1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
27 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
28 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
29 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
30 #include "gc_implementation/shared/gcUtil.hpp"
31 #include "gc_implementation/shared/mutableNUMASpace.hpp"
32 #include "gc_implementation/shared/spaceDecorator.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/java.hpp"
35
36 PSYoungGen::PSYoungGen(size_t initial_size,
37 size_t min_size,
38 size_t max_size) :
39 _init_gen_size(initial_size),
40 _min_gen_size(min_size),
41 _max_gen_size(max_size)
42 {}
43
44 void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
45 assert(_init_gen_size != 0, "Should have a finite size");
46 _virtual_space = new PSVirtualSpace(rs, alignment);
47 if (!virtual_space()->expand_by(_init_gen_size)) {
48 vm_exit_during_initialization("Could not reserve enough space for "
49 "object heap");
50 }
51 }
52
53 void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
54 initialize_virtual_space(rs, alignment);
55 initialize_work();
56 }
57
58 void PSYoungGen::initialize_work() {
59
60 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
61 (HeapWord*)virtual_space()->high_boundary());
62
63 MemRegion cmr((HeapWord*)virtual_space()->low(),
64 (HeapWord*)virtual_space()->high());
65 Universe::heap()->barrier_set()->resize_covered_region(cmr);
66
67 if (ZapUnusedHeapArea) {
68 // Mangle newly committed space immediately because it
69 // can be done here more simply that after the new
70 // spaces have been computed.
71 SpaceMangler::mangle_region(cmr);
72 }
73
74 if (UseNUMA) {
75 _eden_space = new MutableNUMASpace(virtual_space()->alignment());
76 } else {
77 _eden_space = new MutableSpace(virtual_space()->alignment());
78 }
79 _from_space = new MutableSpace(virtual_space()->alignment());
80 _to_space = new MutableSpace(virtual_space()->alignment());
81
82 if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
83 vm_exit_during_initialization("Could not allocate a young gen space");
84 }
85
86 // Allocate the mark sweep views of spaces
87 _eden_mark_sweep =
88 new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);
89 _from_mark_sweep =
90 new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);
91 _to_mark_sweep =
92 new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);
93
94 if (_eden_mark_sweep == NULL ||
95 _from_mark_sweep == NULL ||
96 _to_mark_sweep == NULL) {
97 vm_exit_during_initialization("Could not complete allocation"
98 " of the young generation");
99 }
100
101 // Generation Counters - generation 0, 3 subspaces
102 _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);
103
104 // Compute maximum space sizes for performance counters
105 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
106 size_t alignment = heap->intra_heap_alignment();
107 size_t size = virtual_space()->reserved_size();
108
109 size_t max_survivor_size;
110 size_t max_eden_size;
111
112 if (UseAdaptiveSizePolicy) {
113 max_survivor_size = size / MinSurvivorRatio;
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 minimum survivor size. The minimum survivor
122 // size for UseAdaptiveSizePolicy is one alignment.
123 max_eden_size = size - 2 * alignment;
124 } else {
125 max_survivor_size = size / InitialSurvivorRatio;
126
127 // round the survivor space size down to the nearest alignment
128 // and make sure its size is greater than 0.
129 max_survivor_size = align_size_down(max_survivor_size, alignment);
130 max_survivor_size = MAX2(max_survivor_size, alignment);
131
132 // set the maximum size of eden to be the size of the young gen
133 // less two times the survivor size when the generation is 100%
134 // committed. The minimum survivor size for -UseAdaptiveSizePolicy
135 // is dependent on the committed portion (current capacity) of the
136 // generation - the less space committed, the smaller the survivor
137 // space, possibly as small as an alignment. However, we are interested
138 // in the case where the young generation is 100% committed, as this
139 // is the point where eden reaches its maximum size. At this point,
140 // the size of a survivor space is max_survivor_size.
141 max_eden_size = size - 2 * max_survivor_size;
142 }
143
144 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
145 _gen_counters);
146 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
147 _gen_counters);
148 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
149 _gen_counters);
150
151 compute_initial_space_boundaries();
152 }
153
154 void PSYoungGen::compute_initial_space_boundaries() {
155 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
156 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
157
158 // Compute sizes
159 size_t alignment = heap->intra_heap_alignment();
160 size_t size = virtual_space()->committed_size();
161 assert(size >= 3 * alignment, "Young space is not large enough for eden + 2 survivors");
162
163 size_t survivor_size = size / InitialSurvivorRatio;
164 survivor_size = align_size_down(survivor_size, alignment);
165 // ... but never less than an alignment
166 survivor_size = MAX2(survivor_size, alignment);
167
168 // Young generation is eden + 2 survivor spaces
169 size_t eden_size = size - (2 * survivor_size);
170
171 // Now go ahead and set 'em.
172 set_space_boundaries(eden_size, survivor_size);
173 space_invariants();
174
175 if (UsePerfData) {
176 _eden_counters->update_capacity();
177 _from_counters->update_capacity();
178 _to_counters->update_capacity();
179 }
180 }
181
182 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
183 assert(eden_size < virtual_space()->committed_size(), "just checking");
184 assert(eden_size > 0 && survivor_size > 0, "just checking");
185
186 // Initial layout is Eden, to, from. After swapping survivor spaces,
187 // that leaves us with Eden, from, to, which is step one in our two
188 // step resize-with-live-data procedure.
189 char *eden_start = virtual_space()->low();
190 char *to_start = eden_start + eden_size;
191 char *from_start = to_start + survivor_size;
192 char *from_end = from_start + survivor_size;
193
194 assert(from_end == virtual_space()->high(), "just checking");
195 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
196 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
197 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
198
199 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
200 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
201 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
202
203 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
204 to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
205 from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
206 }
207
208 #ifndef PRODUCT
209 void PSYoungGen::space_invariants() {
210 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
211 const size_t alignment = heap->intra_heap_alignment();
212
213 // Currently, our eden size cannot shrink to zero
214 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
215 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
216 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
217
218 // Relationship of spaces to each other
219 char* eden_start = (char*)eden_space()->bottom();
220 char* eden_end = (char*)eden_space()->end();
221 char* from_start = (char*)from_space()->bottom();
222 char* from_end = (char*)from_space()->end();
223 char* to_start = (char*)to_space()->bottom();
224 char* to_end = (char*)to_space()->end();
225
226 guarantee(eden_start >= virtual_space()->low(), "eden bottom");
227 guarantee(eden_start < eden_end, "eden space consistency");
228 guarantee(from_start < from_end, "from space consistency");
229 guarantee(to_start < to_end, "to space consistency");
230
231 // Check whether from space is below to space
232 if (from_start < to_start) {
233 // Eden, from, to
234 guarantee(eden_end <= from_start, "eden/from boundary");
235 guarantee(from_end <= to_start, "from/to boundary");
236 guarantee(to_end <= virtual_space()->high(), "to end");
237 } else {
238 // Eden, to, from
239 guarantee(eden_end <= to_start, "eden/to boundary");
240 guarantee(to_end <= from_start, "to/from boundary");
241 guarantee(from_end <= virtual_space()->high(), "from end");
242 }
243
244 // More checks that the virtual space is consistent with the spaces
245 assert(virtual_space()->committed_size() >=
246 (eden_space()->capacity_in_bytes() +
247 to_space()->capacity_in_bytes() +
248 from_space()->capacity_in_bytes()), "Committed size is inconsistent");
249 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
250 "Space invariant");
251 char* eden_top = (char*)eden_space()->top();
252 char* from_top = (char*)from_space()->top();
253 char* to_top = (char*)to_space()->top();
254 assert(eden_top <= virtual_space()->high(), "eden top");
255 assert(from_top <= virtual_space()->high(), "from top");
256 assert(to_top <= virtual_space()->high(), "to top");
257
258 virtual_space()->verify();
259 }
260 #endif
261
262 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
263 // Resize the generation if needed. If the generation resize
264 // reports false, do not attempt to resize the spaces.
265 if (resize_generation(eden_size, survivor_size)) {
266 // Then we lay out the spaces inside the generation
267 resize_spaces(eden_size, survivor_size);
268
269 space_invariants();
270
271 if (PrintAdaptiveSizePolicy && Verbose) {
272 gclog_or_tty->print_cr("Young generation size: "
273 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
274 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
275 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
276 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
277 _max_gen_size, min_gen_size());
278 }
279 }
280 }
281
282
283 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
284 const size_t alignment = virtual_space()->alignment();
285 size_t orig_size = virtual_space()->committed_size();
286 bool size_changed = false;
287
288 // There used to be this guarantee there.
289 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
290 // Code below forces this requirement. In addition the desired eden
291 // size and disired survivor sizes are desired goals and may
292 // exceed the total generation size.
293
294 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
295
296 // Adjust new generation size
297 const size_t eden_plus_survivors =
298 align_size_up(eden_size + 2 * survivor_size, alignment);
299 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
300 min_gen_size());
301 assert(desired_size <= max_size(), "just checking");
302
303 if (desired_size > orig_size) {
304 // Grow the generation
305 size_t change = desired_size - orig_size;
306 assert(change % alignment == 0, "just checking");
307 HeapWord* prev_high = (HeapWord*) virtual_space()->high();
308 if (!virtual_space()->expand_by(change)) {
309 return false; // Error if we fail to resize!
310 }
311 if (ZapUnusedHeapArea) {
312 // Mangle newly committed space immediately because it
313 // can be done here more simply that after the new
314 // spaces have been computed.
315 HeapWord* new_high = (HeapWord*) virtual_space()->high();
316 MemRegion mangle_region(prev_high, new_high);
317 SpaceMangler::mangle_region(mangle_region);
318 }
319 size_changed = true;
320 } else if (desired_size < orig_size) {
321 size_t desired_change = orig_size - desired_size;
322 assert(desired_change % alignment == 0, "just checking");
323
324 desired_change = limit_gen_shrink(desired_change);
325
326 if (desired_change > 0) {
327 virtual_space()->shrink_by(desired_change);
328 reset_survivors_after_shrink();
329
330 size_changed = true;
331 }
332 } else {
333 if (Verbose && PrintGC) {
334 if (orig_size == gen_size_limit()) {
335 gclog_or_tty->print_cr("PSYoung generation size at maximum: "
336 SIZE_FORMAT "K", orig_size/K);
337 } else if (orig_size == min_gen_size()) {
338 gclog_or_tty->print_cr("PSYoung generation size at minium: "
339 SIZE_FORMAT "K", orig_size/K);
340 }
341 }
342 }
343
344 if (size_changed) {
345 post_resize();
346
347 if (Verbose && PrintGC) {
348 size_t current_size = virtual_space()->committed_size();
349 gclog_or_tty->print_cr("PSYoung generation size changed: "
350 SIZE_FORMAT "K->" SIZE_FORMAT "K",
351 orig_size/K, current_size/K);
352 }
353 }
354
355 guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
356 virtual_space()->committed_size() == max_size(), "Sanity");
357
358 return true;
359 }
360
361 #ifndef PRODUCT
362 // In the numa case eden is not mangled so a survivor space
363 // moving into a region previously occupied by a survivor
364 // may find an unmangled region. Also in the PS case eden
365 // to-space and from-space may not touch (i.e., there may be
366 // gaps between them due to movement while resizing the
367 // spaces). Those gaps must be mangled.
368 void PSYoungGen::mangle_survivors(MutableSpace* s1,
369 MemRegion s1MR,
370 MutableSpace* s2,
371 MemRegion s2MR) {
372 // Check eden and gap between eden and from-space, in deciding
373 // what to mangle in from-space. Check the gap between from-space
374 // and to-space when deciding what to mangle.
375 //
376 // +--------+ +----+ +---+
377 // | eden | |s1 | |s2 |
378 // +--------+ +----+ +---+
379 // +-------+ +-----+
380 // |s1MR | |s2MR |
381 // +-------+ +-----+
382 // All of survivor-space is properly mangled so find the
383 // upper bound on the mangling for any portion above current s1.
384 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());
385 MemRegion delta1_left;
386 if (s1MR.start() < delta_end) {
387 delta1_left = MemRegion(s1MR.start(), delta_end);
388 s1->mangle_region(delta1_left);
389 }
390 // Find any portion to the right of the current s1.
391 HeapWord* delta_start = MAX2(s1->end(), s1MR.start());
392 MemRegion delta1_right;
393 if (delta_start < s1MR.end()) {
394 delta1_right = MemRegion(delta_start, s1MR.end());
395 s1->mangle_region(delta1_right);
396 }
397
398 // Similarly for the second survivor space except that
399 // any of the new region that overlaps with the current
400 // region of the first survivor space has already been
401 // mangled.
402 delta_end = MIN2(s2->bottom(), s2MR.end());
403 delta_start = MAX2(s2MR.start(), s1->end());
404 MemRegion delta2_left;
405 if (s2MR.start() < delta_end) {
406 delta2_left = MemRegion(s2MR.start(), delta_end);
407 s2->mangle_region(delta2_left);
408 }
409 delta_start = MAX2(s2->end(), s2MR.start());
410 MemRegion delta2_right;
411 if (delta_start < s2MR.end()) {
412 s2->mangle_region(delta2_right);
413 }
414
415 if (TraceZapUnusedHeapArea) {
416 // s1
417 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
418 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
419 s1->bottom(), s1->end(), s1MR.start(), s1MR.end());
420 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
421 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
422 delta1_left.start(), delta1_left.end(), delta1_right.start(),
423 delta1_right.end());
424
425 // s2
426 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
427 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
428 s2->bottom(), s2->end(), s2MR.start(), s2MR.end());
429 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
430 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
431 delta2_left.start(), delta2_left.end(), delta2_right.start(),
432 delta2_right.end());
433 }
434
435 }
436 #endif // NOT PRODUCT
437
438 void PSYoungGen::resize_spaces(size_t requested_eden_size,
439 size_t requested_survivor_size) {
440 assert(UseAdaptiveSizePolicy, "sanity check");
441 assert(requested_eden_size > 0 && requested_survivor_size > 0,
442 "just checking");
443
444 // We require eden and to space to be empty
445 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
446 return;
447 }
448
449 if (PrintAdaptiveSizePolicy && Verbose) {
450 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
451 SIZE_FORMAT
452 ", requested_survivor_size: " SIZE_FORMAT ")",
453 requested_eden_size, requested_survivor_size);
454 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
455 SIZE_FORMAT,
456 eden_space()->bottom(),
457 eden_space()->end(),
458 pointer_delta(eden_space()->end(),
459 eden_space()->bottom(),
460 sizeof(char)));
461 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") "
462 SIZE_FORMAT,
463 from_space()->bottom(),
464 from_space()->end(),
465 pointer_delta(from_space()->end(),
466 from_space()->bottom(),
467 sizeof(char)));
468 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") "
469 SIZE_FORMAT,
470 to_space()->bottom(),
471 to_space()->end(),
472 pointer_delta( to_space()->end(),
473 to_space()->bottom(),
474 sizeof(char)));
475 }
476
477 // There's nothing to do if the new sizes are the same as the current
478 if (requested_survivor_size == to_space()->capacity_in_bytes() &&
479 requested_survivor_size == from_space()->capacity_in_bytes() &&
480 requested_eden_size == eden_space()->capacity_in_bytes()) {
481 if (PrintAdaptiveSizePolicy && Verbose) {
482 gclog_or_tty->print_cr(" capacities are the right sizes, returning");
483 }
484 return;
485 }
486
487 char* eden_start = (char*)eden_space()->bottom();
488 char* eden_end = (char*)eden_space()->end();
489 char* from_start = (char*)from_space()->bottom();
490 char* from_end = (char*)from_space()->end();
491 char* to_start = (char*)to_space()->bottom();
492 char* to_end = (char*)to_space()->end();
493
494 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
495 const size_t alignment = heap->intra_heap_alignment();
496 const bool maintain_minimum =
497 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
498
499 bool eden_from_to_order = from_start < to_start;
500 // Check whether from space is below to space
501 if (eden_from_to_order) {
502 // Eden, from, to
503 eden_from_to_order = true;
504 if (PrintAdaptiveSizePolicy && Verbose) {
505 gclog_or_tty->print_cr(" Eden, from, to:");
506 }
507
508 // Set eden
509 // "requested_eden_size" is a goal for the size of eden
510 // and may not be attainable. "eden_size" below is
511 // calculated based on the location of from-space and
512 // the goal for the size of eden. from-space is
513 // fixed in place because it contains live data.
514 // The calculation is done this way to avoid 32bit
515 // overflow (i.e., eden_start + requested_eden_size
516 // may too large for representation in 32bits).
517 size_t eden_size;
518 if (maintain_minimum) {
519 // Only make eden larger than the requested size if
520 // the minimum size of the generation has to be maintained.
521 // This could be done in general but policy at a higher
522 // level is determining a requested size for eden and that
523 // should be honored unless there is a fundamental reason.
524 eden_size = pointer_delta(from_start,
525 eden_start,
526 sizeof(char));
527 } else {
528 eden_size = MIN2(requested_eden_size,
529 pointer_delta(from_start, eden_start, sizeof(char)));
530 }
531
532 eden_end = eden_start + eden_size;
533 assert(eden_end >= eden_start, "addition overflowed");
534
535 // To may resize into from space as long as it is clear of live data.
536 // From space must remain page aligned, though, so we need to do some
537 // extra calculations.
538
539 // First calculate an optimal to-space
540 to_end = (char*)virtual_space()->high();
541 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
542 sizeof(char));
543
544 // Does the optimal to-space overlap from-space?
545 if (to_start < (char*)from_space()->end()) {
546 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
547
548 // Calculate the minimum offset possible for from_end
549 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));
550
551 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
552 if (from_size == 0) {
553 from_size = alignment;
554 } else {
555 from_size = align_size_up(from_size, alignment);
556 }
557
558 from_end = from_start + from_size;
559 assert(from_end > from_start, "addition overflow or from_size problem");
560
561 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");
562
563 // Now update to_start with the new from_end
564 to_start = MAX2(from_end, to_start);
565 }
566
567 guarantee(to_start != to_end, "to space is zero sized");
568
569 if (PrintAdaptiveSizePolicy && Verbose) {
570 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
571 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
572 eden_start,
573 eden_end,
574 pointer_delta(eden_end, eden_start, sizeof(char)));
575 gclog_or_tty->print_cr(" [from_start .. from_end): "
576 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
577 from_start,
578 from_end,
579 pointer_delta(from_end, from_start, sizeof(char)));
580 gclog_or_tty->print_cr(" [ to_start .. to_end): "
581 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
582 to_start,
583 to_end,
584 pointer_delta( to_end, to_start, sizeof(char)));
585 }
586 } else {
587 // Eden, to, from
588 if (PrintAdaptiveSizePolicy && Verbose) {
589 gclog_or_tty->print_cr(" Eden, to, from:");
590 }
591
592 // To space gets priority over eden resizing. Note that we position
593 // to space as if we were able to resize from space, even though from
594 // space is not modified.
595 // Giving eden priority was tried and gave poorer performance.
596 to_end = (char*)pointer_delta(virtual_space()->high(),
597 (char*)requested_survivor_size,
598 sizeof(char));
599 to_end = MIN2(to_end, from_start);
600 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
601 sizeof(char));
602 // if the space sizes are to be increased by several times then
603 // 'to_start' will point beyond the young generation. In this case
604 // 'to_start' should be adjusted.
605 to_start = MAX2(to_start, eden_start + alignment);
606
607 // Compute how big eden can be, then adjust end.
608 // See comments above on calculating eden_end.
609 size_t eden_size;
610 if (maintain_minimum) {
611 eden_size = pointer_delta(to_start, eden_start, sizeof(char));
612 } else {
613 eden_size = MIN2(requested_eden_size,
614 pointer_delta(to_start, eden_start, sizeof(char)));
615 }
616 eden_end = eden_start + eden_size;
617 assert(eden_end >= eden_start, "addition overflowed");
618
619 // Could choose to not let eden shrink
620 // to_start = MAX2(to_start, eden_end);
621
622 // Don't let eden shrink down to 0 or less.
623 eden_end = MAX2(eden_end, eden_start + alignment);
624 to_start = MAX2(to_start, eden_end);
625
626 if (PrintAdaptiveSizePolicy && Verbose) {
627 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
628 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
629 eden_start,
630 eden_end,
631 pointer_delta(eden_end, eden_start, sizeof(char)));
632 gclog_or_tty->print_cr(" [ to_start .. to_end): "
633 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
634 to_start,
635 to_end,
636 pointer_delta( to_end, to_start, sizeof(char)));
637 gclog_or_tty->print_cr(" [from_start .. from_end): "
638 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
639 from_start,
640 from_end,
641 pointer_delta(from_end, from_start, sizeof(char)));
642 }
643 }
644
645
646 guarantee((HeapWord*)from_start <= from_space()->bottom(),
647 "from start moved to the right");
648 guarantee((HeapWord*)from_end >= from_space()->top(),
649 "from end moved into live data");
650 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
651 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
652 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
653
654 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
655 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
656 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
657
658 // Let's make sure the call to initialize doesn't reset "top"!
659 HeapWord* old_from_top = from_space()->top();
660
661 // For PrintAdaptiveSizePolicy block below
662 size_t old_from = from_space()->capacity_in_bytes();
663 size_t old_to = to_space()->capacity_in_bytes();
664
665 if (ZapUnusedHeapArea) {
666 // NUMA is a special case because a numa space is not mangled
667 // in order to not prematurely bind its address to memory to
668 // the wrong memory (i.e., don't want the GC thread to first
669 // touch the memory). The survivor spaces are not numa
670 // spaces and are mangled.
671 if (UseNUMA) {
672 if (eden_from_to_order) {
673 mangle_survivors(from_space(), fromMR, to_space(), toMR);
674 } else {
675 mangle_survivors(to_space(), toMR, from_space(), fromMR);
676 }
677 }
678
679 // If not mangling the spaces, do some checking to verify that
680 // the spaces are already mangled.
681 // The spaces should be correctly mangled at this point so
682 // do some checking here. Note that they are not being mangled
683 // in the calls to initialize().
684 // Must check mangling before the spaces are reshaped. Otherwise,
685 // the bottom or end of one space may have moved into an area
686 // covered by another space and a failure of the check may
687 // not correctly indicate which space is not properly mangled.
688 HeapWord* limit = (HeapWord*) virtual_space()->high();
689 eden_space()->check_mangled_unused_area(limit);
690 from_space()->check_mangled_unused_area(limit);
691 to_space()->check_mangled_unused_area(limit);
692 }
693 // When an existing space is being initialized, it is not
694 // mangled because the space has been previously mangled.
695 eden_space()->initialize(edenMR,
696 SpaceDecorator::Clear,
697 SpaceDecorator::DontMangle);
698 to_space()->initialize(toMR,
699 SpaceDecorator::Clear,
700 SpaceDecorator::DontMangle);
701 from_space()->initialize(fromMR,
702 SpaceDecorator::DontClear,
703 SpaceDecorator::DontMangle);
704
705 assert(from_space()->top() == old_from_top, "from top changed!");
706
707 if (PrintAdaptiveSizePolicy) {
708 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
709 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
710
711 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
712 "collection: %d "
713 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
714 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
715 heap->total_collections(),
716 old_from, old_to,
717 from_space()->capacity_in_bytes(),
718 to_space()->capacity_in_bytes());
719 gclog_or_tty->cr();
720 }
721 }
722
723 void PSYoungGen::swap_spaces() {
724 MutableSpace* s = from_space();
725 _from_space = to_space();
726 _to_space = s;
727
728 // Now update the decorators.
729 PSMarkSweepDecorator* md = from_mark_sweep();
730 _from_mark_sweep = to_mark_sweep();
731 _to_mark_sweep = md;
732
733 assert(from_mark_sweep()->space() == from_space(), "Sanity");
734 assert(to_mark_sweep()->space() == to_space(), "Sanity");
735 }
736
737 size_t PSYoungGen::capacity_in_bytes() const {
738 return eden_space()->capacity_in_bytes()
739 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
740 }
741
742
743 size_t PSYoungGen::used_in_bytes() const {
744 return eden_space()->used_in_bytes()
745 + from_space()->used_in_bytes(); // to_space() is only used during scavenge
746 }
747
748
749 size_t PSYoungGen::free_in_bytes() const {
750 return eden_space()->free_in_bytes()
751 + from_space()->free_in_bytes(); // to_space() is only used during scavenge
752 }
753
754 size_t PSYoungGen::capacity_in_words() const {
755 return eden_space()->capacity_in_words()
756 + from_space()->capacity_in_words(); // to_space() is only used during scavenge
757 }
758
759
760 size_t PSYoungGen::used_in_words() const {
761 return eden_space()->used_in_words()
762 + from_space()->used_in_words(); // to_space() is only used during scavenge
763 }
764
765
766 size_t PSYoungGen::free_in_words() const {
767 return eden_space()->free_in_words()
768 + from_space()->free_in_words(); // to_space() is only used during scavenge
769 }
770
771 void PSYoungGen::object_iterate(ObjectClosure* blk) {
772 eden_space()->object_iterate(blk);
773 from_space()->object_iterate(blk);
774 to_space()->object_iterate(blk);
775 }
776
777 void PSYoungGen::precompact() {
778 eden_mark_sweep()->precompact();
779 from_mark_sweep()->precompact();
780 to_mark_sweep()->precompact();
781 }
782
783 void PSYoungGen::adjust_pointers() {
784 eden_mark_sweep()->adjust_pointers();
785 from_mark_sweep()->adjust_pointers();
786 to_mark_sweep()->adjust_pointers();
787 }
788
789 void PSYoungGen::compact() {
790 eden_mark_sweep()->compact(ZapUnusedHeapArea);
791 from_mark_sweep()->compact(ZapUnusedHeapArea);
792 // Mark sweep stores preserved markOops in to space, don't disturb!
793 to_mark_sweep()->compact(false);
794 }
795
796 void PSYoungGen::print() const { print_on(tty); }
797 void PSYoungGen::print_on(outputStream* st) const {
798 st->print(" %-15s", "PSYoungGen");
799 if (PrintGCDetails && Verbose) {
800 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
801 capacity_in_bytes(), used_in_bytes());
802 } else {
803 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
804 capacity_in_bytes()/K, used_in_bytes()/K);
805 }
806 virtual_space()->print_space_boundaries_on(st);
807 st->print(" eden"); eden_space()->print_on(st);
808 st->print(" from"); from_space()->print_on(st);
809 st->print(" to "); to_space()->print_on(st);
810 }
811
812 // Note that a space is not printed before the [NAME:
813 void PSYoungGen::print_used_change(size_t prev_used) const {
814 gclog_or_tty->print("[%s:", name());
815 gclog_or_tty->print(" " SIZE_FORMAT "K"
816 "->" SIZE_FORMAT "K"
817 "(" SIZE_FORMAT "K)",
818 prev_used / K, used_in_bytes() / K,
819 capacity_in_bytes() / K);
820 gclog_or_tty->print("]");
821 }
822
823 size_t PSYoungGen::available_for_expansion() {
824 ShouldNotReachHere();
825 return 0;
826 }
827
828 size_t PSYoungGen::available_for_contraction() {
829 ShouldNotReachHere();
830 return 0;
831 }
832
833 size_t PSYoungGen::available_to_min_gen() {
834 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
835 return virtual_space()->committed_size() - min_gen_size();
836 }
837
838 // This method assumes that from-space has live data and that
839 // any shrinkage of the young gen is limited by location of
840 // from-space.
841 size_t PSYoungGen::available_to_live() {
842 size_t delta_in_survivor = 0;
843 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
844 const size_t space_alignment = heap->intra_heap_alignment();
845 const size_t gen_alignment = heap->young_gen_alignment();
846
847 MutableSpace* space_shrinking = NULL;
848 if (from_space()->end() > to_space()->end()) {
849 space_shrinking = from_space();
850 } else {
851 space_shrinking = to_space();
852 }
853
854 // Include any space that is committed but not included in
855 // the survivor spaces.
856 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
857 "Survivor space beyond high end");
858 size_t unused_committed = pointer_delta(virtual_space()->high(),
859 space_shrinking->end(), sizeof(char));
860
861 if (space_shrinking->is_empty()) {
862 // Don't let the space shrink to 0
863 assert(space_shrinking->capacity_in_bytes() >= space_alignment,
864 "Space is too small");
865 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
866 } else {
867 delta_in_survivor = pointer_delta(space_shrinking->end(),
868 space_shrinking->top(),
869 sizeof(char));
870 }
871
872 size_t delta_in_bytes = unused_committed + delta_in_survivor;
873 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
874 return delta_in_bytes;
875 }
876
877 // Return the number of bytes available for resizing down the young
878 // generation. This is the minimum of
879 // input "bytes"
880 // bytes to the minimum young gen size
881 // bytes to the size currently being used + some small extra
882 size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
883 // Allow shrinkage into the current eden but keep eden large enough
884 // to maintain the minimum young gen size
885 bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
886 return align_size_down(bytes, virtual_space()->alignment());
887 }
888
889 void PSYoungGen::reset_after_change() {
890 ShouldNotReachHere();
891 }
892
893 void PSYoungGen::reset_survivors_after_shrink() {
894 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
895 (HeapWord*)virtual_space()->high_boundary());
896 PSScavenge::reference_processor()->set_span(_reserved);
897
898 MutableSpace* space_shrinking = NULL;
899 if (from_space()->end() > to_space()->end()) {
900 space_shrinking = from_space();
901 } else {
902 space_shrinking = to_space();
903 }
904
905 HeapWord* new_end = (HeapWord*)virtual_space()->high();
906 assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
907 // Was there a shrink of the survivor space?
908 if (new_end < space_shrinking->end()) {
909 MemRegion mr(space_shrinking->bottom(), new_end);
910 space_shrinking->initialize(mr,
911 SpaceDecorator::DontClear,
912 SpaceDecorator::Mangle);
913 }
914 }
915
916 // This method currently does not expect to expand into eden (i.e.,
917 // the virtual space boundaries is expected to be consistent
918 // with the eden boundaries..
919 void PSYoungGen::post_resize() {
920 assert_locked_or_safepoint(Heap_lock);
921 assert((eden_space()->bottom() < to_space()->bottom()) &&
922 (eden_space()->bottom() < from_space()->bottom()),
923 "Eden is assumed to be below the survivor spaces");
924
925 MemRegion cmr((HeapWord*)virtual_space()->low(),
926 (HeapWord*)virtual_space()->high());
927 Universe::heap()->barrier_set()->resize_covered_region(cmr);
928 space_invariants();
929 }
930
931
932
933 void PSYoungGen::update_counters() {
934 if (UsePerfData) {
935 _eden_counters->update_all();
936 _from_counters->update_all();
937 _to_counters->update_all();
938 _gen_counters->update_all();
939 }
940 }
941
942 void PSYoungGen::verify() {
943 eden_space()->verify();
944 from_space()->verify();
945 to_space()->verify();
946 }
947
948 #ifndef PRODUCT
949 void PSYoungGen::record_spaces_top() {
950 assert(ZapUnusedHeapArea, "Not mangling unused space");
951 eden_space()->set_top_for_allocations();
952 from_space()->set_top_for_allocations();
953 to_space()->set_top_for_allocations();
954 }
955 #endif