180 assert(eden_size < virtual_space()->committed_size(), "just checking");
181 assert(eden_size > 0 && survivor_size > 0, "just checking");
182
183 // Initial layout is Eden, to, from. After swapping survivor spaces,
184 // that leaves us with Eden, from, to, which is step one in our two
185 // step resize-with-live-data procedure.
186 char *eden_start = virtual_space()->low();
187 char *to_start = eden_start + eden_size;
188 char *from_start = to_start + survivor_size;
189 char *from_end = from_start + survivor_size;
190
191 assert(from_end == virtual_space()->high(), "just checking");
192 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
193 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
194 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
195
196 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
197 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
198 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
199
200 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
201 to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
202 from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
203 }
204
205 #ifndef PRODUCT
206 void PSYoungGen::space_invariants() {
207 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
208 const size_t alignment = heap->intra_heap_alignment();
209
210 // Currently, our eden size cannot shrink to zero
211 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
212 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
213 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
214
215 // Relationship of spaces to each other
216 char* eden_start = (char*)eden_space()->bottom();
217 char* eden_end = (char*)eden_space()->end();
218 char* from_start = (char*)from_space()->bottom();
219 char* from_end = (char*)from_space()->end();
220 char* to_start = (char*)to_space()->bottom();
221 char* to_end = (char*)to_space()->end();
222
223 guarantee(eden_start >= virtual_space()->low(), "eden bottom");
224 guarantee(eden_start < eden_end, "eden space consistency");
225 guarantee(from_start < from_end, "from space consistency");
226 guarantee(to_start < to_end, "to space consistency");
227
228 // Check whether from space is below to space
229 if (from_start < to_start) {
230 // Eden, from, to
231 guarantee(eden_end <= from_start, "eden/from boundary");
232 guarantee(from_end <= to_start, "from/to boundary");
233 guarantee(to_end <= virtual_space()->high(), "to end");
234 } else {
235 // Eden, to, from
236 guarantee(eden_end <= to_start, "eden/to boundary");
237 guarantee(to_end <= from_start, "to/from boundary");
238 guarantee(from_end <= virtual_space()->high(), "from end");
239 }
240
241 // More checks that the virtual space is consistent with the spaces
242 assert(virtual_space()->committed_size() >=
243 (eden_space()->capacity_in_bytes() +
244 to_space()->capacity_in_bytes() +
245 from_space()->capacity_in_bytes()), "Committed size is inconsistent");
246 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
247 "Space invariant");
248 char* eden_top = (char*)eden_space()->top();
249 char* from_top = (char*)from_space()->top();
250 char* to_top = (char*)to_space()->top();
251 assert(eden_top <= virtual_space()->high(), "eden top");
252 assert(from_top <= virtual_space()->high(), "from top");
253 assert(to_top <= virtual_space()->high(), "to top");
254
255 virtual_space()->verify();
256 }
257 #endif
258
259 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
260 // Resize the generation if needed. If the generation resize
261 // reports false, do not attempt to resize the spaces.
262 if (resize_generation(eden_size, survivor_size)) {
263 // Then we lay out the spaces inside the generation
264 resize_spaces(eden_size, survivor_size);
265
266 space_invariants();
267
268 if (PrintAdaptiveSizePolicy && Verbose) {
269 gclog_or_tty->print_cr("Young generation size: "
270 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
271 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
272 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
273 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
274 _max_gen_size, min_gen_size());
275 }
276 }
277 }
278
279
280 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
281 const size_t alignment = virtual_space()->alignment();
282 size_t orig_size = virtual_space()->committed_size();
283 bool size_changed = false;
284
285 // There used to be this guarantee there.
286 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
287 // Code below forces this requirement. In addition the desired eden
288 // size and disired survivor sizes are desired goals and may
289 // exceed the total generation size.
290
291 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
292
293 // Adjust new generation size
294 const size_t eden_plus_survivors =
295 align_size_up(eden_size + 2 * survivor_size, alignment);
296 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
297 min_gen_size());
298 assert(desired_size <= max_size(), "just checking");
299
300 if (desired_size > orig_size) {
301 // Grow the generation
302 size_t change = desired_size - orig_size;
303 assert(change % alignment == 0, "just checking");
304 HeapWord* prev_high = (HeapWord*) virtual_space()->high();
305 if (!virtual_space()->expand_by(change)) {
306 return false; // Error if we fail to resize!
307 }
308 if (ZapUnusedHeapArea) {
309 // Mangle newly committed space immediately because it
310 // can be done here more simply that after the new
311 // spaces have been computed.
312 HeapWord* new_high = (HeapWord*) virtual_space()->high();
313 MemRegion mangle_region(prev_high, new_high);
314 SpaceMangler::mangle_region(mangle_region);
315 }
316 size_changed = true;
317 } else if (desired_size < orig_size) {
318 size_t desired_change = orig_size - desired_size;
319 assert(desired_change % alignment == 0, "just checking");
320
321 desired_change = limit_gen_shrink(desired_change);
322
323 if (desired_change > 0) {
324 virtual_space()->shrink_by(desired_change);
325 reset_survivors_after_shrink();
326
327 size_changed = true;
328 }
329 } else {
330 if (Verbose && PrintGC) {
331 if (orig_size == gen_size_limit()) {
332 gclog_or_tty->print_cr("PSYoung generation size at maximum: "
333 SIZE_FORMAT "K", orig_size/K);
334 } else if (orig_size == min_gen_size()) {
335 gclog_or_tty->print_cr("PSYoung generation size at minium: "
336 SIZE_FORMAT "K", orig_size/K);
337 }
338 }
339 }
340
341 if (size_changed) {
342 post_resize();
343
344 if (Verbose && PrintGC) {
345 size_t current_size = virtual_space()->committed_size();
346 gclog_or_tty->print_cr("PSYoung generation size changed: "
347 SIZE_FORMAT "K->" SIZE_FORMAT "K",
348 orig_size/K, current_size/K);
349 }
350 }
351
352 guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
353 virtual_space()->committed_size() == max_size(), "Sanity");
354
355 return true;
356 }
357
358 #ifndef PRODUCT
359 // In the numa case eden is not mangled so a survivor space
360 // moving into a region previously occupied by a survivor
361 // may find an unmangled region. Also in the PS case eden
362 // to-space and from-space may not touch (i.e., there may be
363 // gaps between them due to movement while resizing the
364 // spaces). Those gaps must be mangled.
365 void PSYoungGen::mangle_survivors(MutableSpace* s1,
366 MemRegion s1MR,
367 MutableSpace* s2,
368 MemRegion s2MR) {
369 // Check eden and gap between eden and from-space, in deciding
370 // what to mangle in from-space. Check the gap between from-space
371 // and to-space when deciding what to mangle.
372 //
373 // +--------+ +----+ +---+
374 // | eden | |s1 | |s2 |
375 // +--------+ +----+ +---+
376 // +-------+ +-----+
377 // |s1MR | |s2MR |
378 // +-------+ +-----+
379 // All of survivor-space is properly mangled so find the
380 // upper bound on the mangling for any portion above current s1.
381 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());
382 MemRegion delta1_left;
383 if (s1MR.start() < delta_end) {
384 delta1_left = MemRegion(s1MR.start(), delta_end);
385 s1->mangle_region(delta1_left);
386 }
387 // Find any portion to the right of the current s1.
388 HeapWord* delta_start = MAX2(s1->end(), s1MR.start());
389 MemRegion delta1_right;
390 if (delta_start < s1MR.end()) {
391 delta1_right = MemRegion(delta_start, s1MR.end());
392 s1->mangle_region(delta1_right);
393 }
394
395 // Similarly for the second survivor space except that
396 // any of the new region that overlaps with the current
397 // region of the first survivor space has already been
398 // mangled.
399 delta_end = MIN2(s2->bottom(), s2MR.end());
400 delta_start = MAX2(s2MR.start(), s1->end());
401 MemRegion delta2_left;
402 if (s2MR.start() < delta_end) {
403 delta2_left = MemRegion(s2MR.start(), delta_end);
404 s2->mangle_region(delta2_left);
405 }
406 delta_start = MAX2(s2->end(), s2MR.start());
407 MemRegion delta2_right;
408 if (delta_start < s2MR.end()) {
409 s2->mangle_region(delta2_right);
410 }
411
412 if (TraceZapUnusedHeapArea) {
413 // s1
414 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
415 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
416 s1->bottom(), s1->end(), s1MR.start(), s1MR.end());
417 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
418 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
419 delta1_left.start(), delta1_left.end(), delta1_right.start(),
420 delta1_right.end());
421
422 // s2
423 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
424 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
425 s2->bottom(), s2->end(), s2MR.start(), s2MR.end());
426 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
427 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
428 delta2_left.start(), delta2_left.end(), delta2_right.start(),
429 delta2_right.end());
430 }
431
432 }
433 #endif // NOT PRODUCT
434
435 void PSYoungGen::resize_spaces(size_t requested_eden_size,
436 size_t requested_survivor_size) {
437 assert(UseAdaptiveSizePolicy, "sanity check");
438 assert(requested_eden_size > 0 && requested_survivor_size > 0,
439 "just checking");
440
441 // We require eden and to space to be empty
442 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
443 return;
444 }
445
446 if (PrintAdaptiveSizePolicy && Verbose) {
447 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
448 SIZE_FORMAT
449 ", requested_survivor_size: " SIZE_FORMAT ")",
450 requested_eden_size, requested_survivor_size);
451 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
452 SIZE_FORMAT,
453 eden_space()->bottom(),
454 eden_space()->end(),
455 pointer_delta(eden_space()->end(),
456 eden_space()->bottom(),
457 sizeof(char)));
458 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") "
459 SIZE_FORMAT,
460 from_space()->bottom(),
461 from_space()->end(),
462 pointer_delta(from_space()->end(),
463 from_space()->bottom(),
464 sizeof(char)));
465 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") "
466 SIZE_FORMAT,
467 to_space()->bottom(),
468 to_space()->end(),
469 pointer_delta( to_space()->end(),
470 to_space()->bottom(),
471 sizeof(char)));
472 }
473
474 // There's nothing to do if the new sizes are the same as the current
475 if (requested_survivor_size == to_space()->capacity_in_bytes() &&
476 requested_survivor_size == from_space()->capacity_in_bytes() &&
477 requested_eden_size == eden_space()->capacity_in_bytes()) {
478 if (PrintAdaptiveSizePolicy && Verbose) {
479 gclog_or_tty->print_cr(" capacities are the right sizes, returning");
480 }
481 return;
482 }
483
484 char* eden_start = (char*)eden_space()->bottom();
485 char* eden_end = (char*)eden_space()->end();
486 char* from_start = (char*)from_space()->bottom();
487 char* from_end = (char*)from_space()->end();
488 char* to_start = (char*)to_space()->bottom();
489 char* to_end = (char*)to_space()->end();
490
491 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
492 const size_t alignment = heap->intra_heap_alignment();
493 const bool maintain_minimum =
494 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
495
496 bool eden_from_to_order = from_start < to_start;
497 // Check whether from space is below to space
498 if (eden_from_to_order) {
499 // Eden, from, to
500 eden_from_to_order = true;
501 if (PrintAdaptiveSizePolicy && Verbose) {
502 gclog_or_tty->print_cr(" Eden, from, to:");
503 }
504
505 // Set eden
506 // "requested_eden_size" is a goal for the size of eden
507 // and may not be attainable. "eden_size" below is
508 // calculated based on the location of from-space and
509 // the goal for the size of eden. from-space is
510 // fixed in place because it contains live data.
511 // The calculation is done this way to avoid 32bit
512 // overflow (i.e., eden_start + requested_eden_size
513 // may too large for representation in 32bits).
514 size_t eden_size;
515 if (maintain_minimum) {
516 // Only make eden larger than the requested size if
517 // the minimum size of the generation has to be maintained.
518 // This could be done in general but policy at a higher
519 // level is determining a requested size for eden and that
520 // should be honored unless there is a fundamental reason.
521 eden_size = pointer_delta(from_start,
522 eden_start,
523 sizeof(char));
524 } else {
525 eden_size = MIN2(requested_eden_size,
526 pointer_delta(from_start, eden_start, sizeof(char)));
527 }
528
529 eden_end = eden_start + eden_size;
530 assert(eden_end >= eden_start, "addition overflowed")
531
532 // To may resize into from space as long as it is clear of live data.
533 // From space must remain page aligned, though, so we need to do some
534 // extra calculations.
535
536 // First calculate an optimal to-space
537 to_end = (char*)virtual_space()->high();
538 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
539 sizeof(char));
540
541 // Does the optimal to-space overlap from-space?
542 if (to_start < (char*)from_space()->end()) {
543 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
544
545 // Calculate the minimum offset possible for from_end
546 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));
547
548 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
549 if (from_size == 0) {
550 from_size = alignment;
551 } else {
552 from_size = align_size_up(from_size, alignment);
553 }
554
555 from_end = from_start + from_size;
556 assert(from_end > from_start, "addition overflow or from_size problem");
557
558 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");
559
560 // Now update to_start with the new from_end
561 to_start = MAX2(from_end, to_start);
562 }
563
564 guarantee(to_start != to_end, "to space is zero sized");
565
566 if (PrintAdaptiveSizePolicy && Verbose) {
567 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
568 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
569 eden_start,
570 eden_end,
571 pointer_delta(eden_end, eden_start, sizeof(char)));
572 gclog_or_tty->print_cr(" [from_start .. from_end): "
573 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
574 from_start,
575 from_end,
576 pointer_delta(from_end, from_start, sizeof(char)));
577 gclog_or_tty->print_cr(" [ to_start .. to_end): "
578 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
579 to_start,
580 to_end,
581 pointer_delta( to_end, to_start, sizeof(char)));
582 }
583 } else {
584 // Eden, to, from
585 if (PrintAdaptiveSizePolicy && Verbose) {
586 gclog_or_tty->print_cr(" Eden, to, from:");
587 }
588
589 // To space gets priority over eden resizing. Note that we position
590 // to space as if we were able to resize from space, even though from
591 // space is not modified.
592 // Giving eden priority was tried and gave poorer performance.
593 to_end = (char*)pointer_delta(virtual_space()->high(),
594 (char*)requested_survivor_size,
595 sizeof(char));
596 to_end = MIN2(to_end, from_start);
597 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
598 sizeof(char));
599 // if the space sizes are to be increased by several times then
600 // 'to_start' will point beyond the young generation. In this case
601 // 'to_start' should be adjusted.
602 to_start = MAX2(to_start, eden_start + alignment);
603
604 // Compute how big eden can be, then adjust end.
605 // See comments above on calculating eden_end.
606 size_t eden_size;
607 if (maintain_minimum) {
608 eden_size = pointer_delta(to_start, eden_start, sizeof(char));
609 } else {
610 eden_size = MIN2(requested_eden_size,
611 pointer_delta(to_start, eden_start, sizeof(char)));
612 }
613 eden_end = eden_start + eden_size;
614 assert(eden_end >= eden_start, "addition overflowed")
615
616 // Could choose to not let eden shrink
617 // to_start = MAX2(to_start, eden_end);
618
619 // Don't let eden shrink down to 0 or less.
620 eden_end = MAX2(eden_end, eden_start + alignment);
621 to_start = MAX2(to_start, eden_end);
622
623 if (PrintAdaptiveSizePolicy && Verbose) {
624 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
625 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
626 eden_start,
627 eden_end,
628 pointer_delta(eden_end, eden_start, sizeof(char)));
629 gclog_or_tty->print_cr(" [ to_start .. to_end): "
630 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
631 to_start,
632 to_end,
633 pointer_delta( to_end, to_start, sizeof(char)));
634 gclog_or_tty->print_cr(" [from_start .. from_end): "
635 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
636 from_start,
637 from_end,
638 pointer_delta(from_end, from_start, sizeof(char)));
639 }
640 }
641
642
643 guarantee((HeapWord*)from_start <= from_space()->bottom(),
644 "from start moved to the right");
645 guarantee((HeapWord*)from_end >= from_space()->top(),
646 "from end moved into live data");
647 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
648 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
649 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
650
651 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
652 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
653 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
654
655 // Let's make sure the call to initialize doesn't reset "top"!
656 HeapWord* old_from_top = from_space()->top();
657
658 // For PrintAdaptiveSizePolicy block below
659 size_t old_from = from_space()->capacity_in_bytes();
660 size_t old_to = to_space()->capacity_in_bytes();
661
662 if (ZapUnusedHeapArea) {
663 // NUMA is a special case because a numa space is not mangled
664 // in order to not prematurely bind its address to memory to
665 // the wrong memory (i.e., don't want the GC thread to first
666 // touch the memory). The survivor spaces are not numa
667 // spaces and are mangled.
668 if (UseNUMA) {
669 if (eden_from_to_order) {
670 mangle_survivors(from_space(), fromMR, to_space(), toMR);
671 } else {
672 mangle_survivors(to_space(), toMR, from_space(), fromMR);
673 }
674 }
675
676 // If not mangling the spaces, do some checking to verify that
677 // the spaces are already mangled.
678 // The spaces should be correctly mangled at this point so
679 // do some checking here. Note that they are not being mangled
680 // in the calls to initialize().
681 // Must check mangling before the spaces are reshaped. Otherwise,
682 // the bottom or end of one space may have moved into an area
683 // covered by another space and a failure of the check may
684 // not correctly indicate which space is not properly mangled.
685 HeapWord* limit = (HeapWord*) virtual_space()->high();
686 eden_space()->check_mangled_unused_area(limit);
687 from_space()->check_mangled_unused_area(limit);
688 to_space()->check_mangled_unused_area(limit);
689 }
690 // When an existing space is being initialized, it is not
691 // mangled because the space has been previously mangled.
692 eden_space()->initialize(edenMR,
693 SpaceDecorator::Clear,
694 SpaceDecorator::DontMangle);
695 to_space()->initialize(toMR,
696 SpaceDecorator::Clear,
697 SpaceDecorator::DontMangle);
698 from_space()->initialize(fromMR,
699 SpaceDecorator::DontClear,
700 SpaceDecorator::DontMangle);
701
702 assert(from_space()->top() == old_from_top, "from top changed!");
703
704 if (PrintAdaptiveSizePolicy) {
705 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
706 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
707
708 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
709 "collection: %d "
710 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
711 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
712 heap->total_collections(),
713 old_from, old_to,
714 from_space()->capacity_in_bytes(),
715 to_space()->capacity_in_bytes());
716 gclog_or_tty->cr();
717 }
718 }
719
720 void PSYoungGen::swap_spaces() {
721 MutableSpace* s = from_space();
722 _from_space = to_space();
723 _to_space = s;
724
725 // Now update the decorators.
726 PSMarkSweepDecorator* md = from_mark_sweep();
727 _from_mark_sweep = to_mark_sweep();
728 _to_mark_sweep = md;
729
730 assert(from_mark_sweep()->space() == from_space(), "Sanity");
731 assert(to_mark_sweep()->space() == to_space(), "Sanity");
732 }
733
734 size_t PSYoungGen::capacity_in_bytes() const {
735 return eden_space()->capacity_in_bytes()
736 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
737 }
738
739
740 size_t PSYoungGen::used_in_bytes() const {
741 return eden_space()->used_in_bytes()
742 + from_space()->used_in_bytes(); // to_space() is only used during scavenge
743 }
744
745
746 size_t PSYoungGen::free_in_bytes() const {
747 return eden_space()->free_in_bytes()
748 + from_space()->free_in_bytes(); // to_space() is only used during scavenge
749 }
750
751 size_t PSYoungGen::capacity_in_words() const {
752 return eden_space()->capacity_in_words()
753 + from_space()->capacity_in_words(); // to_space() is only used during scavenge
754 }
755
756
757 size_t PSYoungGen::used_in_words() const {
758 return eden_space()->used_in_words()
759 + from_space()->used_in_words(); // to_space() is only used during scavenge
760 }
761
762
763 size_t PSYoungGen::free_in_words() const {
764 return eden_space()->free_in_words()
765 + from_space()->free_in_words(); // to_space() is only used during scavenge
766 }
767
768 void PSYoungGen::object_iterate(ObjectClosure* blk) {
769 eden_space()->object_iterate(blk);
770 from_space()->object_iterate(blk);
771 to_space()->object_iterate(blk);
772 }
773
774 void PSYoungGen::precompact() {
775 eden_mark_sweep()->precompact();
776 from_mark_sweep()->precompact();
777 to_mark_sweep()->precompact();
778 }
779
780 void PSYoungGen::adjust_pointers() {
781 eden_mark_sweep()->adjust_pointers();
782 from_mark_sweep()->adjust_pointers();
783 to_mark_sweep()->adjust_pointers();
784 }
785
786 void PSYoungGen::compact() {
787 eden_mark_sweep()->compact(ZapUnusedHeapArea);
788 from_mark_sweep()->compact(ZapUnusedHeapArea);
789 // Mark sweep stores preserved markOops in to space, don't disturb!
790 to_mark_sweep()->compact(false);
791 }
792
793 void PSYoungGen::move_and_update(ParCompactionManager* cm) {
794 PSParallelCompact::move_and_update(cm, PSParallelCompact::eden_space_id);
795 PSParallelCompact::move_and_update(cm, PSParallelCompact::from_space_id);
796 PSParallelCompact::move_and_update(cm, PSParallelCompact::to_space_id);
797 }
798
799 void PSYoungGen::print() const { print_on(tty); }
800 void PSYoungGen::print_on(outputStream* st) const {
801 st->print(" %-15s", "PSYoungGen");
802 if (PrintGCDetails && Verbose) {
803 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
804 capacity_in_bytes(), used_in_bytes());
805 } else {
806 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
807 capacity_in_bytes()/K, used_in_bytes()/K);
808 }
809 virtual_space()->print_space_boundaries_on(st);
810 st->print(" eden"); eden_space()->print_on(st);
811 st->print(" from"); from_space()->print_on(st);
812 st->print(" to "); to_space()->print_on(st);
813 }
814
815 void PSYoungGen::print_used_change(size_t prev_used) const {
816 gclog_or_tty->print(" [%s:", name());
817 gclog_or_tty->print(" " SIZE_FORMAT "K"
818 "->" SIZE_FORMAT "K"
819 "(" SIZE_FORMAT "K)",
820 prev_used / K, used_in_bytes() / K,
821 capacity_in_bytes() / K);
822 gclog_or_tty->print("]");
823 }
824
825 size_t PSYoungGen::available_for_expansion() {
826 ShouldNotReachHere();
827 return 0;
828 }
829
830 size_t PSYoungGen::available_for_contraction() {
831 ShouldNotReachHere();
832 return 0;
833 }
834
835 size_t PSYoungGen::available_to_min_gen() {
836 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
837 return virtual_space()->committed_size() - min_gen_size();
838 }
839
840 // This method assumes that from-space has live data and that
841 // any shrinkage of the young gen is limited by location of
842 // from-space.
843 size_t PSYoungGen::available_to_live() {
844 size_t delta_in_survivor = 0;
845 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
846 const size_t space_alignment = heap->intra_heap_alignment();
847 const size_t gen_alignment = heap->young_gen_alignment();
848
849 MutableSpace* space_shrinking = NULL;
850 if (from_space()->end() > to_space()->end()) {
851 space_shrinking = from_space();
852 } else {
853 space_shrinking = to_space();
854 }
855
856 // Include any space that is committed but not included in
857 // the survivor spaces.
858 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
859 "Survivor space beyond high end");
860 size_t unused_committed = pointer_delta(virtual_space()->high(),
861 space_shrinking->end(), sizeof(char));
862
863 if (space_shrinking->is_empty()) {
864 // Don't let the space shrink to 0
865 assert(space_shrinking->capacity_in_bytes() >= space_alignment,
866 "Space is too small");
867 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
868 } else {
869 delta_in_survivor = pointer_delta(space_shrinking->end(),
870 space_shrinking->top(),
871 sizeof(char));
872 }
873
874 size_t delta_in_bytes = unused_committed + delta_in_survivor;
875 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
876 return delta_in_bytes;
877 }
878
879 // Return the number of bytes available for resizing down the young
880 // generation. This is the minimum of
881 // input "bytes"
882 // bytes to the minimum young gen size
883 // bytes to the size currently being used + some small extra
884 size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
885 // Allow shrinkage into the current eden but keep eden large enough
886 // to maintain the minimum young gen size
887 bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
888 return align_size_down(bytes, virtual_space()->alignment());
889 }
890
891 void PSYoungGen::reset_after_change() {
892 ShouldNotReachHere();
893 }
894
895 void PSYoungGen::reset_survivors_after_shrink() {
896 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
897 (HeapWord*)virtual_space()->high_boundary());
898 PSScavenge::reference_processor()->set_span(_reserved);
899
900 MutableSpace* space_shrinking = NULL;
901 if (from_space()->end() > to_space()->end()) {
902 space_shrinking = from_space();
903 } else {
904 space_shrinking = to_space();
905 }
906
907 HeapWord* new_end = (HeapWord*)virtual_space()->high();
908 assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
909 // Was there a shrink of the survivor space?
910 if (new_end < space_shrinking->end()) {
911 MemRegion mr(space_shrinking->bottom(), new_end);
912 space_shrinking->initialize(mr,
913 SpaceDecorator::DontClear,
914 SpaceDecorator::Mangle);
915 }
916 }
917
918 // This method currently does not expect to expand into eden (i.e.,
919 // the virtual space boundaries is expected to be consistent
920 // with the eden boundaries..
921 void PSYoungGen::post_resize() {
922 assert_locked_or_safepoint(Heap_lock);
923 assert((eden_space()->bottom() < to_space()->bottom()) &&
924 (eden_space()->bottom() < from_space()->bottom()),
925 "Eden is assumed to be below the survivor spaces");
926
927 MemRegion cmr((HeapWord*)virtual_space()->low(),
928 (HeapWord*)virtual_space()->high());
929 Universe::heap()->barrier_set()->resize_covered_region(cmr);
930 space_invariants();
931 }
932
933
934
935 void PSYoungGen::update_counters() {
936 if (UsePerfData) {
937 _eden_counters->update_all();
938 _from_counters->update_all();
939 _to_counters->update_all();
940 _gen_counters->update_all();
941 }
942 }
943
944 void PSYoungGen::verify(bool allow_dirty) {
945 eden_space()->verify(allow_dirty);
946 from_space()->verify(allow_dirty);
947 to_space()->verify(allow_dirty);
948 }
949
950 #ifndef PRODUCT
951 void PSYoungGen::record_spaces_top() {
952 assert(ZapUnusedHeapArea, "Not mangling unused space");
953 eden_space()->set_top_for_allocations();
954 from_space()->set_top_for_allocations();
955 to_space()->set_top_for_allocations();
956 }
957 #endif
958
959 void PSYoungGen::try_to_expand_by(size_t expand_bytes) {
960 size_t available_bytes = max_size() - capacity_in_bytes();
961 if (available_bytes == 0) {
962 // cannot expand
963 return;
964 }
965 size_t eden_available_bytes = _max_eden_size - eden_space()->used_in_bytes();
966 size_t survivor_available_bytes = _max_survivor_size - from_space()->used_in_bytes();
967 size_t eden_expand_bytes =
968 (size_t) (expand_bytes * ((double) eden_available_bytes / available_bytes));
969 size_t survivor_expand_bytes =
970 (size_t) (expand_bytes * ((double) survivor_available_bytes / available_bytes));
971
972 // Don't expand unless it's significant
973 if (eden_expand_bytes < MinHeapDeltaBytes) {
974 eden_expand_bytes = 0;
975 }
976 if (survivor_expand_bytes < MinHeapDeltaBytes) {
977 survivor_expand_bytes = 0;
978 }
979
980 if (eden_expand_bytes == 0 && survivor_expand_bytes == 0) {
981 return; // no change, so return now
982 }
983
984 size_t eden_desired_capacity =
985 eden_space()->capacity_in_bytes() + eden_expand_bytes;
986 eden_desired_capacity = MIN2(eden_desired_capacity, _max_eden_size);
987 eden_desired_capacity = align_size_down(eden_desired_capacity,
988 virtual_space()->alignment());
989
990 size_t survivor_desired_capacity =
991 from_space()->capacity_in_bytes() + survivor_expand_bytes;
992 survivor_desired_capacity = MIN2(survivor_desired_capacity, _max_survivor_size);
993 survivor_desired_capacity = align_size_down(survivor_desired_capacity,
994 virtual_space()->alignment());
995
996 if (eden_desired_capacity == eden_space()->capacity_in_bytes()
997 && survivor_desired_capacity == from_space()->capacity_in_bytes()) {
998 return; // no change, so return now
999 }
1000
1001 if (PrintGC) {
1002 gclog_or_tty->print_cr(" Resizing young gen. expand_bytes=%d,%d",
1003 eden_expand_bytes, survivor_expand_bytes);
1004 gclog_or_tty->print("BEFORE: Young Gen: ");
1005 gclog_or_tty->print("eden capacity : " SIZE_FORMAT ", ",
1006 eden_space()->capacity_in_bytes());
1007 gclog_or_tty->print("eden used : " SIZE_FORMAT ", " ,
1008 eden_space()->used_in_bytes());
1009 gclog_or_tty->print("survivor capacity : " SIZE_FORMAT ", ",
1010 from_space()->capacity_in_bytes());
1011 gclog_or_tty->print_cr("survivor used : " SIZE_FORMAT ", " ,
1012 from_space()->used_in_bytes());
1013 }
1014
1015 resize(eden_desired_capacity, survivor_desired_capacity);
1016
1017 if (PrintGC) {
1018 gclog_or_tty->print("AFTER: Young Gen: ");
1019 gclog_or_tty->print("eden capacity : " SIZE_FORMAT ", ",
1020 eden_space()->capacity_in_bytes());
1021 gclog_or_tty->print("eden used : " SIZE_FORMAT ", " ,
1022 eden_space()->used_in_bytes());
1023 gclog_or_tty->print("survivor capacity : " SIZE_FORMAT ", ",
1024 from_space()->capacity_in_bytes());
1025 gclog_or_tty->print_cr("survivor used : " SIZE_FORMAT ", " ,
1026 from_space()->used_in_bytes());
1027 }
1028 }
1029
1030 void PSYoungGen::try_to_shrink_by(size_t shrink_bytes) {
1031 size_t free_bytes = capacity_in_bytes() - used_in_bytes();
1032 if (free_bytes == 0) {
1033 // cannot shrink
1034 return;
1035 }
1036 size_t eden_free_bytes = eden_space()->capacity_in_bytes() - eden_space()->used_in_bytes();
1037 size_t survivor_free_bytes = from_space()->capacity_in_bytes() - from_space()->used_in_bytes();
1038 size_t eden_shrink_bytes =
1039 (size_t) (shrink_bytes * ((double) eden_free_bytes / free_bytes));
1040 size_t survivor_shrink_bytes =
1041 (size_t) (shrink_bytes * ((double) survivor_free_bytes / free_bytes));
1042
1043 // Don't shrink unless it's significant
1044 if (eden_shrink_bytes < MinHeapDeltaBytes) {
1045 eden_shrink_bytes = 0;
1046 }
1047 if (survivor_shrink_bytes < MinHeapDeltaBytes) {
1048 survivor_shrink_bytes = 0;
1049 }
1050
1051 if (eden_shrink_bytes == 0 && survivor_shrink_bytes == 0) {
1052 return; // no change, so return now
1053 }
1054
1055 size_t eden_desired_capacity =
1056 eden_space()->capacity_in_bytes() - eden_shrink_bytes;
1057 eden_desired_capacity = MAX2(eden_desired_capacity, _init_eden_size);
1058 assert(eden_space()->used_in_bytes() <= eden_desired_capacity, "sanity check");
1059 eden_desired_capacity = align_size_down(eden_desired_capacity,
1060 virtual_space()->alignment());
1061
1062 size_t survivor_desired_capacity =
1063 from_space()->capacity_in_bytes() - survivor_shrink_bytes;
1064 survivor_desired_capacity = MAX2(survivor_desired_capacity, _init_survivor_size);
1065 assert(from_space()->used_in_bytes() <= survivor_desired_capacity, "sanity check");
1066 survivor_desired_capacity = align_size_down(survivor_desired_capacity,
1067 virtual_space()->alignment());
1068
1069 if (eden_desired_capacity == eden_space()->capacity_in_bytes()
1070 && survivor_desired_capacity == from_space()->capacity_in_bytes()) {
1071 return; // no change, so return now
1072 }
1073
1074 if (PrintGC) {
1075 gclog_or_tty->print_cr(" Resizing young gen. shrink_bytes=%d,%d",
1076 eden_shrink_bytes, survivor_shrink_bytes);
1077 gclog_or_tty->print("BEFORE: Young Gen: ");
1078 gclog_or_tty->print("eden capacity : " SIZE_FORMAT ", ",
1079 eden_space()->capacity_in_bytes());
1080 gclog_or_tty->print("eden used : " SIZE_FORMAT ", " ,
1081 eden_space()->used_in_bytes());
1082 gclog_or_tty->print("survivor capacity : " SIZE_FORMAT ", ",
1083 from_space()->capacity_in_bytes());
1084 gclog_or_tty->print_cr("survivor used : " SIZE_FORMAT ", " ,
1085 from_space()->used_in_bytes());
1086 }
1087
1088 resize(eden_desired_capacity, survivor_desired_capacity);
1089
1090 if (PrintGC) {
1091 gclog_or_tty->print("AFTER: Young Gen: ");
1092 gclog_or_tty->print("eden capacity : " SIZE_FORMAT ", ",
1093 eden_space()->capacity_in_bytes());
1094 gclog_or_tty->print("eden used : " SIZE_FORMAT ", " ,
1095 eden_space()->used_in_bytes());
1096 gclog_or_tty->print("survivor capacity : " SIZE_FORMAT ", ",
1097 from_space()->capacity_in_bytes());
1098 gclog_or_tty->print_cr("survivor used : " SIZE_FORMAT ", " ,
1099 from_space()->used_in_bytes());
1100 }
1101 }