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