1 /*
2 * Copyright (c) 2001, 2014, 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, _min_gen_size,
103 _max_gen_size, _virtual_space);
104
105 // Compute maximum space sizes for performance counters
106 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
107 size_t alignment = heap->space_alignment();
108 size_t size = virtual_space()->reserved_size();
109
110 size_t max_survivor_size;
111 size_t max_eden_size;
112
113 if (UseAdaptiveSizePolicy) {
114 max_survivor_size = size / MinSurvivorRatio;
115
116 // round the survivor space size down to the nearest alignment
117 // and make sure its size is greater than 0.
118 max_survivor_size = align_size_down(max_survivor_size, alignment);
119 max_survivor_size = MAX2(max_survivor_size, alignment);
120
121 // set the maximum size of eden to be the size of the young gen
122 // less two times the minimum survivor size. The minimum survivor
123 // size for UseAdaptiveSizePolicy is one alignment.
124 max_eden_size = size - 2 * alignment;
125 } else {
126 max_survivor_size = size / InitialSurvivorRatio;
127
128 // round the survivor space size down to the nearest alignment
129 // and make sure its size is greater than 0.
130 max_survivor_size = align_size_down(max_survivor_size, alignment);
131 max_survivor_size = MAX2(max_survivor_size, alignment);
132
133 // set the maximum size of eden to be the size of the young gen
134 // less two times the survivor size when the generation is 100%
135 // committed. The minimum survivor size for -UseAdaptiveSizePolicy
136 // is dependent on the committed portion (current capacity) of the
137 // generation - the less space committed, the smaller the survivor
138 // space, possibly as small as an alignment. However, we are interested
139 // in the case where the young generation is 100% committed, as this
140 // is the point where eden reaches its maximum size. At this point,
141 // the size of a survivor space is max_survivor_size.
142 max_eden_size = size - 2 * max_survivor_size;
143 }
144
145 _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
146 _gen_counters);
147 _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
148 _gen_counters);
149 _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
150 _gen_counters);
151
152 compute_initial_space_boundaries();
153 }
154
155 void PSYoungGen::compute_initial_space_boundaries() {
156 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
157 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
158
159 // Compute sizes
160 size_t alignment = heap->space_alignment();
161 size_t size = virtual_space()->committed_size();
162 assert(size >= 3 * alignment, "Young space is not large enough for eden + 2 survivors");
163
164 size_t survivor_size = size / InitialSurvivorRatio;
165 survivor_size = align_size_down(survivor_size, alignment);
166 // ... but never less than an alignment
167 survivor_size = MAX2(survivor_size, alignment);
168
169 // Young generation is eden + 2 survivor spaces
170 size_t eden_size = size - (2 * survivor_size);
171
172 // Now go ahead and set 'em.
173 set_space_boundaries(eden_size, survivor_size);
174 space_invariants();
175
176 if (UsePerfData) {
177 _eden_counters->update_capacity();
178 _from_counters->update_capacity();
179 _to_counters->update_capacity();
180 }
181 }
182
183 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
184 assert(eden_size < virtual_space()->committed_size(), "just checking");
185 assert(eden_size > 0 && survivor_size > 0, "just checking");
186
187 // Initial layout is Eden, to, from. After swapping survivor spaces,
188 // that leaves us with Eden, from, to, which is step one in our two
189 // step resize-with-live-data procedure.
190 char *eden_start = virtual_space()->low();
191 char *to_start = eden_start + eden_size;
192 char *from_start = to_start + survivor_size;
193 char *from_end = from_start + survivor_size;
194
195 assert(from_end == virtual_space()->high(), "just checking");
196 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
197 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
198 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
199
200 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
201 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
202 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
203
204 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
205 to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
206 from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
207 }
208
209 #ifndef PRODUCT
210 void PSYoungGen::space_invariants() {
211 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
212 const size_t alignment = heap->space_alignment();
213
214 // Currently, our eden size cannot shrink to zero
215 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
216 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
217 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
218
219 // Relationship of spaces to each other
220 char* eden_start = (char*)eden_space()->bottom();
221 char* eden_end = (char*)eden_space()->end();
222 char* from_start = (char*)from_space()->bottom();
223 char* from_end = (char*)from_space()->end();
224 char* to_start = (char*)to_space()->bottom();
225 char* to_end = (char*)to_space()->end();
226
227 guarantee(eden_start >= virtual_space()->low(), "eden bottom");
228 guarantee(eden_start < eden_end, "eden space consistency");
229 guarantee(from_start < from_end, "from space consistency");
230 guarantee(to_start < to_end, "to space consistency");
231
232 // Check whether from space is below to space
233 if (from_start < to_start) {
234 // Eden, from, to
235 guarantee(eden_end <= from_start, "eden/from boundary");
236 guarantee(from_end <= to_start, "from/to boundary");
237 guarantee(to_end <= virtual_space()->high(), "to end");
238 } else {
239 // Eden, to, from
240 guarantee(eden_end <= to_start, "eden/to boundary");
241 guarantee(to_end <= from_start, "to/from boundary");
242 guarantee(from_end <= virtual_space()->high(), "from end");
243 }
244
245 // More checks that the virtual space is consistent with the spaces
246 assert(virtual_space()->committed_size() >=
247 (eden_space()->capacity_in_bytes() +
248 to_space()->capacity_in_bytes() +
249 from_space()->capacity_in_bytes()), "Committed size is inconsistent");
250 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
251 "Space invariant");
252 char* eden_top = (char*)eden_space()->top();
253 char* from_top = (char*)from_space()->top();
254 char* to_top = (char*)to_space()->top();
255 assert(eden_top <= virtual_space()->high(), "eden top");
256 assert(from_top <= virtual_space()->high(), "from top");
257 assert(to_top <= virtual_space()->high(), "to top");
258
259 virtual_space()->verify();
260 }
261 #endif
262
263 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
264 // Resize the generation if needed. If the generation resize
265 // reports false, do not attempt to resize the spaces.
266 if (resize_generation(eden_size, survivor_size)) {
267 // Then we lay out the spaces inside the generation
268 resize_spaces(eden_size, survivor_size);
269
270 space_invariants();
271
272 if (PrintAdaptiveSizePolicy && Verbose) {
273 gclog_or_tty->print_cr("Young generation size: "
274 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
275 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
276 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
277 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
278 _max_gen_size, min_gen_size());
279 }
280 }
281 }
282
283
284 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
285 const size_t alignment = virtual_space()->alignment();
286 size_t orig_size = virtual_space()->committed_size();
287 bool size_changed = false;
288
289 // There used to be this guarantee there.
290 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
291 // Code below forces this requirement. In addition the desired eden
292 // size and desired survivor sizes are desired goals and may
293 // exceed the total generation size.
294
295 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
296
297 // Adjust new generation size
298 const size_t eden_plus_survivors =
299 align_size_up(eden_size + 2 * survivor_size, alignment);
300 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
301 min_gen_size());
302 assert(desired_size <= max_size(), "just checking");
303
304 if (desired_size > orig_size) {
305 // Grow the generation
306 size_t change = desired_size - orig_size;
307 assert(change % alignment == 0, "just checking");
308 HeapWord* prev_high = (HeapWord*) virtual_space()->high();
309 if (!virtual_space()->expand_by(change)) {
310 return false; // Error if we fail to resize!
311 }
312 if (ZapUnusedHeapArea) {
313 // Mangle newly committed space immediately because it
314 // can be done here more simply that after the new
315 // spaces have been computed.
316 HeapWord* new_high = (HeapWord*) virtual_space()->high();
317 MemRegion mangle_region(prev_high, new_high);
318 SpaceMangler::mangle_region(mangle_region);
319 }
320 size_changed = true;
321 } else if (desired_size < orig_size) {
322 size_t desired_change = orig_size - desired_size;
323 assert(desired_change % alignment == 0, "just checking");
324
325 desired_change = limit_gen_shrink(desired_change);
326
327 if (desired_change > 0) {
328 virtual_space()->shrink_by(desired_change);
329 reset_survivors_after_shrink();
330
331 size_changed = true;
332 }
333 } else {
334 if (Verbose && PrintGC) {
335 if (orig_size == gen_size_limit()) {
336 gclog_or_tty->print_cr("PSYoung generation size at maximum: "
337 SIZE_FORMAT "K", orig_size/K);
338 } else if (orig_size == min_gen_size()) {
339 gclog_or_tty->print_cr("PSYoung generation size at minium: "
340 SIZE_FORMAT "K", orig_size/K);
341 }
342 }
343 }
344
345 if (size_changed) {
346 post_resize();
347
348 if (Verbose && PrintGC) {
349 size_t current_size = virtual_space()->committed_size();
350 gclog_or_tty->print_cr("PSYoung generation size changed: "
351 SIZE_FORMAT "K->" SIZE_FORMAT "K",
352 orig_size/K, current_size/K);
353 }
354 }
355
356 guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
357 virtual_space()->committed_size() == max_size(), "Sanity");
358
359 return true;
360 }
361
362 #ifndef PRODUCT
363 // In the numa case eden is not mangled so a survivor space
364 // moving into a region previously occupied by a survivor
365 // may find an unmangled region. Also in the PS case eden
366 // to-space and from-space may not touch (i.e., there may be
367 // gaps between them due to movement while resizing the
368 // spaces). Those gaps must be mangled.
369 void PSYoungGen::mangle_survivors(MutableSpace* s1,
370 MemRegion s1MR,
371 MutableSpace* s2,
372 MemRegion s2MR) {
373 // Check eden and gap between eden and from-space, in deciding
374 // what to mangle in from-space. Check the gap between from-space
375 // and to-space when deciding what to mangle.
376 //
377 // +--------+ +----+ +---+
378 // | eden | |s1 | |s2 |
379 // +--------+ +----+ +---+
380 // +-------+ +-----+
381 // |s1MR | |s2MR |
382 // +-------+ +-----+
383 // All of survivor-space is properly mangled so find the
384 // upper bound on the mangling for any portion above current s1.
385 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());
386 MemRegion delta1_left;
387 if (s1MR.start() < delta_end) {
388 delta1_left = MemRegion(s1MR.start(), delta_end);
389 s1->mangle_region(delta1_left);
390 }
391 // Find any portion to the right of the current s1.
392 HeapWord* delta_start = MAX2(s1->end(), s1MR.start());
393 MemRegion delta1_right;
394 if (delta_start < s1MR.end()) {
395 delta1_right = MemRegion(delta_start, s1MR.end());
396 s1->mangle_region(delta1_right);
397 }
398
399 // Similarly for the second survivor space except that
400 // any of the new region that overlaps with the current
401 // region of the first survivor space has already been
402 // mangled.
403 delta_end = MIN2(s2->bottom(), s2MR.end());
404 delta_start = MAX2(s2MR.start(), s1->end());
405 MemRegion delta2_left;
406 if (s2MR.start() < delta_end) {
407 delta2_left = MemRegion(s2MR.start(), delta_end);
408 s2->mangle_region(delta2_left);
409 }
410 delta_start = MAX2(s2->end(), s2MR.start());
411 MemRegion delta2_right;
412 if (delta_start < s2MR.end()) {
413 s2->mangle_region(delta2_right);
414 }
415
416 if (TraceZapUnusedHeapArea) {
417 // s1
418 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
419 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
420 p2i(s1->bottom()), p2i(s1->end()),
421 p2i(s1MR.start()), p2i(s1MR.end()));
422 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
423 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
424 p2i(delta1_left.start()), p2i(delta1_left.end()),
425 p2i(delta1_right.start()), p2i(delta1_right.end()));
426
427 // s2
428 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
429 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
430 p2i(s2->bottom()), p2i(s2->end()),
431 p2i(s2MR.start()), p2i(s2MR.end()));
432 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
433 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
434 p2i(delta2_left.start()), p2i(delta2_left.end()),
435 p2i(delta2_right.start()), p2i(delta2_right.end()));
436 }
437
438 }
439 #endif // NOT PRODUCT
440
441 void PSYoungGen::resize_spaces(size_t requested_eden_size,
442 size_t requested_survivor_size) {
443 assert(UseAdaptiveSizePolicy, "sanity check");
444 assert(requested_eden_size > 0 && requested_survivor_size > 0,
445 "just checking");
446
447 // We require eden and to space to be empty
448 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
449 return;
450 }
451
452 if (PrintAdaptiveSizePolicy && Verbose) {
453 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
454 SIZE_FORMAT
455 ", requested_survivor_size: " SIZE_FORMAT ")",
456 requested_eden_size, requested_survivor_size);
457 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
458 SIZE_FORMAT,
459 p2i(eden_space()->bottom()),
460 p2i(eden_space()->end()),
461 pointer_delta(eden_space()->end(),
462 eden_space()->bottom(),
463 sizeof(char)));
464 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") "
465 SIZE_FORMAT,
466 p2i(from_space()->bottom()),
467 p2i(from_space()->end()),
468 pointer_delta(from_space()->end(),
469 from_space()->bottom(),
470 sizeof(char)));
471 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") "
472 SIZE_FORMAT,
473 p2i(to_space()->bottom()),
474 p2i(to_space()->end()),
475 pointer_delta( to_space()->end(),
476 to_space()->bottom(),
477 sizeof(char)));
478 }
479
480 // There's nothing to do if the new sizes are the same as the current
481 if (requested_survivor_size == to_space()->capacity_in_bytes() &&
482 requested_survivor_size == from_space()->capacity_in_bytes() &&
483 requested_eden_size == eden_space()->capacity_in_bytes()) {
484 if (PrintAdaptiveSizePolicy && Verbose) {
485 gclog_or_tty->print_cr(" capacities are the right sizes, returning");
486 }
487 return;
488 }
489
490 char* eden_start = (char*)eden_space()->bottom();
491 char* eden_end = (char*)eden_space()->end();
492 char* from_start = (char*)from_space()->bottom();
493 char* from_end = (char*)from_space()->end();
494 char* to_start = (char*)to_space()->bottom();
495 char* to_end = (char*)to_space()->end();
496
497 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
498 const size_t alignment = heap->space_alignment();
499 const bool maintain_minimum =
500 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
501
502 bool eden_from_to_order = from_start < to_start;
503 // Check whether from space is below to space
504 if (eden_from_to_order) {
505 // Eden, from, to
506 eden_from_to_order = true;
507 if (PrintAdaptiveSizePolicy && Verbose) {
508 gclog_or_tty->print_cr(" Eden, from, to:");
509 }
510
511 // Set eden
512 // "requested_eden_size" is a goal for the size of eden
513 // and may not be attainable. "eden_size" below is
514 // calculated based on the location of from-space and
515 // the goal for the size of eden. from-space is
516 // fixed in place because it contains live data.
517 // The calculation is done this way to avoid 32bit
518 // overflow (i.e., eden_start + requested_eden_size
519 // may too large for representation in 32bits).
520 size_t eden_size;
521 if (maintain_minimum) {
522 // Only make eden larger than the requested size if
523 // the minimum size of the generation has to be maintained.
524 // This could be done in general but policy at a higher
525 // level is determining a requested size for eden and that
526 // should be honored unless there is a fundamental reason.
527 eden_size = pointer_delta(from_start,
528 eden_start,
529 sizeof(char));
530 } else {
531 eden_size = MIN2(requested_eden_size,
532 pointer_delta(from_start, eden_start, sizeof(char)));
533 }
534
535 eden_end = eden_start + eden_size;
536 assert(eden_end >= eden_start, "addition overflowed");
537
538 // To may resize into from space as long as it is clear of live data.
539 // From space must remain page aligned, though, so we need to do some
540 // extra calculations.
541
542 // First calculate an optimal to-space
543 to_end = (char*)virtual_space()->high();
544 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
545 sizeof(char));
546
547 // Does the optimal to-space overlap from-space?
548 if (to_start < (char*)from_space()->end()) {
549 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
550
551 // Calculate the minimum offset possible for from_end
552 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));
553
554 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
555 if (from_size == 0) {
556 from_size = alignment;
557 } else {
558 from_size = align_size_up(from_size, alignment);
559 }
560
561 from_end = from_start + from_size;
562 assert(from_end > from_start, "addition overflow or from_size problem");
563
564 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");
565
566 // Now update to_start with the new from_end
567 to_start = MAX2(from_end, to_start);
568 }
569
570 guarantee(to_start != to_end, "to space is zero sized");
571
572 if (PrintAdaptiveSizePolicy && Verbose) {
573 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
574 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
575 p2i(eden_start),
576 p2i(eden_end),
577 pointer_delta(eden_end, eden_start, sizeof(char)));
578 gclog_or_tty->print_cr(" [from_start .. from_end): "
579 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
580 p2i(from_start),
581 p2i(from_end),
582 pointer_delta(from_end, from_start, sizeof(char)));
583 gclog_or_tty->print_cr(" [ to_start .. to_end): "
584 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
585 p2i(to_start),
586 p2i(to_end),
587 pointer_delta( to_end, to_start, sizeof(char)));
588 }
589 } else {
590 // Eden, to, from
591 if (PrintAdaptiveSizePolicy && Verbose) {
592 gclog_or_tty->print_cr(" Eden, to, from:");
593 }
594
595 // To space gets priority over eden resizing. Note that we position
596 // to space as if we were able to resize from space, even though from
597 // space is not modified.
598 // Giving eden priority was tried and gave poorer performance.
599 to_end = (char*)pointer_delta(virtual_space()->high(),
600 (char*)requested_survivor_size,
601 sizeof(char));
602 to_end = MIN2(to_end, from_start);
603 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
604 sizeof(char));
605 // if the space sizes are to be increased by several times then
606 // 'to_start' will point beyond the young generation. In this case
607 // 'to_start' should be adjusted.
608 to_start = MAX2(to_start, eden_start + alignment);
609
610 // Compute how big eden can be, then adjust end.
611 // See comments above on calculating eden_end.
612 size_t eden_size;
613 if (maintain_minimum) {
614 eden_size = pointer_delta(to_start, eden_start, sizeof(char));
615 } else {
616 eden_size = MIN2(requested_eden_size,
617 pointer_delta(to_start, eden_start, sizeof(char)));
618 }
619 eden_end = eden_start + eden_size;
620 assert(eden_end >= eden_start, "addition overflowed");
621
622 // Could choose to not let eden shrink
623 // to_start = MAX2(to_start, eden_end);
624
625 // Don't let eden shrink down to 0 or less.
626 eden_end = MAX2(eden_end, eden_start + alignment);
627 to_start = MAX2(to_start, eden_end);
628
629 if (PrintAdaptiveSizePolicy && Verbose) {
630 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
631 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
632 p2i(eden_start),
633 p2i(eden_end),
634 pointer_delta(eden_end, eden_start, sizeof(char)));
635 gclog_or_tty->print_cr(" [ to_start .. to_end): "
636 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
637 p2i(to_start),
638 p2i(to_end),
639 pointer_delta( to_end, to_start, sizeof(char)));
640 gclog_or_tty->print_cr(" [from_start .. from_end): "
641 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
642 p2i(from_start),
643 p2i(from_end),
644 pointer_delta(from_end, from_start, sizeof(char)));
645 }
646 }
647
648
649 guarantee((HeapWord*)from_start <= from_space()->bottom(),
650 "from start moved to the right");
651 guarantee((HeapWord*)from_end >= from_space()->top(),
652 "from end moved into live data");
653 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
654 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
655 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
656
657 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
658 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
659 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
660
661 // Let's make sure the call to initialize doesn't reset "top"!
662 HeapWord* old_from_top = from_space()->top();
663
664 // For PrintAdaptiveSizePolicy block below
665 size_t old_from = from_space()->capacity_in_bytes();
666 size_t old_to = to_space()->capacity_in_bytes();
667
668 if (ZapUnusedHeapArea) {
669 // NUMA is a special case because a numa space is not mangled
670 // in order to not prematurely bind its address to memory to
671 // the wrong memory (i.e., don't want the GC thread to first
672 // touch the memory). The survivor spaces are not numa
673 // spaces and are mangled.
674 if (UseNUMA) {
675 if (eden_from_to_order) {
676 mangle_survivors(from_space(), fromMR, to_space(), toMR);
677 } else {
678 mangle_survivors(to_space(), toMR, from_space(), fromMR);
679 }
680 }
681
682 // If not mangling the spaces, do some checking to verify that
683 // the spaces are already mangled.
684 // The spaces should be correctly mangled at this point so
685 // do some checking here. Note that they are not being mangled
686 // in the calls to initialize().
687 // Must check mangling before the spaces are reshaped. Otherwise,
688 // the bottom or end of one space may have moved into an area
689 // covered by another space and a failure of the check may
690 // not correctly indicate which space is not properly mangled.
691 HeapWord* limit = (HeapWord*) virtual_space()->high();
692 eden_space()->check_mangled_unused_area(limit);
693 from_space()->check_mangled_unused_area(limit);
694 to_space()->check_mangled_unused_area(limit);
695 }
696 // When an existing space is being initialized, it is not
697 // mangled because the space has been previously mangled.
698 eden_space()->initialize(edenMR,
699 SpaceDecorator::Clear,
700 SpaceDecorator::DontMangle);
701 to_space()->initialize(toMR,
702 SpaceDecorator::Clear,
703 SpaceDecorator::DontMangle);
704 from_space()->initialize(fromMR,
705 SpaceDecorator::DontClear,
706 SpaceDecorator::DontMangle);
707
708 assert(from_space()->top() == old_from_top, "from top changed!");
709
710 if (PrintAdaptiveSizePolicy) {
711 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
712 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
713
714 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
715 "collection: %d "
716 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
717 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
718 heap->total_collections(),
719 old_from, old_to,
720 from_space()->capacity_in_bytes(),
721 to_space()->capacity_in_bytes());
722 gclog_or_tty->cr();
723 }
724 }
725
726 void PSYoungGen::swap_spaces() {
727 MutableSpace* s = from_space();
728 _from_space = to_space();
729 _to_space = s;
730
731 // Now update the decorators.
732 PSMarkSweepDecorator* md = from_mark_sweep();
733 _from_mark_sweep = to_mark_sweep();
734 _to_mark_sweep = md;
735
736 assert(from_mark_sweep()->space() == from_space(), "Sanity");
737 assert(to_mark_sweep()->space() == to_space(), "Sanity");
738 }
739
740 size_t PSYoungGen::capacity_in_bytes() const {
741 return eden_space()->capacity_in_bytes()
742 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
743 }
744
745
746 size_t PSYoungGen::used_in_bytes() const {
747 return eden_space()->used_in_bytes()
748 + from_space()->used_in_bytes(); // to_space() is only used during scavenge
749 }
750
751
752 size_t PSYoungGen::free_in_bytes() const {
753 return eden_space()->free_in_bytes()
754 + from_space()->free_in_bytes(); // to_space() is only used during scavenge
755 }
756
757 size_t PSYoungGen::capacity_in_words() const {
758 return eden_space()->capacity_in_words()
759 + from_space()->capacity_in_words(); // to_space() is only used during scavenge
760 }
761
762
763 size_t PSYoungGen::used_in_words() const {
764 return eden_space()->used_in_words()
765 + from_space()->used_in_words(); // to_space() is only used during scavenge
766 }
767
768
769 size_t PSYoungGen::free_in_words() const {
770 return eden_space()->free_in_words()
771 + from_space()->free_in_words(); // to_space() is only used during scavenge
772 }
773
774 void PSYoungGen::object_iterate(ObjectClosure* blk) {
775 eden_space()->object_iterate(blk);
776 from_space()->object_iterate(blk);
777 to_space()->object_iterate(blk);
778 }
779
780 void PSYoungGen::precompact() {
781 eden_mark_sweep()->precompact();
782 from_mark_sweep()->precompact();
783 to_mark_sweep()->precompact();
784 }
785
786 void PSYoungGen::adjust_pointers() {
787 eden_mark_sweep()->adjust_pointers();
788 from_mark_sweep()->adjust_pointers();
789 to_mark_sweep()->adjust_pointers();
790 }
791
792 void PSYoungGen::compact() {
793 eden_mark_sweep()->compact(ZapUnusedHeapArea);
794 from_mark_sweep()->compact(ZapUnusedHeapArea);
795 // Mark sweep stores preserved markOops in to space, don't disturb!
796 to_mark_sweep()->compact(false);
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 // Note that a space is not printed before the [NAME:
816 void PSYoungGen::print_used_change(size_t prev_used) const {
817 gclog_or_tty->print("[%s:", name());
818 gclog_or_tty->print(" " SIZE_FORMAT "K"
819 "->" SIZE_FORMAT "K"
820 "(" SIZE_FORMAT "K)",
821 prev_used / K, used_in_bytes() / K,
822 capacity_in_bytes() / K);
823 gclog_or_tty->print("]");
824 }
825
826 size_t PSYoungGen::available_for_expansion() {
827 ShouldNotReachHere();
828 return 0;
829 }
830
831 size_t PSYoungGen::available_for_contraction() {
832 ShouldNotReachHere();
833 return 0;
834 }
835
836 size_t PSYoungGen::available_to_min_gen() {
837 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
838 return virtual_space()->committed_size() - min_gen_size();
839 }
840
841 // This method assumes that from-space has live data and that
842 // any shrinkage of the young gen is limited by location of
843 // from-space.
844 size_t PSYoungGen::available_to_live() {
845 size_t delta_in_survivor = 0;
846 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
847 const size_t space_alignment = heap->space_alignment();
848 const size_t gen_alignment = heap->generation_alignment();
849
850 MutableSpace* space_shrinking = NULL;
851 if (from_space()->end() > to_space()->end()) {
852 space_shrinking = from_space();
853 } else {
854 space_shrinking = to_space();
855 }
856
857 // Include any space that is committed but not included in
858 // the survivor spaces.
859 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
860 "Survivor space beyond high end");
861 size_t unused_committed = pointer_delta(virtual_space()->high(),
862 space_shrinking->end(), sizeof(char));
863
864 if (space_shrinking->is_empty()) {
865 // Don't let the space shrink to 0
866 assert(space_shrinking->capacity_in_bytes() >= space_alignment,
867 "Space is too small");
868 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
869 } else {
870 delta_in_survivor = pointer_delta(space_shrinking->end(),
871 space_shrinking->top(),
872 sizeof(char));
873 }
874
875 size_t delta_in_bytes = unused_committed + delta_in_survivor;
876 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
877 return delta_in_bytes;
878 }
879
880 // Return the number of bytes available for resizing down the young
881 // generation. This is the minimum of
882 // input "bytes"
883 // bytes to the minimum young gen size
884 // bytes to the size currently being used + some small extra
885 size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
886 // Allow shrinkage into the current eden but keep eden large enough
887 // to maintain the minimum young gen size
888 bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
889 return align_size_down(bytes, virtual_space()->alignment());
890 }
891
892 void PSYoungGen::reset_after_change() {
893 ShouldNotReachHere();
894 }
895
896 void PSYoungGen::reset_survivors_after_shrink() {
897 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
898 (HeapWord*)virtual_space()->high_boundary());
899 PSScavenge::reference_processor()->set_span(_reserved);
900
901 MutableSpace* space_shrinking = NULL;
902 if (from_space()->end() > to_space()->end()) {
903 space_shrinking = from_space();
904 } else {
905 space_shrinking = to_space();
906 }
907
908 HeapWord* new_end = (HeapWord*)virtual_space()->high();
909 assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
910 // Was there a shrink of the survivor space?
911 if (new_end < space_shrinking->end()) {
912 MemRegion mr(space_shrinking->bottom(), new_end);
913 space_shrinking->initialize(mr,
914 SpaceDecorator::DontClear,
915 SpaceDecorator::Mangle);
916 }
917 }
918
919 // This method currently does not expect to expand into eden (i.e.,
920 // the virtual space boundaries is expected to be consistent
921 // with the eden boundaries..
922 void PSYoungGen::post_resize() {
923 assert_locked_or_safepoint(Heap_lock);
924 assert((eden_space()->bottom() < to_space()->bottom()) &&
925 (eden_space()->bottom() < from_space()->bottom()),
926 "Eden is assumed to be below the survivor spaces");
927
928 MemRegion cmr((HeapWord*)virtual_space()->low(),
929 (HeapWord*)virtual_space()->high());
930 Universe::heap()->barrier_set()->resize_covered_region(cmr);
931 space_invariants();
932 }
933
934
935
936 void PSYoungGen::update_counters() {
937 if (UsePerfData) {
938 _eden_counters->update_all();
939 _from_counters->update_all();
940 _to_counters->update_all();
941 _gen_counters->update_all();
942 }
943 }
944
945 void PSYoungGen::verify() {
946 eden_space()->verify();
947 from_space()->verify();
948 to_space()->verify();
949 }
950
951 #ifndef PRODUCT
952 void PSYoungGen::record_spaces_top() {
953 assert(ZapUnusedHeapArea, "Not mangling unused space");
954 eden_space()->set_top_for_allocations();
955 from_space()->set_top_for_allocations();
956 to_space()->set_top_for_allocations();
957 }
958 #endif