void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) { assert(eden_size < virtual_space()->committed_size(), "just checking"); assert(eden_size > 0 && survivor_size > 0, "just checking"); // Initial layout is Eden, to, from. After swapping survivor spaces, // that leaves us with Eden, from, to, which is step one in our two // step resize-with-live-data procedure. char *eden_start = virtual_space()->low(); char *to_start = eden_start + eden_size; char *from_start = to_start + survivor_size; char *from_end = from_start + survivor_size; assert(from_end == virtual_space()->high(), "just checking"); assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); assert(is_object_aligned((intptr_t)to_start), "checking alignment"); assert(is_object_aligned((intptr_t)from_start), "checking alignment"); MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start); MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start); MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end); eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea); to_space()->initialize(to_mr , true, ZapUnusedHeapArea); from_space()->initialize(from_mr, true, ZapUnusedHeapArea); }
// This method assumes that from-space has live data and that // any shrinkage of the young gen is limited by location of // from-space. size_t PSYoungGen::available_to_live() { size_t delta_in_survivor = 0; ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t space_alignment = heap->intra_heap_alignment(); const size_t gen_alignment = heap->young_gen_alignment(); MutableSpace* space_shrinking = NULL; if (from_space()->end() > to_space()->end()) { space_shrinking = from_space(); } else { space_shrinking = to_space(); } // Include any space that is committed but not included in // the survivor spaces. assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(), "Survivor space beyond high end"); size_t unused_committed = pointer_delta(virtual_space()->high(), space_shrinking->end(), sizeof(char)); if (space_shrinking->is_empty()) { // Don't let the space shrink to 0 assert(space_shrinking->capacity_in_bytes() >= space_alignment, "Space is too small"); delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment; } else { delta_in_survivor = pointer_delta(space_shrinking->end(), space_shrinking->top(), sizeof(char)); } size_t delta_in_bytes = unused_committed + delta_in_survivor; delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment); return delta_in_bytes; }
size_t ASPSOldGen::available_for_expansion() { assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned"); assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size"); ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); size_t result = gen_size_limit() - virtual_space()->committed_size(); size_t result_aligned = align_size_down(result, heap->old_gen_alignment()); return result_aligned; }
// This method currently does not expect to expand into eden (i.e., // the virtual space boundaries is expected to be consistent // with the eden boundaries.. void PSYoungGen::post_resize() { assert_locked_or_safepoint(Heap_lock); assert((eden_space()->bottom() < to_space()->bottom()) && (eden_space()->bottom() < from_space()->bottom()), "Eden is assumed to be below the survivor spaces"); MemRegion cmr((HeapWord*)virtual_space()->low(), (HeapWord*)virtual_space()->high()); Universe::heap()->barrier_set()->resize_covered_region(cmr); space_invariants(); }
void PSYoungGen::space_invariants() { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t alignment = heap->intra_heap_alignment(); // Currently, our eden size cannot shrink to zero guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small"); guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small"); guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small"); // Relationship of spaces to each other char* eden_start = (char*)eden_space()->bottom(); char* eden_end = (char*)eden_space()->end(); char* from_start = (char*)from_space()->bottom(); char* from_end = (char*)from_space()->end(); char* to_start = (char*)to_space()->bottom(); char* to_end = (char*)to_space()->end(); guarantee(eden_start >= virtual_space()->low(), "eden bottom"); guarantee(eden_start < eden_end, "eden space consistency"); guarantee(from_start < from_end, "from space consistency"); guarantee(to_start < to_end, "to space consistency"); // Check whether from space is below to space if (from_start < to_start) { // Eden, from, to guarantee(eden_end <= from_start, "eden/from boundary"); guarantee(from_end <= to_start, "from/to boundary"); guarantee(to_end <= virtual_space()->high(), "to end"); } else { // Eden, to, from guarantee(eden_end <= to_start, "eden/to boundary"); guarantee(to_end <= from_start, "to/from boundary"); guarantee(from_end <= virtual_space()->high(), "from end"); } // More checks that the virtual space is consistent with the spaces assert(virtual_space()->committed_size() >= (eden_space()->capacity_in_bytes() + to_space()->capacity_in_bytes() + from_space()->capacity_in_bytes()), "Committed size is inconsistent"); assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), "Space invariant"); char* eden_top = (char*)eden_space()->top(); char* from_top = (char*)from_space()->top(); char* to_top = (char*)to_space()->top(); assert(eden_top <= virtual_space()->high(), "eden top"); assert(from_top <= virtual_space()->high(), "from top"); assert(to_top <= virtual_space()->high(), "to top"); virtual_space()->verify(); }
// This method assumes that from-space has live data and that // any shrinkage of the young gen is limited by location of // from-space. size_t ASParNewGeneration::available_to_live() const { #undef SHRINKS_AT_END_OF_EDEN #ifdef SHRINKS_AT_END_OF_EDEN size_t delta_in_survivor = 0; ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t space_alignment = heap->intra_heap_alignment(); const size_t gen_alignment = heap->object_heap_alignment(); MutableSpace* space_shrinking = NULL; if (from_space()->end() > to_space()->end()) { space_shrinking = from_space(); } else { space_shrinking = to_space(); } // Include any space that is committed but not included in // the survivor spaces. assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(), "Survivor space beyond high end"); size_t unused_committed = pointer_delta(virtual_space()->high(), space_shrinking->end(), sizeof(char)); if (space_shrinking->is_empty()) { // Don't let the space shrink to 0 assert(space_shrinking->capacity_in_bytes() >= space_alignment, "Space is too small"); delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment; } else { delta_in_survivor = pointer_delta(space_shrinking->end(), space_shrinking->top(), sizeof(char)); } size_t delta_in_bytes = unused_committed + delta_in_survivor; delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment); return delta_in_bytes; #else // The only space available for shrinking is in to-space if it // is above from-space. if (to()->bottom() > from()->bottom()) { const size_t alignment = os::vm_page_size(); if (to()->capacity() < alignment) { return 0; } else { return to()->capacity() - alignment; } } else { return 0; } #endif }
void PSYoungGen::compute_initial_space_boundaries() { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); // Compute sizes size_t alignment = heap->intra_heap_alignment(); size_t size = virtual_space()->committed_size(); size_t survivor_size = size / InitialSurvivorRatio; survivor_size = align_size_down(survivor_size, alignment); // ... but never less than an alignment survivor_size = MAX2(survivor_size, alignment); // Young generation is eden + 2 survivor spaces size_t eden_size = size - (2 * survivor_size); // Now go ahead and set 'em. set_space_boundaries(eden_size, survivor_size); space_invariants(); if (UsePerfData) { _eden_counters->update_capacity(); _from_counters->update_capacity(); _to_counters->update_capacity(); } }
void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) { assert(_init_gen_size != 0, "Should have a finite size"); _virtual_space = new PSVirtualSpace(rs, alignment); if (!virtual_space()->expand_by(_init_gen_size)) { vm_exit_during_initialization("Could not reserve enough space for " "object heap"); } }
size_t ASPSYoungGen::available_for_expansion() { size_t current_committed_size = virtual_space()->committed_size(); assert((gen_size_limit() >= current_committed_size), "generation size limit is wrong"); ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); size_t result = gen_size_limit() - current_committed_size; size_t result_aligned = align_size_down(result, heap->generation_alignment()); return result_aligned; }
// Changes from PSYoungGen version // value of "alignment" void ASParNewGeneration::space_invariants() { const size_t alignment = os::vm_page_size(); // Currently, our eden size cannot shrink to zero guarantee(eden()->capacity() >= alignment, "eden too small"); guarantee(from()->capacity() >= alignment, "from too small"); guarantee(to()->capacity() >= alignment, "to too small"); // Relationship of spaces to each other char* eden_start = (char*)eden()->bottom(); char* eden_end = (char*)eden()->end(); char* from_start = (char*)from()->bottom(); char* from_end = (char*)from()->end(); char* to_start = (char*)to()->bottom(); char* to_end = (char*)to()->end(); guarantee(eden_start >= virtual_space()->low(), "eden bottom"); guarantee(eden_start < eden_end, "eden space consistency"); guarantee(from_start < from_end, "from space consistency"); guarantee(to_start < to_end, "to space consistency"); // Check whether from space is below to space if (from_start < to_start) { // Eden, from, to guarantee(eden_end <= from_start, "eden/from boundary"); guarantee(from_end <= to_start, "from/to boundary"); guarantee(to_end <= virtual_space()->high(), "to end"); } else { // Eden, to, from guarantee(eden_end <= to_start, "eden/to boundary"); guarantee(to_end <= from_start, "to/from boundary"); guarantee(from_end <= virtual_space()->high(), "from end"); } // More checks that the virtual space is consistent with the spaces assert(virtual_space()->committed_size() >= (eden()->capacity() + to()->capacity() + from()->capacity()), "Committed size is inconsistent"); assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), "Space invariant"); char* eden_top = (char*)eden()->top(); char* from_top = (char*)from()->top(); char* to_top = (char*)to()->top(); assert(eden_top <= virtual_space()->high(), "eden top"); assert(from_top <= virtual_space()->high(), "from top"); assert(to_top <= virtual_space()->high(), "to top"); }
// Return the number of bytes the young gen is willing give up. // // Future implementations could check the survivors and if to_space is in the // right place (below from_space), take a chunk from to_space. size_t ASPSYoungGen::available_for_contraction() { size_t uncommitted_bytes = virtual_space()->uncommitted_size(); if (uncommitted_bytes != 0) { return uncommitted_bytes; } if (eden_space()->is_empty()) { // Respect the minimum size for eden and for the young gen as a whole. ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t eden_alignment = heap->intra_heap_alignment(); const size_t gen_alignment = heap->young_gen_alignment(); assert(eden_space()->capacity_in_bytes() >= eden_alignment, "Alignment is wrong"); size_t eden_avail = eden_space()->capacity_in_bytes() - eden_alignment; eden_avail = align_size_down(eden_avail, gen_alignment); assert(virtual_space()->committed_size() >= min_gen_size(), "minimum gen size is wrong"); size_t gen_avail = virtual_space()->committed_size() - min_gen_size(); assert(virtual_space()->is_aligned(gen_avail), "not aligned"); const size_t max_contraction = MIN2(eden_avail, gen_avail); // See comment for ASPSOldGen::available_for_contraction() // for reasons the "increment" fraction is used. PSAdaptiveSizePolicy* policy = heap->size_policy(); size_t result = policy->eden_increment_aligned_down(max_contraction); size_t result_aligned = align_size_down(result, gen_alignment); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("ASPSYoungGen::available_for_contraction: %d K", result_aligned/K); gclog_or_tty->print_cr(" max_contraction %d K", max_contraction/K); gclog_or_tty->print_cr(" eden_avail %d K", eden_avail/K); gclog_or_tty->print_cr(" gen_avail %d K", gen_avail/K); } return result_aligned; } return 0; }
size_t ASPSOldGen::available_for_contraction() { size_t uncommitted_bytes = virtual_space()->uncommitted_size(); if (uncommitted_bytes != 0) { return uncommitted_bytes; } ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t gen_alignment = heap->old_gen_alignment(); PSAdaptiveSizePolicy* policy = heap->size_policy(); const size_t working_size = used_in_bytes() + (size_t) policy->avg_promoted()->padded_average(); const size_t working_aligned = align_size_up(working_size, gen_alignment); const size_t working_or_min = MAX2(working_aligned, min_gen_size()); if (working_or_min > reserved().byte_size()) { // If the used or minimum gen size (aligned up) is greater // than the total reserved size, then the space available // for contraction should (after proper alignment) be 0 return 0; } const size_t max_contraction = reserved().byte_size() - working_or_min; // Use the "increment" fraction instead of the "decrement" fraction // to allow the other gen to expand more aggressively. The // "decrement" fraction is conservative because its intent is to // only reduce the footprint. size_t result = policy->promo_increment_aligned_down(max_contraction); // Also adjust for inter-generational alignment size_t result_aligned = align_size_down(result, gen_alignment); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("\nASPSOldGen::available_for_contraction:" " %d K / 0x%x", result_aligned/K, result_aligned); gclog_or_tty->print_cr(" reserved().byte_size() %d K / 0x%x ", reserved().byte_size()/K, reserved().byte_size()); size_t working_promoted = (size_t) policy->avg_promoted()->padded_average(); gclog_or_tty->print_cr(" padded promoted %d K / 0x%x", working_promoted/K, working_promoted); gclog_or_tty->print_cr(" used %d K / 0x%x", used_in_bytes()/K, used_in_bytes()); gclog_or_tty->print_cr(" min_gen_size() %d K / 0x%x", min_gen_size()/K, min_gen_size()); gclog_or_tty->print_cr(" max_contraction %d K / 0x%x", max_contraction/K, max_contraction); gclog_or_tty->print_cr(" without alignment %d K / 0x%x", policy->promo_increment(max_contraction)/K, policy->promo_increment(max_contraction)); gclog_or_tty->print_cr(" alignment 0x%x", gen_alignment); } assert(result_aligned <= max_contraction, "arithmetic is wrong"); return result_aligned; }
void PSYoungGen::reset_survivors_after_shrink() { _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), (HeapWord*)virtual_space()->high_boundary()); PSScavenge::reference_processor()->set_span(_reserved); MutableSpace* space_shrinking = NULL; if (from_space()->end() > to_space()->end()) { space_shrinking = from_space(); } else { space_shrinking = to_space(); } HeapWord* new_end = (HeapWord*)virtual_space()->high(); assert(new_end >= space_shrinking->bottom(), "Shrink was too large"); // Was there a shrink of the survivor space? if (new_end < space_shrinking->end()) { MemRegion mr(space_shrinking->bottom(), new_end); space_shrinking->initialize(mr, SpaceDecorator::DontClear, SpaceDecorator::Mangle); } }
void PSYoungGen::print_on(outputStream* st) const { st->print(" %-15s", "PSYoungGen"); if (PrintGCDetails && Verbose) { st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT, capacity_in_bytes(), used_in_bytes()); } else { st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", capacity_in_bytes()/K, used_in_bytes()/K); } virtual_space()->print_space_boundaries_on(st); st->print(" eden"); eden_space()->print_on(st); st->print(" from"); from_space()->print_on(st); st->print(" to "); to_space()->print_on(st); }
// The current implementation only considers to the end of eden. // If to_space is below from_space, to_space is not considered. // to_space can be. size_t ASPSYoungGen::available_to_live() { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t alignment = heap->intra_heap_alignment(); // Include any space that is committed but is not in eden. size_t available = pointer_delta(eden_space()->bottom(), virtual_space()->low(), sizeof(char)); const size_t eden_capacity = eden_space()->capacity_in_bytes(); if (eden_space()->is_empty() && eden_capacity > alignment) { available += eden_capacity - alignment; } return available; }
void ASParNewGeneration::reset_survivors_after_shrink() { GenCollectedHeap* gch = GenCollectedHeap::heap(); HeapWord* new_end = (HeapWord*)virtual_space()->high(); if (from()->end() > to()->end()) { assert(new_end >= from()->end(), "Shrinking past from-space"); } else { assert(new_end >= to()->bottom(), "Shrink was too large"); // Was there a shrink of the survivor space? if (new_end < to()->end()) { MemRegion mr(to()->bottom(), new_end); to()->initialize(mr, SpaceDecorator::DontClear, SpaceDecorator::DontMangle); } } }
bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { const size_t alignment = virtual_space()->alignment(); size_t orig_size = virtual_space()->committed_size(); bool size_changed = false; // There used to be this guarantee there. // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments"); // Code below forces this requirement. In addition the desired eden // size and disired survivor sizes are desired goals and may // exceed the total generation size. assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking"); // Adjust new generation size const size_t eden_plus_survivors = align_size_up(eden_size + 2 * survivor_size, alignment); size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()), min_gen_size()); assert(desired_size <= max_size(), "just checking"); if (desired_size > orig_size) { // Grow the generation size_t change = desired_size - orig_size; assert(change % alignment == 0, "just checking"); HeapWord* prev_high = (HeapWord*) virtual_space()->high(); if (!virtual_space()->expand_by(change)) { return false; // Error if we fail to resize! } if (ZapUnusedHeapArea) { // Mangle newly committed space immediately because it // can be done here more simply that after the new // spaces have been computed. HeapWord* new_high = (HeapWord*) virtual_space()->high(); MemRegion mangle_region(prev_high, new_high); SpaceMangler::mangle_region(mangle_region); } size_changed = true; } else if (desired_size < orig_size) { size_t desired_change = orig_size - desired_size; assert(desired_change % alignment == 0, "just checking"); desired_change = limit_gen_shrink(desired_change); if (desired_change > 0) { virtual_space()->shrink_by(desired_change); reset_survivors_after_shrink(); size_changed = true; } } else { if (Verbose && PrintGC) { if (orig_size == gen_size_limit()) { gclog_or_tty->print_cr("PSYoung generation size at maximum: " SIZE_FORMAT "K", orig_size/K); } else if (orig_size == min_gen_size()) { gclog_or_tty->print_cr("PSYoung generation size at minium: " SIZE_FORMAT "K", orig_size/K); } } } if (size_changed) { post_resize(); if (Verbose && PrintGC) { size_t current_size = virtual_space()->committed_size(); gclog_or_tty->print_cr("PSYoung generation size changed: " SIZE_FORMAT "K->" SIZE_FORMAT "K", orig_size/K, current_size/K); } } guarantee(eden_plus_survivors <= virtual_space()->committed_size() || virtual_space()->committed_size() == max_size(), "Sanity"); return true; }
void ASPSOldGen::reset_after_change() { _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), (HeapWord*)virtual_space()->high_boundary()); post_resize(); }
void PSPermGen::compute_new_size(size_t used_before_collection) { // Update our padded average of objects allocated in perm // gen between collections. assert(used_before_collection >= _last_used, "negative allocation amount since last GC?"); const size_t alloc_since_last_gc = used_before_collection - _last_used; _avg_size->sample(alloc_since_last_gc); const size_t current_live = used_in_bytes(); // Stash away the current amount live for the next call to this method. _last_used = current_live; // We have different alignment constraints than the rest of the heap. const size_t alignment = MAX2(MinPermHeapExpansion, virtual_space()->alignment()); // Compute the desired size: // The free space is the newly computed padded average, // so the desired size is what's live + the free space. size_t desired_size = current_live + (size_t)_avg_size->padded_average(); desired_size = align_size_up(desired_size, alignment); // ...and no larger or smaller than our max and min allowed. desired_size = MAX2(MIN2(desired_size, _max_gen_size), _min_gen_size); assert(desired_size <= _max_gen_size, "just checking"); const size_t size_before = _virtual_space->committed_size(); if (desired_size == size_before) { // no change, we're done return; } { // We'll be growing or shrinking the heap: in either case, // we need to hold a lock. MutexLocker x(ExpandHeap_lock); if (desired_size > size_before) { const size_t change_bytes = desired_size - size_before; const size_t aligned_change_bytes = align_size_up(change_bytes, alignment); expand_by(aligned_change_bytes); } else { // Shrinking const size_t change_bytes = size_before - desired_size; const size_t aligned_change_bytes = align_size_down(change_bytes, alignment); shrink(aligned_change_bytes); } } // While this code isn't controlled by AdaptiveSizePolicy, it's // convenient to see all resizing decsions under the same flag. if (PrintAdaptiveSizePolicy) { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); gclog_or_tty->print_cr("AdaptiveSizePolicy::perm generation size: " "collection: %d " "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ", heap->total_collections(), size_before, _virtual_space->committed_size()); } }
void ASParNewGeneration::resize_spaces(size_t requested_eden_size, size_t requested_survivor_size) { assert(UseAdaptiveSizePolicy, "sanity check"); assert(requested_eden_size > 0 && requested_survivor_size > 0, "just checking"); CollectedHeap* heap = Universe::heap(); assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Sanity"); // We require eden and to space to be empty if ((!eden()->is_empty()) || (!to()->is_empty())) { return; } size_t cur_eden_size = eden()->capacity(); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("ASParNew::resize_spaces(requested_eden_size: " SIZE_FORMAT ", requested_survivor_size: " SIZE_FORMAT ")", requested_eden_size, requested_survivor_size); gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, eden()->bottom(), eden()->end(), pointer_delta(eden()->end(), eden()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, from()->bottom(), from()->end(), pointer_delta(from()->end(), from()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, to()->bottom(), to()->end(), pointer_delta( to()->end(), to()->bottom(), sizeof(char))); } // There's nothing to do if the new sizes are the same as the current if (requested_survivor_size == to()->capacity() && requested_survivor_size == from()->capacity() && requested_eden_size == eden()->capacity()) { if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" capacities are the right sizes, returning"); } return; } char* eden_start = (char*)eden()->bottom(); char* eden_end = (char*)eden()->end(); char* from_start = (char*)from()->bottom(); char* from_end = (char*)from()->end(); char* to_start = (char*)to()->bottom(); char* to_end = (char*)to()->end(); const size_t alignment = os::vm_page_size(); const bool maintain_minimum = (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); // Check whether from space is below to space if (from_start < to_start) { // Eden, from, to if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, from, to:"); } // Set eden // "requested_eden_size" is a goal for the size of eden // and may not be attainable. "eden_size" below is // calculated based on the location of from-space and // the goal for the size of eden. from-space is // fixed in place because it contains live data. // The calculation is done this way to avoid 32bit // overflow (i.e., eden_start + requested_eden_size // may too large for representation in 32bits). size_t eden_size; if (maintain_minimum) { // Only make eden larger than the requested size if // the minimum size of the generation has to be maintained. // This could be done in general but policy at a higher // level is determining a requested size for eden and that // should be honored unless there is a fundamental reason. eden_size = pointer_delta(from_start, eden_start, sizeof(char)); } else { eden_size = MIN2(requested_eden_size, pointer_delta(from_start, eden_start, sizeof(char))); } eden_size = align_size_down(eden_size, alignment); eden_end = eden_start + eden_size; assert(eden_end >= eden_start, "addition overflowed") // To may resize into from space as long as it is clear of live data. // From space must remain page aligned, though, so we need to do some // extra calculations. // First calculate an optimal to-space to_end = (char*)virtual_space()->high(); to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, sizeof(char)); // Does the optimal to-space overlap from-space? if (to_start < (char*)from()->end()) { // Calculate the minimum offset possible for from_end size_t from_size = pointer_delta(from()->top(), from_start, sizeof(char)); // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! if (from_size == 0) { from_size = alignment; } else { from_size = align_size_up(from_size, alignment); } from_end = from_start + from_size; assert(from_end > from_start, "addition overflow or from_size problem"); guarantee(from_end <= (char*)from()->end(), "from_end moved to the right"); // Now update to_start with the new from_end to_start = MAX2(from_end, to_start); } else { // If shrinking, move to-space down to abut the end of from-space // so that shrinking will move to-space down. If not shrinking // to-space is moving up to allow for growth on the next expansion. if (requested_eden_size <= cur_eden_size) { to_start = from_end; if (to_start + requested_survivor_size > to_start) { to_end = to_start + requested_survivor_size; } } // else leave to_end pointing to the high end of the virtual space. } guarantee(to_start != to_end, "to space is zero sized"); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); } } else { // Eden, to, from if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, to, from:"); } // Calculate the to-space boundaries based on // the start of from-space. to_end = from_start; to_start = (char*)pointer_delta(from_start, (char*)requested_survivor_size, sizeof(char)); // Calculate the ideal eden boundaries. // eden_end is already at the bottom of the generation assert(eden_start == virtual_space()->low(), "Eden is not starting at the low end of the virtual space"); if (eden_start + requested_eden_size >= eden_start) { eden_end = eden_start + requested_eden_size; } else { eden_end = to_start; } // Does eden intrude into to-space? to-space // gets priority but eden is not allowed to shrink // to 0. if (eden_end > to_start) { eden_end = to_start; } // Don't let eden shrink down to 0 or less. eden_end = MAX2(eden_end, eden_start + alignment); assert(eden_start + alignment >= eden_start, "Overflow"); size_t eden_size; if (maintain_minimum) { // Use all the space available. eden_end = MAX2(eden_end, to_start); eden_size = pointer_delta(eden_end, eden_start, sizeof(char)); eden_size = MIN2(eden_size, cur_eden_size); } else { eden_size = pointer_delta(eden_end, eden_start, sizeof(char)); } eden_size = align_size_down(eden_size, alignment); assert(maintain_minimum || eden_size <= requested_eden_size, "Eden size is too large"); assert(eden_size >= alignment, "Eden size is too small"); eden_end = eden_start + eden_size; // Move to-space down to eden. if (requested_eden_size < cur_eden_size) { to_start = eden_end; if (to_start + requested_survivor_size > to_start) { to_end = MIN2(from_start, to_start + requested_survivor_size); } else { to_end = from_start; } } // eden_end may have moved so again make sure // the to-space and eden don't overlap. to_start = MAX2(eden_end, to_start); // from-space size_t from_used = from()->used(); if (requested_survivor_size > from_used) { if (from_start + requested_survivor_size >= from_start) { from_end = from_start + requested_survivor_size; } if (from_end > virtual_space()->high()) { from_end = virtual_space()->high(); } } assert(to_start >= eden_end, "to-space should be above eden"); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); } } guarantee((HeapWord*)from_start <= from()->bottom(), "from start moved to the right"); guarantee((HeapWord*)from_end >= from()->top(), "from end moved into live data"); assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); assert(is_object_aligned((intptr_t)from_start), "checking alignment"); assert(is_object_aligned((intptr_t)to_start), "checking alignment"); MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); // Let's make sure the call to initialize doesn't reset "top"! HeapWord* old_from_top = from()->top(); // For PrintAdaptiveSizePolicy block below size_t old_from = from()->capacity(); size_t old_to = to()->capacity(); // If not clearing the spaces, do some checking to verify that // the spaces are already mangled. // Must check mangling before the spaces are reshaped. Otherwise, // the bottom or end of one space may have moved into another // a failure of the check may not correctly indicate which space // is not properly mangled. if (ZapUnusedHeapArea) { HeapWord* limit = (HeapWord*) virtual_space()->high(); eden()->check_mangled_unused_area(limit); from()->check_mangled_unused_area(limit); to()->check_mangled_unused_area(limit); } // The call to initialize NULL's the next compaction space eden()->initialize(edenMR, SpaceDecorator::Clear, SpaceDecorator::DontMangle); eden()->set_next_compaction_space(from()); to()->initialize(toMR , SpaceDecorator::Clear, SpaceDecorator::DontMangle); from()->initialize(fromMR, SpaceDecorator::DontClear, SpaceDecorator::DontMangle); assert(from()->top() == old_from_top, "from top changed!"); if (PrintAdaptiveSizePolicy) { GenCollectedHeap* gch = GenCollectedHeap::heap(); assert(gch->kind() == CollectedHeap::GenCollectedHeap, "Sanity"); gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " "collection: %d " "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", gch->total_collections(), old_from, old_to, from()->capacity(), to()->capacity()); gclog_or_tty->cr(); } }
// Return the number of bytes available for resizing down the young // generation. This is the minimum of // input "bytes" // bytes to the minimum young gen size // bytes to the size currently being used + some small extra size_t PSYoungGen::limit_gen_shrink(size_t bytes) { // Allow shrinkage into the current eden but keep eden large enough // to maintain the minimum young gen size bytes = MIN3(bytes, available_to_min_gen(), available_to_live()); return align_size_down(bytes, virtual_space()->alignment()); }
size_t ASParNewGeneration::available_to_min_gen() { assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant"); return virtual_space()->committed_size() - min_gen_size(); }
size_t PSYoungGen::available_to_min_gen() { assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant"); return virtual_space()->committed_size() - min_gen_size(); }
void PSYoungGen::initialize_work() { _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), (HeapWord*)virtual_space()->high_boundary()); MemRegion cmr((HeapWord*)virtual_space()->low(), (HeapWord*)virtual_space()->high()); Universe::heap()->barrier_set()->resize_covered_region(cmr); if (ZapUnusedHeapArea) { // Mangle newly committed space immediately because it // can be done here more simply that after the new // spaces have been computed. SpaceMangler::mangle_region(cmr); } if (UseNUMA) { _eden_space = new MutableNUMASpace(virtual_space()->alignment()); } else { _eden_space = new MutableSpace(virtual_space()->alignment()); } _from_space = new MutableSpace(virtual_space()->alignment()); _to_space = new MutableSpace(virtual_space()->alignment()); if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) { vm_exit_during_initialization("Could not allocate a young gen space"); } // Allocate the mark sweep views of spaces _eden_mark_sweep = new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio); _from_mark_sweep = new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio); _to_mark_sweep = new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio); if (_eden_mark_sweep == NULL || _from_mark_sweep == NULL || _to_mark_sweep == NULL) { vm_exit_during_initialization("Could not complete allocation" " of the young generation"); } // Generation Counters - generation 0, 3 subspaces _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space); // Compute maximum space sizes for performance counters ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); size_t alignment = heap->intra_heap_alignment(); size_t size = virtual_space()->reserved_size(); size_t max_survivor_size; size_t max_eden_size; if (UseAdaptiveSizePolicy) { max_survivor_size = size / MinSurvivorRatio; // round the survivor space size down to the nearest alignment // and make sure its size is greater than 0. max_survivor_size = align_size_down(max_survivor_size, alignment); max_survivor_size = MAX2(max_survivor_size, alignment); // set the maximum size of eden to be the size of the young gen // less two times the minimum survivor size. The minimum survivor // size for UseAdaptiveSizePolicy is one alignment. max_eden_size = size - 2 * alignment; } else { max_survivor_size = size / InitialSurvivorRatio; // round the survivor space size down to the nearest alignment // and make sure its size is greater than 0. max_survivor_size = align_size_down(max_survivor_size, alignment); max_survivor_size = MAX2(max_survivor_size, alignment); // set the maximum size of eden to be the size of the young gen // less two times the survivor size when the generation is 100% // committed. The minimum survivor size for -UseAdaptiveSizePolicy // is dependent on the committed portion (current capacity) of the // generation - the less space committed, the smaller the survivor // space, possibly as small as an alignment. However, we are interested // in the case where the young generation is 100% committed, as this // is the point where eden reachs its maximum size. At this point, // the size of a survivor space is max_survivor_size. max_eden_size = size - 2 * max_survivor_size; } _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space, _gen_counters); _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space, _gen_counters); _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space, _gen_counters); compute_initial_space_boundaries(); }
void PSYoungGen::resize_spaces(size_t requested_eden_size, size_t requested_survivor_size) { assert(UseAdaptiveSizePolicy, "sanity check"); assert(requested_eden_size > 0 && requested_survivor_size > 0, "just checking"); // We require eden and to space to be empty if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { return; } if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " SIZE_FORMAT ", requested_survivor_size: " SIZE_FORMAT ")", requested_eden_size, requested_survivor_size); gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, eden_space()->bottom(), eden_space()->end(), pointer_delta(eden_space()->end(), eden_space()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, from_space()->bottom(), from_space()->end(), pointer_delta(from_space()->end(), from_space()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, to_space()->bottom(), to_space()->end(), pointer_delta( to_space()->end(), to_space()->bottom(), sizeof(char))); } // There's nothing to do if the new sizes are the same as the current if (requested_survivor_size == to_space()->capacity_in_bytes() && requested_survivor_size == from_space()->capacity_in_bytes() && requested_eden_size == eden_space()->capacity_in_bytes()) { if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" capacities are the right sizes, returning"); } return; } char* eden_start = (char*)eden_space()->bottom(); char* eden_end = (char*)eden_space()->end(); char* from_start = (char*)from_space()->bottom(); char* from_end = (char*)from_space()->end(); char* to_start = (char*)to_space()->bottom(); char* to_end = (char*)to_space()->end(); ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t alignment = heap->intra_heap_alignment(); const bool maintain_minimum = (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); bool eden_from_to_order = from_start < to_start; // Check whether from space is below to space if (eden_from_to_order) { // Eden, from, to eden_from_to_order = true; if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, from, to:"); } // Set eden // "requested_eden_size" is a goal for the size of eden // and may not be attainable. "eden_size" below is // calculated based on the location of from-space and // the goal for the size of eden. from-space is // fixed in place because it contains live data. // The calculation is done this way to avoid 32bit // overflow (i.e., eden_start + requested_eden_size // may too large for representation in 32bits). size_t eden_size; if (maintain_minimum) { // Only make eden larger than the requested size if // the minimum size of the generation has to be maintained. // This could be done in general but policy at a higher // level is determining a requested size for eden and that // should be honored unless there is a fundamental reason. eden_size = pointer_delta(from_start, eden_start, sizeof(char)); } else { eden_size = MIN2(requested_eden_size, pointer_delta(from_start, eden_start, sizeof(char))); } eden_end = eden_start + eden_size; assert(eden_end >= eden_start, "addition overflowed"); // To may resize into from space as long as it is clear of live data. // From space must remain page aligned, though, so we need to do some // extra calculations. // First calculate an optimal to-space to_end = (char*)virtual_space()->high(); to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, sizeof(char)); // Does the optimal to-space overlap from-space? if (to_start < (char*)from_space()->end()) { assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); // Calculate the minimum offset possible for from_end size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char)); // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! if (from_size == 0) { from_size = alignment; } else { from_size = align_size_up(from_size, alignment); } from_end = from_start + from_size; assert(from_end > from_start, "addition overflow or from_size problem"); guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right"); // Now update to_start with the new from_end to_start = MAX2(from_end, to_start); } guarantee(to_start != to_end, "to space is zero sized"); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); } } else { // Eden, to, from if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, to, from:"); } // To space gets priority over eden resizing. Note that we position // to space as if we were able to resize from space, even though from // space is not modified. // Giving eden priority was tried and gave poorer performance. to_end = (char*)pointer_delta(virtual_space()->high(), (char*)requested_survivor_size, sizeof(char)); to_end = MIN2(to_end, from_start); to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, sizeof(char)); // if the space sizes are to be increased by several times then // 'to_start' will point beyond the young generation. In this case // 'to_start' should be adjusted. to_start = MAX2(to_start, eden_start + alignment); // Compute how big eden can be, then adjust end. // See comments above on calculating eden_end. size_t eden_size; if (maintain_minimum) { eden_size = pointer_delta(to_start, eden_start, sizeof(char)); } else { eden_size = MIN2(requested_eden_size, pointer_delta(to_start, eden_start, sizeof(char))); } eden_end = eden_start + eden_size; assert(eden_end >= eden_start, "addition overflowed"); // Could choose to not let eden shrink // to_start = MAX2(to_start, eden_end); // Don't let eden shrink down to 0 or less. eden_end = MAX2(eden_end, eden_start + alignment); to_start = MAX2(to_start, eden_end); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); } } guarantee((HeapWord*)from_start <= from_space()->bottom(), "from start moved to the right"); guarantee((HeapWord*)from_end >= from_space()->top(), "from end moved into live data"); assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); assert(is_object_aligned((intptr_t)from_start), "checking alignment"); assert(is_object_aligned((intptr_t)to_start), "checking alignment"); MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); // Let's make sure the call to initialize doesn't reset "top"! HeapWord* old_from_top = from_space()->top(); // For PrintAdaptiveSizePolicy block below size_t old_from = from_space()->capacity_in_bytes(); size_t old_to = to_space()->capacity_in_bytes(); if (ZapUnusedHeapArea) { // NUMA is a special case because a numa space is not mangled // in order to not prematurely bind its address to memory to // the wrong memory (i.e., don't want the GC thread to first // touch the memory). The survivor spaces are not numa // spaces and are mangled. if (UseNUMA) { if (eden_from_to_order) { mangle_survivors(from_space(), fromMR, to_space(), toMR); } else { mangle_survivors(to_space(), toMR, from_space(), fromMR); } } // If not mangling the spaces, do some checking to verify that // the spaces are already mangled. // The spaces should be correctly mangled at this point so // do some checking here. Note that they are not being mangled // in the calls to initialize(). // Must check mangling before the spaces are reshaped. Otherwise, // the bottom or end of one space may have moved into an area // covered by another space and a failure of the check may // not correctly indicate which space is not properly mangled. HeapWord* limit = (HeapWord*) virtual_space()->high(); eden_space()->check_mangled_unused_area(limit); from_space()->check_mangled_unused_area(limit); to_space()->check_mangled_unused_area(limit); } // When an existing space is being initialized, it is not // mangled because the space has been previously mangled. eden_space()->initialize(edenMR, SpaceDecorator::Clear, SpaceDecorator::DontMangle); to_space()->initialize(toMR, SpaceDecorator::Clear, SpaceDecorator::DontMangle); from_space()->initialize(fromMR, SpaceDecorator::DontClear, SpaceDecorator::DontMangle); assert(from_space()->top() == old_from_top, "from top changed!"); if (PrintAdaptiveSizePolicy) { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " "collection: %d " "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", heap->total_collections(), old_from, old_to, from_space()->capacity_in_bytes(), to_space()->capacity_in_bytes()); gclog_or_tty->cr(); } }
// Note that the the alignment used is the OS page size as // opposed to an alignment associated with the virtual space // (as is done in the ASPSYoungGen/ASPSOldGen) bool ASParNewGeneration::resize_generation(size_t eden_size, size_t survivor_size) { const size_t alignment = os::vm_page_size(); size_t orig_size = virtual_space()->committed_size(); bool size_changed = false; // There used to be this guarantee there. // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments"); // Code below forces this requirement. In addition the desired eden // size and disired survivor sizes are desired goals and may // exceed the total generation size. assert(min_gen_size() <= orig_size && orig_size <= max_gen_size(), "just checking"); // Adjust new generation size const size_t eden_plus_survivors = align_size_up(eden_size + 2 * survivor_size, alignment); size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_gen_size()), min_gen_size()); assert(desired_size <= max_gen_size(), "just checking"); if (desired_size > orig_size) { // Grow the generation size_t change = desired_size - orig_size; assert(change % alignment == 0, "just checking"); if (expand(change)) { return false; // Error if we fail to resize! } size_changed = true; } else if (desired_size < orig_size) { size_t desired_change = orig_size - desired_size; assert(desired_change % alignment == 0, "just checking"); desired_change = limit_gen_shrink(desired_change); if (desired_change > 0) { virtual_space()->shrink_by(desired_change); reset_survivors_after_shrink(); size_changed = true; } } else { if (Verbose && PrintGC) { if (orig_size == max_gen_size()) { gclog_or_tty->print_cr("ASParNew generation size at maximum: " SIZE_FORMAT "K", orig_size/K); } else if (orig_size == min_gen_size()) { gclog_or_tty->print_cr("ASParNew generation size at minium: " SIZE_FORMAT "K", orig_size/K); } } } if (size_changed) { MemRegion cmr((HeapWord*)virtual_space()->low(), (HeapWord*)virtual_space()->high()); GenCollectedHeap::heap()->barrier_set()->resize_covered_region(cmr); if (Verbose && PrintGC) { size_t current_size = virtual_space()->committed_size(); gclog_or_tty->print_cr("ASParNew generation size changed: " SIZE_FORMAT "K->" SIZE_FORMAT "K", orig_size/K, current_size/K); } } guarantee(eden_plus_survivors <= virtual_space()->committed_size() || virtual_space()->committed_size() == max_gen_size(), "Sanity"); return true; }
// Similar to PSYoungGen::resize_generation() but // allows sum of eden_size and 2 * survivor_size to exceed _max_gen_size // expands at the low end of the virtual space // moves the boundary between the generations in order to expand // some additional diagnostics // If no additional changes are required, this can be deleted // and the changes factored back into PSYoungGen::resize_generation(). bool ASPSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { const size_t alignment = virtual_space()->alignment(); size_t orig_size = virtual_space()->committed_size(); bool size_changed = false; // There used to be a guarantee here that // (eden_size + 2*survivor_size) <= _max_gen_size // This requirement is enforced by the calculation of desired_size // below. It may not be true on entry since the size of the // eden_size is no bounded by the generation size. assert(max_size() == reserved().byte_size(), "max gen size problem?"); assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking"); // Adjust new generation size const size_t eden_plus_survivors = align_size_up(eden_size + 2 * survivor_size, alignment); size_t desired_size = MAX2(MIN2(eden_plus_survivors, gen_size_limit()), min_gen_size()); assert(desired_size <= gen_size_limit(), "just checking"); if (desired_size > orig_size) { // Grow the generation size_t change = desired_size - orig_size; HeapWord* prev_low = (HeapWord*) virtual_space()->low(); if (!virtual_space()->expand_by(change)) { return false; } if (ZapUnusedHeapArea) { // Mangle newly committed space immediately because it // can be done here more simply that after the new // spaces have been computed. HeapWord* new_low = (HeapWord*) virtual_space()->low(); assert(new_low < prev_low, "Did not grow"); MemRegion mangle_region(new_low, prev_low); SpaceMangler::mangle_region(mangle_region); } size_changed = true; } else if (desired_size < orig_size) { size_t desired_change = orig_size - desired_size; // How much is available for shrinking. size_t available_bytes = limit_gen_shrink(desired_change); size_t change = MIN2(desired_change, available_bytes); virtual_space()->shrink_by(change); size_changed = true; } else { if (Verbose && PrintGC) { if (orig_size == gen_size_limit()) { gclog_or_tty->print_cr("ASPSYoung generation size at maximum: " SIZE_FORMAT "K", orig_size/K); } else if (orig_size == min_gen_size()) { gclog_or_tty->print_cr("ASPSYoung generation size at minium: " SIZE_FORMAT "K", orig_size/K); } } } if (size_changed) { reset_after_change(); if (Verbose && PrintGC) { size_t current_size = virtual_space()->committed_size(); gclog_or_tty->print_cr("ASPSYoung generation size changed: " SIZE_FORMAT "K->" SIZE_FORMAT "K", orig_size/K, current_size/K); } } guarantee(eden_plus_survivors <= virtual_space()->committed_size() || virtual_space()->committed_size() == max_size(), "Sanity"); return true; }
void ASPSYoungGen::resize_spaces(size_t requested_eden_size, size_t requested_survivor_size) { assert(UseAdaptiveSizePolicy, "sanity check"); assert(requested_eden_size > 0 && requested_survivor_size > 0, "just checking"); space_invariants(); // We require eden and to space to be empty if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { return; } if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " SIZE_FORMAT ", requested_survivor_size: " SIZE_FORMAT ")", requested_eden_size, requested_survivor_size); gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, eden_space()->bottom(), eden_space()->end(), pointer_delta(eden_space()->end(), eden_space()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, from_space()->bottom(), from_space()->end(), pointer_delta(from_space()->end(), from_space()->bottom(), sizeof(char))); gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT, to_space()->bottom(), to_space()->end(), pointer_delta( to_space()->end(), to_space()->bottom(), sizeof(char))); } // There's nothing to do if the new sizes are the same as the current if (requested_survivor_size == to_space()->capacity_in_bytes() && requested_survivor_size == from_space()->capacity_in_bytes() && requested_eden_size == eden_space()->capacity_in_bytes()) { if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" capacities are the right sizes, returning"); } return; } char* eden_start = (char*)virtual_space()->low(); char* eden_end = (char*)eden_space()->end(); char* from_start = (char*)from_space()->bottom(); char* from_end = (char*)from_space()->end(); char* to_start = (char*)to_space()->bottom(); char* to_end = (char*)to_space()->end(); assert(eden_start < from_start, "Cannot push into from_space"); ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); const size_t alignment = heap->intra_heap_alignment(); const bool maintain_minimum = (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size(); bool eden_from_to_order = from_start < to_start; // Check whether from space is below to space if (eden_from_to_order) { // Eden, from, to if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, from, to:"); } // Set eden // "requested_eden_size" is a goal for the size of eden // and may not be attainable. "eden_size" below is // calculated based on the location of from-space and // the goal for the size of eden. from-space is // fixed in place because it contains live data. // The calculation is done this way to avoid 32bit // overflow (i.e., eden_start + requested_eden_size // may too large for representation in 32bits). size_t eden_size; if (maintain_minimum) { // Only make eden larger than the requested size if // the minimum size of the generation has to be maintained. // This could be done in general but policy at a higher // level is determining a requested size for eden and that // should be honored unless there is a fundamental reason. eden_size = pointer_delta(from_start, eden_start, sizeof(char)); } else { eden_size = MIN2(requested_eden_size, pointer_delta(from_start, eden_start, sizeof(char))); } eden_end = eden_start + eden_size; assert(eden_end >= eden_start, "addition overflowed") // To may resize into from space as long as it is clear of live data. // From space must remain page aligned, though, so we need to do some // extra calculations. // First calculate an optimal to-space to_end = (char*)virtual_space()->high(); to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, sizeof(char)); // Does the optimal to-space overlap from-space? if (to_start < (char*)from_space()->end()) { assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); // Calculate the minimum offset possible for from_end size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char)); // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! if (from_size == 0) { from_size = alignment; } else { from_size = align_size_up(from_size, alignment); } from_end = from_start + from_size; assert(from_end > from_start, "addition overflow or from_size problem"); guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right"); // Now update to_start with the new from_end to_start = MAX2(from_end, to_start); } guarantee(to_start != to_end, "to space is zero sized"); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); } } else { // Eden, to, from if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" Eden, to, from:"); } // To space gets priority over eden resizing. Note that we position // to space as if we were able to resize from space, even though from // space is not modified. // Giving eden priority was tried and gave poorer performance. to_end = (char*)pointer_delta(virtual_space()->high(), (char*)requested_survivor_size, sizeof(char)); to_end = MIN2(to_end, from_start); to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size, sizeof(char)); // if the space sizes are to be increased by several times then // 'to_start' will point beyond the young generation. In this case // 'to_start' should be adjusted. to_start = MAX2(to_start, eden_start + alignment); // Compute how big eden can be, then adjust end. // See comments above on calculating eden_end. size_t eden_size; if (maintain_minimum) { eden_size = pointer_delta(to_start, eden_start, sizeof(char)); } else { eden_size = MIN2(requested_eden_size, pointer_delta(to_start, eden_start, sizeof(char))); } eden_end = eden_start + eden_size; assert(eden_end >= eden_start, "addition overflowed") // Don't let eden shrink down to 0 or less. eden_end = MAX2(eden_end, eden_start + alignment); to_start = MAX2(to_start, eden_end); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr(" [eden_start .. eden_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, eden_start, eden_end, pointer_delta(eden_end, eden_start, sizeof(char))); gclog_or_tty->print_cr(" [ to_start .. to_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, to_start, to_end, pointer_delta( to_end, to_start, sizeof(char))); gclog_or_tty->print_cr(" [from_start .. from_end): " "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, from_start, from_end, pointer_delta(from_end, from_start, sizeof(char))); } } guarantee((HeapWord*)from_start <= from_space()->bottom(), "from start moved to the right"); guarantee((HeapWord*)from_end >= from_space()->top(), "from end moved into live data"); assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); assert(is_object_aligned((intptr_t)from_start), "checking alignment"); assert(is_object_aligned((intptr_t)to_start), "checking alignment"); MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); // Let's make sure the call to initialize doesn't reset "top"! DEBUG_ONLY(HeapWord* old_from_top = from_space()->top();)