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;
}
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;
}