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; }
// 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::resize(size_t eden_size, size_t survivor_size) { // Resize the generation if needed. If the generation resize // reports false, do not attempt to resize the spaces. if (resize_generation(eden_size, survivor_size)) { // Then we lay out the spaces inside the generation resize_spaces(eden_size, survivor_size); space_invariants(); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print_cr("Young generation size: " "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(), _max_gen_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::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(); } }
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 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();)
// 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; }
size_t ASParNewGeneration::available_to_min_gen() { assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant"); return virtual_space()->committed_size() - min_gen_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(); } }
// 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; }