Thu, 14 Mar 2013 09:37:38 +0100
6733980: par compact - TraceGen1Time always shows 0.0000 seconds
Summary: Use the correct collector to retrieve accumulated gen1 trace time
Reviewed-by: johnc, jmasa
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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"
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 {}
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 }
53 void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
54 initialize_virtual_space(rs, alignment);
55 initialize_work();
56 }
58 void PSYoungGen::initialize_work() {
60 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
61 (HeapWord*)virtual_space()->high_boundary());
63 MemRegion cmr((HeapWord*)virtual_space()->low(),
64 (HeapWord*)virtual_space()->high());
65 Universe::heap()->barrier_set()->resize_covered_region(cmr);
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 }
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());
82 if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
83 vm_exit_during_initialization("Could not allocate a young gen space");
84 }
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);
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 }
101 // Generation Counters - generation 0, 3 subspaces
102 _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);
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();
109 size_t max_survivor_size;
110 size_t max_eden_size;
112 if (UseAdaptiveSizePolicy) {
113 max_survivor_size = size / MinSurvivorRatio;
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);
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;
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);
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 reachs 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 }
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);
151 compute_initial_space_boundaries();
152 }
154 void PSYoungGen::compute_initial_space_boundaries() {
155 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
156 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
158 // Compute sizes
159 size_t alignment = heap->intra_heap_alignment();
160 size_t size = virtual_space()->committed_size();
162 size_t survivor_size = size / InitialSurvivorRatio;
163 survivor_size = align_size_down(survivor_size, alignment);
164 // ... but never less than an alignment
165 survivor_size = MAX2(survivor_size, alignment);
167 // Young generation is eden + 2 survivor spaces
168 size_t eden_size = size - (2 * survivor_size);
170 // Now go ahead and set 'em.
171 set_space_boundaries(eden_size, survivor_size);
172 space_invariants();
174 if (UsePerfData) {
175 _eden_counters->update_capacity();
176 _from_counters->update_capacity();
177 _to_counters->update_capacity();
178 }
179 }
181 void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
182 assert(eden_size < virtual_space()->committed_size(), "just checking");
183 assert(eden_size > 0 && survivor_size > 0, "just checking");
185 // Initial layout is Eden, to, from. After swapping survivor spaces,
186 // that leaves us with Eden, from, to, which is step one in our two
187 // step resize-with-live-data procedure.
188 char *eden_start = virtual_space()->low();
189 char *to_start = eden_start + eden_size;
190 char *from_start = to_start + survivor_size;
191 char *from_end = from_start + survivor_size;
193 assert(from_end == virtual_space()->high(), "just checking");
194 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
195 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
196 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
198 MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
199 MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
200 MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
202 eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
203 to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
204 from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
205 }
207 #ifndef PRODUCT
208 void PSYoungGen::space_invariants() {
209 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
210 const size_t alignment = heap->intra_heap_alignment();
212 // Currently, our eden size cannot shrink to zero
213 guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
214 guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
215 guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
217 // Relationship of spaces to each other
218 char* eden_start = (char*)eden_space()->bottom();
219 char* eden_end = (char*)eden_space()->end();
220 char* from_start = (char*)from_space()->bottom();
221 char* from_end = (char*)from_space()->end();
222 char* to_start = (char*)to_space()->bottom();
223 char* to_end = (char*)to_space()->end();
225 guarantee(eden_start >= virtual_space()->low(), "eden bottom");
226 guarantee(eden_start < eden_end, "eden space consistency");
227 guarantee(from_start < from_end, "from space consistency");
228 guarantee(to_start < to_end, "to space consistency");
230 // Check whether from space is below to space
231 if (from_start < to_start) {
232 // Eden, from, to
233 guarantee(eden_end <= from_start, "eden/from boundary");
234 guarantee(from_end <= to_start, "from/to boundary");
235 guarantee(to_end <= virtual_space()->high(), "to end");
236 } else {
237 // Eden, to, from
238 guarantee(eden_end <= to_start, "eden/to boundary");
239 guarantee(to_end <= from_start, "to/from boundary");
240 guarantee(from_end <= virtual_space()->high(), "from end");
241 }
243 // More checks that the virtual space is consistent with the spaces
244 assert(virtual_space()->committed_size() >=
245 (eden_space()->capacity_in_bytes() +
246 to_space()->capacity_in_bytes() +
247 from_space()->capacity_in_bytes()), "Committed size is inconsistent");
248 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
249 "Space invariant");
250 char* eden_top = (char*)eden_space()->top();
251 char* from_top = (char*)from_space()->top();
252 char* to_top = (char*)to_space()->top();
253 assert(eden_top <= virtual_space()->high(), "eden top");
254 assert(from_top <= virtual_space()->high(), "from top");
255 assert(to_top <= virtual_space()->high(), "to top");
257 virtual_space()->verify();
258 }
259 #endif
261 void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
262 // Resize the generation if needed. If the generation resize
263 // reports false, do not attempt to resize the spaces.
264 if (resize_generation(eden_size, survivor_size)) {
265 // Then we lay out the spaces inside the generation
266 resize_spaces(eden_size, survivor_size);
268 space_invariants();
270 if (PrintAdaptiveSizePolicy && Verbose) {
271 gclog_or_tty->print_cr("Young generation size: "
272 "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
273 " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
274 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
275 eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
276 _max_gen_size, min_gen_size());
277 }
278 }
279 }
282 bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
283 const size_t alignment = virtual_space()->alignment();
284 size_t orig_size = virtual_space()->committed_size();
285 bool size_changed = false;
287 // There used to be this guarantee there.
288 // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
289 // Code below forces this requirement. In addition the desired eden
290 // size and disired survivor sizes are desired goals and may
291 // exceed the total generation size.
293 assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
295 // Adjust new generation size
296 const size_t eden_plus_survivors =
297 align_size_up(eden_size + 2 * survivor_size, alignment);
298 size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
299 min_gen_size());
300 assert(desired_size <= max_size(), "just checking");
302 if (desired_size > orig_size) {
303 // Grow the generation
304 size_t change = desired_size - orig_size;
305 assert(change % alignment == 0, "just checking");
306 HeapWord* prev_high = (HeapWord*) virtual_space()->high();
307 if (!virtual_space()->expand_by(change)) {
308 return false; // Error if we fail to resize!
309 }
310 if (ZapUnusedHeapArea) {
311 // Mangle newly committed space immediately because it
312 // can be done here more simply that after the new
313 // spaces have been computed.
314 HeapWord* new_high = (HeapWord*) virtual_space()->high();
315 MemRegion mangle_region(prev_high, new_high);
316 SpaceMangler::mangle_region(mangle_region);
317 }
318 size_changed = true;
319 } else if (desired_size < orig_size) {
320 size_t desired_change = orig_size - desired_size;
321 assert(desired_change % alignment == 0, "just checking");
323 desired_change = limit_gen_shrink(desired_change);
325 if (desired_change > 0) {
326 virtual_space()->shrink_by(desired_change);
327 reset_survivors_after_shrink();
329 size_changed = true;
330 }
331 } else {
332 if (Verbose && PrintGC) {
333 if (orig_size == gen_size_limit()) {
334 gclog_or_tty->print_cr("PSYoung generation size at maximum: "
335 SIZE_FORMAT "K", orig_size/K);
336 } else if (orig_size == min_gen_size()) {
337 gclog_or_tty->print_cr("PSYoung generation size at minium: "
338 SIZE_FORMAT "K", orig_size/K);
339 }
340 }
341 }
343 if (size_changed) {
344 post_resize();
346 if (Verbose && PrintGC) {
347 size_t current_size = virtual_space()->committed_size();
348 gclog_or_tty->print_cr("PSYoung generation size changed: "
349 SIZE_FORMAT "K->" SIZE_FORMAT "K",
350 orig_size/K, current_size/K);
351 }
352 }
354 guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
355 virtual_space()->committed_size() == max_size(), "Sanity");
357 return true;
358 }
360 #ifndef PRODUCT
361 // In the numa case eden is not mangled so a survivor space
362 // moving into a region previously occupied by a survivor
363 // may find an unmangled region. Also in the PS case eden
364 // to-space and from-space may not touch (i.e., there may be
365 // gaps between them due to movement while resizing the
366 // spaces). Those gaps must be mangled.
367 void PSYoungGen::mangle_survivors(MutableSpace* s1,
368 MemRegion s1MR,
369 MutableSpace* s2,
370 MemRegion s2MR) {
371 // Check eden and gap between eden and from-space, in deciding
372 // what to mangle in from-space. Check the gap between from-space
373 // and to-space when deciding what to mangle.
374 //
375 // +--------+ +----+ +---+
376 // | eden | |s1 | |s2 |
377 // +--------+ +----+ +---+
378 // +-------+ +-----+
379 // |s1MR | |s2MR |
380 // +-------+ +-----+
381 // All of survivor-space is properly mangled so find the
382 // upper bound on the mangling for any portion above current s1.
383 HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());
384 MemRegion delta1_left;
385 if (s1MR.start() < delta_end) {
386 delta1_left = MemRegion(s1MR.start(), delta_end);
387 s1->mangle_region(delta1_left);
388 }
389 // Find any portion to the right of the current s1.
390 HeapWord* delta_start = MAX2(s1->end(), s1MR.start());
391 MemRegion delta1_right;
392 if (delta_start < s1MR.end()) {
393 delta1_right = MemRegion(delta_start, s1MR.end());
394 s1->mangle_region(delta1_right);
395 }
397 // Similarly for the second survivor space except that
398 // any of the new region that overlaps with the current
399 // region of the first survivor space has already been
400 // mangled.
401 delta_end = MIN2(s2->bottom(), s2MR.end());
402 delta_start = MAX2(s2MR.start(), s1->end());
403 MemRegion delta2_left;
404 if (s2MR.start() < delta_end) {
405 delta2_left = MemRegion(s2MR.start(), delta_end);
406 s2->mangle_region(delta2_left);
407 }
408 delta_start = MAX2(s2->end(), s2MR.start());
409 MemRegion delta2_right;
410 if (delta_start < s2MR.end()) {
411 s2->mangle_region(delta2_right);
412 }
414 if (TraceZapUnusedHeapArea) {
415 // s1
416 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
417 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
418 s1->bottom(), s1->end(), s1MR.start(), s1MR.end());
419 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
420 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
421 delta1_left.start(), delta1_left.end(), delta1_right.start(),
422 delta1_right.end());
424 // s2
425 gclog_or_tty->print_cr("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
426 "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
427 s2->bottom(), s2->end(), s2MR.start(), s2MR.end());
428 gclog_or_tty->print_cr(" Mangle before: [" PTR_FORMAT ", "
429 PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
430 delta2_left.start(), delta2_left.end(), delta2_right.start(),
431 delta2_right.end());
432 }
434 }
435 #endif // NOT PRODUCT
437 void PSYoungGen::resize_spaces(size_t requested_eden_size,
438 size_t requested_survivor_size) {
439 assert(UseAdaptiveSizePolicy, "sanity check");
440 assert(requested_eden_size > 0 && requested_survivor_size > 0,
441 "just checking");
443 // We require eden and to space to be empty
444 if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
445 return;
446 }
448 if (PrintAdaptiveSizePolicy && Verbose) {
449 gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
450 SIZE_FORMAT
451 ", requested_survivor_size: " SIZE_FORMAT ")",
452 requested_eden_size, requested_survivor_size);
453 gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
454 SIZE_FORMAT,
455 eden_space()->bottom(),
456 eden_space()->end(),
457 pointer_delta(eden_space()->end(),
458 eden_space()->bottom(),
459 sizeof(char)));
460 gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") "
461 SIZE_FORMAT,
462 from_space()->bottom(),
463 from_space()->end(),
464 pointer_delta(from_space()->end(),
465 from_space()->bottom(),
466 sizeof(char)));
467 gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") "
468 SIZE_FORMAT,
469 to_space()->bottom(),
470 to_space()->end(),
471 pointer_delta( to_space()->end(),
472 to_space()->bottom(),
473 sizeof(char)));
474 }
476 // There's nothing to do if the new sizes are the same as the current
477 if (requested_survivor_size == to_space()->capacity_in_bytes() &&
478 requested_survivor_size == from_space()->capacity_in_bytes() &&
479 requested_eden_size == eden_space()->capacity_in_bytes()) {
480 if (PrintAdaptiveSizePolicy && Verbose) {
481 gclog_or_tty->print_cr(" capacities are the right sizes, returning");
482 }
483 return;
484 }
486 char* eden_start = (char*)eden_space()->bottom();
487 char* eden_end = (char*)eden_space()->end();
488 char* from_start = (char*)from_space()->bottom();
489 char* from_end = (char*)from_space()->end();
490 char* to_start = (char*)to_space()->bottom();
491 char* to_end = (char*)to_space()->end();
493 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
494 const size_t alignment = heap->intra_heap_alignment();
495 const bool maintain_minimum =
496 (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
498 bool eden_from_to_order = from_start < to_start;
499 // Check whether from space is below to space
500 if (eden_from_to_order) {
501 // Eden, from, to
502 eden_from_to_order = true;
503 if (PrintAdaptiveSizePolicy && Verbose) {
504 gclog_or_tty->print_cr(" Eden, from, to:");
505 }
507 // Set eden
508 // "requested_eden_size" is a goal for the size of eden
509 // and may not be attainable. "eden_size" below is
510 // calculated based on the location of from-space and
511 // the goal for the size of eden. from-space is
512 // fixed in place because it contains live data.
513 // The calculation is done this way to avoid 32bit
514 // overflow (i.e., eden_start + requested_eden_size
515 // may too large for representation in 32bits).
516 size_t eden_size;
517 if (maintain_minimum) {
518 // Only make eden larger than the requested size if
519 // the minimum size of the generation has to be maintained.
520 // This could be done in general but policy at a higher
521 // level is determining a requested size for eden and that
522 // should be honored unless there is a fundamental reason.
523 eden_size = pointer_delta(from_start,
524 eden_start,
525 sizeof(char));
526 } else {
527 eden_size = MIN2(requested_eden_size,
528 pointer_delta(from_start, eden_start, sizeof(char)));
529 }
531 eden_end = eden_start + eden_size;
532 assert(eden_end >= eden_start, "addition overflowed");
534 // To may resize into from space as long as it is clear of live data.
535 // From space must remain page aligned, though, so we need to do some
536 // extra calculations.
538 // First calculate an optimal to-space
539 to_end = (char*)virtual_space()->high();
540 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
541 sizeof(char));
543 // Does the optimal to-space overlap from-space?
544 if (to_start < (char*)from_space()->end()) {
545 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
547 // Calculate the minimum offset possible for from_end
548 size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));
550 // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
551 if (from_size == 0) {
552 from_size = alignment;
553 } else {
554 from_size = align_size_up(from_size, alignment);
555 }
557 from_end = from_start + from_size;
558 assert(from_end > from_start, "addition overflow or from_size problem");
560 guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");
562 // Now update to_start with the new from_end
563 to_start = MAX2(from_end, to_start);
564 }
566 guarantee(to_start != to_end, "to space is zero sized");
568 if (PrintAdaptiveSizePolicy && Verbose) {
569 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
570 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
571 eden_start,
572 eden_end,
573 pointer_delta(eden_end, eden_start, sizeof(char)));
574 gclog_or_tty->print_cr(" [from_start .. from_end): "
575 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
576 from_start,
577 from_end,
578 pointer_delta(from_end, from_start, sizeof(char)));
579 gclog_or_tty->print_cr(" [ to_start .. to_end): "
580 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
581 to_start,
582 to_end,
583 pointer_delta( to_end, to_start, sizeof(char)));
584 }
585 } else {
586 // Eden, to, from
587 if (PrintAdaptiveSizePolicy && Verbose) {
588 gclog_or_tty->print_cr(" Eden, to, from:");
589 }
591 // To space gets priority over eden resizing. Note that we position
592 // to space as if we were able to resize from space, even though from
593 // space is not modified.
594 // Giving eden priority was tried and gave poorer performance.
595 to_end = (char*)pointer_delta(virtual_space()->high(),
596 (char*)requested_survivor_size,
597 sizeof(char));
598 to_end = MIN2(to_end, from_start);
599 to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
600 sizeof(char));
601 // if the space sizes are to be increased by several times then
602 // 'to_start' will point beyond the young generation. In this case
603 // 'to_start' should be adjusted.
604 to_start = MAX2(to_start, eden_start + alignment);
606 // Compute how big eden can be, then adjust end.
607 // See comments above on calculating eden_end.
608 size_t eden_size;
609 if (maintain_minimum) {
610 eden_size = pointer_delta(to_start, eden_start, sizeof(char));
611 } else {
612 eden_size = MIN2(requested_eden_size,
613 pointer_delta(to_start, eden_start, sizeof(char)));
614 }
615 eden_end = eden_start + eden_size;
616 assert(eden_end >= eden_start, "addition overflowed");
618 // Could choose to not let eden shrink
619 // to_start = MAX2(to_start, eden_end);
621 // Don't let eden shrink down to 0 or less.
622 eden_end = MAX2(eden_end, eden_start + alignment);
623 to_start = MAX2(to_start, eden_end);
625 if (PrintAdaptiveSizePolicy && Verbose) {
626 gclog_or_tty->print_cr(" [eden_start .. eden_end): "
627 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
628 eden_start,
629 eden_end,
630 pointer_delta(eden_end, eden_start, sizeof(char)));
631 gclog_or_tty->print_cr(" [ to_start .. to_end): "
632 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
633 to_start,
634 to_end,
635 pointer_delta( to_end, to_start, sizeof(char)));
636 gclog_or_tty->print_cr(" [from_start .. from_end): "
637 "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
638 from_start,
639 from_end,
640 pointer_delta(from_end, from_start, sizeof(char)));
641 }
642 }
645 guarantee((HeapWord*)from_start <= from_space()->bottom(),
646 "from start moved to the right");
647 guarantee((HeapWord*)from_end >= from_space()->top(),
648 "from end moved into live data");
649 assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
650 assert(is_object_aligned((intptr_t)from_start), "checking alignment");
651 assert(is_object_aligned((intptr_t)to_start), "checking alignment");
653 MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
654 MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end);
655 MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
657 // Let's make sure the call to initialize doesn't reset "top"!
658 HeapWord* old_from_top = from_space()->top();
660 // For PrintAdaptiveSizePolicy block below
661 size_t old_from = from_space()->capacity_in_bytes();
662 size_t old_to = to_space()->capacity_in_bytes();
664 if (ZapUnusedHeapArea) {
665 // NUMA is a special case because a numa space is not mangled
666 // in order to not prematurely bind its address to memory to
667 // the wrong memory (i.e., don't want the GC thread to first
668 // touch the memory). The survivor spaces are not numa
669 // spaces and are mangled.
670 if (UseNUMA) {
671 if (eden_from_to_order) {
672 mangle_survivors(from_space(), fromMR, to_space(), toMR);
673 } else {
674 mangle_survivors(to_space(), toMR, from_space(), fromMR);
675 }
676 }
678 // If not mangling the spaces, do some checking to verify that
679 // the spaces are already mangled.
680 // The spaces should be correctly mangled at this point so
681 // do some checking here. Note that they are not being mangled
682 // in the calls to initialize().
683 // Must check mangling before the spaces are reshaped. Otherwise,
684 // the bottom or end of one space may have moved into an area
685 // covered by another space and a failure of the check may
686 // not correctly indicate which space is not properly mangled.
687 HeapWord* limit = (HeapWord*) virtual_space()->high();
688 eden_space()->check_mangled_unused_area(limit);
689 from_space()->check_mangled_unused_area(limit);
690 to_space()->check_mangled_unused_area(limit);
691 }
692 // When an existing space is being initialized, it is not
693 // mangled because the space has been previously mangled.
694 eden_space()->initialize(edenMR,
695 SpaceDecorator::Clear,
696 SpaceDecorator::DontMangle);
697 to_space()->initialize(toMR,
698 SpaceDecorator::Clear,
699 SpaceDecorator::DontMangle);
700 from_space()->initialize(fromMR,
701 SpaceDecorator::DontClear,
702 SpaceDecorator::DontMangle);
704 assert(from_space()->top() == old_from_top, "from top changed!");
706 if (PrintAdaptiveSizePolicy) {
707 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
708 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
710 gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
711 "collection: %d "
712 "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
713 "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
714 heap->total_collections(),
715 old_from, old_to,
716 from_space()->capacity_in_bytes(),
717 to_space()->capacity_in_bytes());
718 gclog_or_tty->cr();
719 }
720 }
722 void PSYoungGen::swap_spaces() {
723 MutableSpace* s = from_space();
724 _from_space = to_space();
725 _to_space = s;
727 // Now update the decorators.
728 PSMarkSweepDecorator* md = from_mark_sweep();
729 _from_mark_sweep = to_mark_sweep();
730 _to_mark_sweep = md;
732 assert(from_mark_sweep()->space() == from_space(), "Sanity");
733 assert(to_mark_sweep()->space() == to_space(), "Sanity");
734 }
736 size_t PSYoungGen::capacity_in_bytes() const {
737 return eden_space()->capacity_in_bytes()
738 + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
739 }
742 size_t PSYoungGen::used_in_bytes() const {
743 return eden_space()->used_in_bytes()
744 + from_space()->used_in_bytes(); // to_space() is only used during scavenge
745 }
748 size_t PSYoungGen::free_in_bytes() const {
749 return eden_space()->free_in_bytes()
750 + from_space()->free_in_bytes(); // to_space() is only used during scavenge
751 }
753 size_t PSYoungGen::capacity_in_words() const {
754 return eden_space()->capacity_in_words()
755 + from_space()->capacity_in_words(); // to_space() is only used during scavenge
756 }
759 size_t PSYoungGen::used_in_words() const {
760 return eden_space()->used_in_words()
761 + from_space()->used_in_words(); // to_space() is only used during scavenge
762 }
765 size_t PSYoungGen::free_in_words() const {
766 return eden_space()->free_in_words()
767 + from_space()->free_in_words(); // to_space() is only used during scavenge
768 }
770 void PSYoungGen::object_iterate(ObjectClosure* blk) {
771 eden_space()->object_iterate(blk);
772 from_space()->object_iterate(blk);
773 to_space()->object_iterate(blk);
774 }
776 void PSYoungGen::precompact() {
777 eden_mark_sweep()->precompact();
778 from_mark_sweep()->precompact();
779 to_mark_sweep()->precompact();
780 }
782 void PSYoungGen::adjust_pointers() {
783 eden_mark_sweep()->adjust_pointers();
784 from_mark_sweep()->adjust_pointers();
785 to_mark_sweep()->adjust_pointers();
786 }
788 void PSYoungGen::compact() {
789 eden_mark_sweep()->compact(ZapUnusedHeapArea);
790 from_mark_sweep()->compact(ZapUnusedHeapArea);
791 // Mark sweep stores preserved markOops in to space, don't disturb!
792 to_mark_sweep()->compact(false);
793 }
795 void PSYoungGen::print() const { print_on(tty); }
796 void PSYoungGen::print_on(outputStream* st) const {
797 st->print(" %-15s", "PSYoungGen");
798 if (PrintGCDetails && Verbose) {
799 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
800 capacity_in_bytes(), used_in_bytes());
801 } else {
802 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
803 capacity_in_bytes()/K, used_in_bytes()/K);
804 }
805 virtual_space()->print_space_boundaries_on(st);
806 st->print(" eden"); eden_space()->print_on(st);
807 st->print(" from"); from_space()->print_on(st);
808 st->print(" to "); to_space()->print_on(st);
809 }
811 // Note that a space is not printed before the [NAME:
812 void PSYoungGen::print_used_change(size_t prev_used) const {
813 gclog_or_tty->print("[%s:", name());
814 gclog_or_tty->print(" " SIZE_FORMAT "K"
815 "->" SIZE_FORMAT "K"
816 "(" SIZE_FORMAT "K)",
817 prev_used / K, used_in_bytes() / K,
818 capacity_in_bytes() / K);
819 gclog_or_tty->print("]");
820 }
822 size_t PSYoungGen::available_for_expansion() {
823 ShouldNotReachHere();
824 return 0;
825 }
827 size_t PSYoungGen::available_for_contraction() {
828 ShouldNotReachHere();
829 return 0;
830 }
832 size_t PSYoungGen::available_to_min_gen() {
833 assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
834 return virtual_space()->committed_size() - min_gen_size();
835 }
837 // This method assumes that from-space has live data and that
838 // any shrinkage of the young gen is limited by location of
839 // from-space.
840 size_t PSYoungGen::available_to_live() {
841 size_t delta_in_survivor = 0;
842 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
843 const size_t space_alignment = heap->intra_heap_alignment();
844 const size_t gen_alignment = heap->young_gen_alignment();
846 MutableSpace* space_shrinking = NULL;
847 if (from_space()->end() > to_space()->end()) {
848 space_shrinking = from_space();
849 } else {
850 space_shrinking = to_space();
851 }
853 // Include any space that is committed but not included in
854 // the survivor spaces.
855 assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
856 "Survivor space beyond high end");
857 size_t unused_committed = pointer_delta(virtual_space()->high(),
858 space_shrinking->end(), sizeof(char));
860 if (space_shrinking->is_empty()) {
861 // Don't let the space shrink to 0
862 assert(space_shrinking->capacity_in_bytes() >= space_alignment,
863 "Space is too small");
864 delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
865 } else {
866 delta_in_survivor = pointer_delta(space_shrinking->end(),
867 space_shrinking->top(),
868 sizeof(char));
869 }
871 size_t delta_in_bytes = unused_committed + delta_in_survivor;
872 delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
873 return delta_in_bytes;
874 }
876 // Return the number of bytes available for resizing down the young
877 // generation. This is the minimum of
878 // input "bytes"
879 // bytes to the minimum young gen size
880 // bytes to the size currently being used + some small extra
881 size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
882 // Allow shrinkage into the current eden but keep eden large enough
883 // to maintain the minimum young gen size
884 bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
885 return align_size_down(bytes, virtual_space()->alignment());
886 }
888 void PSYoungGen::reset_after_change() {
889 ShouldNotReachHere();
890 }
892 void PSYoungGen::reset_survivors_after_shrink() {
893 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
894 (HeapWord*)virtual_space()->high_boundary());
895 PSScavenge::reference_processor()->set_span(_reserved);
897 MutableSpace* space_shrinking = NULL;
898 if (from_space()->end() > to_space()->end()) {
899 space_shrinking = from_space();
900 } else {
901 space_shrinking = to_space();
902 }
904 HeapWord* new_end = (HeapWord*)virtual_space()->high();
905 assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
906 // Was there a shrink of the survivor space?
907 if (new_end < space_shrinking->end()) {
908 MemRegion mr(space_shrinking->bottom(), new_end);
909 space_shrinking->initialize(mr,
910 SpaceDecorator::DontClear,
911 SpaceDecorator::Mangle);
912 }
913 }
915 // This method currently does not expect to expand into eden (i.e.,
916 // the virtual space boundaries is expected to be consistent
917 // with the eden boundaries..
918 void PSYoungGen::post_resize() {
919 assert_locked_or_safepoint(Heap_lock);
920 assert((eden_space()->bottom() < to_space()->bottom()) &&
921 (eden_space()->bottom() < from_space()->bottom()),
922 "Eden is assumed to be below the survivor spaces");
924 MemRegion cmr((HeapWord*)virtual_space()->low(),
925 (HeapWord*)virtual_space()->high());
926 Universe::heap()->barrier_set()->resize_covered_region(cmr);
927 space_invariants();
928 }
932 void PSYoungGen::update_counters() {
933 if (UsePerfData) {
934 _eden_counters->update_all();
935 _from_counters->update_all();
936 _to_counters->update_all();
937 _gen_counters->update_all();
938 }
939 }
941 void PSYoungGen::verify() {
942 eden_space()->verify();
943 from_space()->verify();
944 to_space()->verify();
945 }
947 #ifndef PRODUCT
948 void PSYoungGen::record_spaces_top() {
949 assert(ZapUnusedHeapArea, "Not mangling unused space");
950 eden_space()->set_top_for_allocations();
951 from_space()->set_top_for_allocations();
952 to_space()->set_top_for_allocations();
953 }
954 #endif