void PSOldGen::shrink(size_t bytes) {
assert_lock_strong(ExpandHeap_lock);
assert_locked_or_safepoint(Heap_lock);
size_t size = ReservedSpace::page_align_size_down(bytes);
if (size > 0) {
assert_lock_strong(ExpandHeap_lock);
_virtual_space.shrink_by(bytes);
post_resize();
if (Verbose && PrintGC) {
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size - bytes;
gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
SIZE_FORMAT "K to "
SIZE_FORMAT "K",
name(), old_mem_size/K, bytes/K, new_mem_size/K);
}
}
}
bool PSOldGen::expand_by(size_t bytes) {
assert_lock_strong(ExpandHeap_lock);
assert_locked_or_safepoint(Heap_lock);
bool result = _virtual_space.expand_by(bytes);
if (result) {
post_resize();
if (UsePerfData) {
_space_counters->update_capacity();
_gen_counters->update_all();
}
}
if (result && Verbose && PrintGC) {
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size - bytes;
gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
SIZE_FORMAT "K to "
SIZE_FORMAT "K",
name(), old_mem_size/K, bytes/K, new_mem_size/K);
}
return result;
}
void ASPSOldGen::reset_after_change() {
_reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
(HeapWord*)virtual_space()->high_boundary());
post_resize();
}
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;
}
