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;
}
// 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;
}