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(); } }
// 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::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()); } } }
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();)