// 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(); }
// 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 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); }
// 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; }
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); }
PSHeapSummary ParallelScavengeHeap::create_ps_heap_summary() { PSOldGen* old = old_gen(); HeapWord* old_committed_end = (HeapWord*)old->virtual_space()->committed_high_addr(); VirtualSpaceSummary old_summary(old->reserved().start(), old_committed_end, old->reserved().end()); SpaceSummary old_space(old->reserved().start(), old_committed_end, old->used_in_bytes()); PSYoungGen* young = young_gen(); VirtualSpaceSummary young_summary(young->reserved().start(), (HeapWord*)young->virtual_space()->committed_high_addr(), young->reserved().end()); MutableSpace* eden = young_gen()->eden_space(); SpaceSummary eden_space(eden->bottom(), eden->end(), eden->used_in_bytes()); MutableSpace* from = young_gen()->from_space(); SpaceSummary from_space(from->bottom(), from->end(), from->used_in_bytes()); MutableSpace* to = young_gen()->to_space(); SpaceSummary to_space(to->bottom(), to->end(), to->used_in_bytes()); VirtualSpaceSummary heap_summary = create_heap_space_summary(); return PSHeapSummary(heap_summary, used(), old_summary, old_space, young_summary, eden_space, from_space, to_space); }
// Allocation HeapWord* allocate(size_t word_size) { HeapWord* result = eden_space()->cas_allocate(word_size); return result; }
void PSYoungGen::record_spaces_top() { assert(ZapUnusedHeapArea, "Not mangling unused space"); eden_space()->set_top_for_allocations(); from_space()->set_top_for_allocations(); to_space()->set_top_for_allocations(); }
void PSYoungGen::verify() { eden_space()->verify(); from_space()->verify(); to_space()->verify(); }
void PSYoungGen::object_iterate(ObjectClosure* blk) { eden_space()->object_iterate(blk); from_space()->object_iterate(blk); to_space()->object_iterate(blk); }
size_t PSYoungGen::free_in_words() const { return eden_space()->free_in_words() + from_space()->free_in_words(); // to_space() is only used during scavenge }
size_t PSYoungGen::used_in_bytes() const { return eden_space()->used_in_bytes() + from_space()->used_in_bytes(); // to_space() is only used during scavenge }
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(); } }
void PSYoungGen::verify(bool allow_dirty) { eden_space()->verify(allow_dirty); from_space()->verify(allow_dirty); to_space()->verify(allow_dirty); }
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();)