void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
assert(eden_size < virtual_space()->committed_size(), "just checking");
assert(eden_size > 0 && survivor_size > 0, "just checking");
// Initial layout is Eden, to, from. After swapping survivor spaces,
// that leaves us with Eden, from, to, which is step one in our two
// step resize-with-live-data procedure.
char *eden_start = virtual_space()->low();
char *to_start = eden_start + eden_size;
char *from_start = to_start + survivor_size;
char *from_end = from_start + survivor_size;
assert(from_end == virtual_space()->high(), "just checking");
assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
assert(is_object_aligned((intptr_t)to_start), "checking alignment");
assert(is_object_aligned((intptr_t)from_start), "checking alignment");
MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
}
// This method assumes that from-space has live data and that
// any shrinkage of the young gen is limited by location of
// from-space.
size_t PSYoungGen::available_to_live() {
size_t delta_in_survivor = 0;
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
const size_t space_alignment = heap->intra_heap_alignment();
const size_t gen_alignment = heap->young_gen_alignment();
MutableSpace* space_shrinking = NULL;
if (from_space()->end() > to_space()->end()) {
space_shrinking = from_space();
} else {
space_shrinking = to_space();
}
// Include any space that is committed but not included in
// the survivor spaces.
assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
"Survivor space beyond high end");
size_t unused_committed = pointer_delta(virtual_space()->high(),
space_shrinking->end(), sizeof(char));
if (space_shrinking->is_empty()) {
// Don't let the space shrink to 0
assert(space_shrinking->capacity_in_bytes() >= space_alignment,
"Space is too small");
delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
} else {
delta_in_survivor = pointer_delta(space_shrinking->end(),
space_shrinking->top(),
sizeof(char));
}
size_t delta_in_bytes = unused_committed + delta_in_survivor;
delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
return delta_in_bytes;
}
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;
}
// 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::space_invariants() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
const size_t alignment = heap->intra_heap_alignment();
// Currently, our eden size cannot shrink to zero
guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
// Relationship of spaces to each other
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();
guarantee(eden_start >= virtual_space()->low(), "eden bottom");
guarantee(eden_start < eden_end, "eden space consistency");
guarantee(from_start < from_end, "from space consistency");
guarantee(to_start < to_end, "to space consistency");
// Check whether from space is below to space
if (from_start < to_start) {
// Eden, from, to
guarantee(eden_end <= from_start, "eden/from boundary");
guarantee(from_end <= to_start, "from/to boundary");
guarantee(to_end <= virtual_space()->high(), "to end");
} else {
// Eden, to, from
guarantee(eden_end <= to_start, "eden/to boundary");
guarantee(to_end <= from_start, "to/from boundary");
guarantee(from_end <= virtual_space()->high(), "from end");
}
// More checks that the virtual space is consistent with the spaces
assert(virtual_space()->committed_size() >=
(eden_space()->capacity_in_bytes() +
to_space()->capacity_in_bytes() +
from_space()->capacity_in_bytes()), "Committed size is inconsistent");
assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
"Space invariant");
char* eden_top = (char*)eden_space()->top();
char* from_top = (char*)from_space()->top();
char* to_top = (char*)to_space()->top();
assert(eden_top <= virtual_space()->high(), "eden top");
assert(from_top <= virtual_space()->high(), "from top");
assert(to_top <= virtual_space()->high(), "to top");
virtual_space()->verify();
}
// This method assumes that from-space has live data and that
// any shrinkage of the young gen is limited by location of
// from-space.
size_t ASParNewGeneration::available_to_live() const {
#undef SHRINKS_AT_END_OF_EDEN
#ifdef SHRINKS_AT_END_OF_EDEN
size_t delta_in_survivor = 0;
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
const size_t space_alignment = heap->intra_heap_alignment();
const size_t gen_alignment = heap->object_heap_alignment();
MutableSpace* space_shrinking = NULL;
if (from_space()->end() > to_space()->end()) {
space_shrinking = from_space();
} else {
space_shrinking = to_space();
}
// Include any space that is committed but not included in
// the survivor spaces.
assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
"Survivor space beyond high end");
size_t unused_committed = pointer_delta(virtual_space()->high(),
space_shrinking->end(), sizeof(char));
if (space_shrinking->is_empty()) {
// Don't let the space shrink to 0
assert(space_shrinking->capacity_in_bytes() >= space_alignment,
"Space is too small");
delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
} else {
delta_in_survivor = pointer_delta(space_shrinking->end(),
space_shrinking->top(),
sizeof(char));
}
size_t delta_in_bytes = unused_committed + delta_in_survivor;
delta_in_bytes = align_size_down(delta_in_bytes, gen_alignment);
return delta_in_bytes;
#else
// The only space available for shrinking is in to-space if it
// is above from-space.
if (to()->bottom() > from()->bottom()) {
const size_t alignment = os::vm_page_size();
if (to()->capacity() < alignment) {
return 0;
} else {
return to()->capacity() - alignment;
}
} else {
return 0;
}
#endif
}
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();
}
}
void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
assert(_init_gen_size != 0, "Should have a finite size");
_virtual_space = new PSVirtualSpace(rs, alignment);
if (!virtual_space()->expand_by(_init_gen_size)) {
vm_exit_during_initialization("Could not reserve enough space for "
"object heap");
}
}
size_t ASPSYoungGen::available_for_expansion() {
size_t current_committed_size = virtual_space()->committed_size();
assert((gen_size_limit() >= current_committed_size),
"generation size limit is wrong");
ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
size_t result = gen_size_limit() - current_committed_size;
size_t result_aligned = align_size_down(result, heap->generation_alignment());
return result_aligned;
}
// Changes from PSYoungGen version
// value of "alignment"
void ASParNewGeneration::space_invariants() {
const size_t alignment = os::vm_page_size();
// Currently, our eden size cannot shrink to zero
guarantee(eden()->capacity() >= alignment, "eden too small");
guarantee(from()->capacity() >= alignment, "from too small");
guarantee(to()->capacity() >= alignment, "to too small");
// Relationship of spaces to each other
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();
guarantee(eden_start >= virtual_space()->low(), "eden bottom");
guarantee(eden_start < eden_end, "eden space consistency");
guarantee(from_start < from_end, "from space consistency");
guarantee(to_start < to_end, "to space consistency");
// Check whether from space is below to space
if (from_start < to_start) {
// Eden, from, to
guarantee(eden_end <= from_start, "eden/from boundary");
guarantee(from_end <= to_start, "from/to boundary");
guarantee(to_end <= virtual_space()->high(), "to end");
} else {
// Eden, to, from
guarantee(eden_end <= to_start, "eden/to boundary");
guarantee(to_end <= from_start, "to/from boundary");
guarantee(from_end <= virtual_space()->high(), "from end");
}
// More checks that the virtual space is consistent with the spaces
assert(virtual_space()->committed_size() >=
(eden()->capacity() +
to()->capacity() +
from()->capacity()), "Committed size is inconsistent");
assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
"Space invariant");
char* eden_top = (char*)eden()->top();
char* from_top = (char*)from()->top();
char* to_top = (char*)to()->top();
assert(eden_top <= virtual_space()->high(), "eden top");
assert(from_top <= virtual_space()->high(), "from top");
assert(to_top <= virtual_space()->high(), "to top");
}
// 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;
}
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;
}
void PSYoungGen::reset_survivors_after_shrink() {
_reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
(HeapWord*)virtual_space()->high_boundary());
PSScavenge::reference_processor()->set_span(_reserved);
MutableSpace* space_shrinking = NULL;
if (from_space()->end() > to_space()->end()) {
space_shrinking = from_space();
} else {
space_shrinking = to_space();
}
HeapWord* new_end = (HeapWord*)virtual_space()->high();
assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
// Was there a shrink of the survivor space?
if (new_end < space_shrinking->end()) {
MemRegion mr(space_shrinking->bottom(), new_end);
space_shrinking->initialize(mr,
SpaceDecorator::DontClear,
SpaceDecorator::Mangle);
}
}
void PSYoungGen::print_on(outputStream* st) const {
st->print(" %-15s", "PSYoungGen");
if (PrintGCDetails && Verbose) {
st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
capacity_in_bytes(), used_in_bytes());
} else {
st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
capacity_in_bytes()/K, used_in_bytes()/K);
}
virtual_space()->print_space_boundaries_on(st);
st->print(" eden"); eden_space()->print_on(st);
st->print(" from"); from_space()->print_on(st);
st->print(" to "); to_space()->print_on(st);
}
// The current implementation only considers to the end of eden.
// If to_space is below from_space, to_space is not considered.
// to_space can be.
size_t ASPSYoungGen::available_to_live() {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
const size_t alignment = heap->intra_heap_alignment();
// Include any space that is committed but is not in eden.
size_t available = pointer_delta(eden_space()->bottom(),
virtual_space()->low(),
sizeof(char));
const size_t eden_capacity = eden_space()->capacity_in_bytes();
if (eden_space()->is_empty() && eden_capacity > alignment) {
available += eden_capacity - alignment;
}
return available;
}
void ASParNewGeneration::reset_survivors_after_shrink() {
GenCollectedHeap* gch = GenCollectedHeap::heap();
HeapWord* new_end = (HeapWord*)virtual_space()->high();
if (from()->end() > to()->end()) {
assert(new_end >= from()->end(), "Shrinking past from-space");
} else {
assert(new_end >= to()->bottom(), "Shrink was too large");
// Was there a shrink of the survivor space?
if (new_end < to()->end()) {
MemRegion mr(to()->bottom(), new_end);
to()->initialize(mr,
SpaceDecorator::DontClear,
SpaceDecorator::DontMangle);
}
}
}
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 ASPSOldGen::reset_after_change() {
_reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
(HeapWord*)virtual_space()->high_boundary());
post_resize();
}
void PSPermGen::compute_new_size(size_t used_before_collection) {
// Update our padded average of objects allocated in perm
// gen between collections.
assert(used_before_collection >= _last_used,
"negative allocation amount since last GC?");
const size_t alloc_since_last_gc = used_before_collection - _last_used;
_avg_size->sample(alloc_since_last_gc);
const size_t current_live = used_in_bytes();
// Stash away the current amount live for the next call to this method.
_last_used = current_live;
// We have different alignment constraints than the rest of the heap.
const size_t alignment = MAX2(MinPermHeapExpansion,
virtual_space()->alignment());
// Compute the desired size:
// The free space is the newly computed padded average,
// so the desired size is what's live + the free space.
size_t desired_size = current_live + (size_t)_avg_size->padded_average();
desired_size = align_size_up(desired_size, alignment);
// ...and no larger or smaller than our max and min allowed.
desired_size = MAX2(MIN2(desired_size, _max_gen_size), _min_gen_size);
assert(desired_size <= _max_gen_size, "just checking");
const size_t size_before = _virtual_space->committed_size();
if (desired_size == size_before) {
// no change, we're done
return;
}
{
// We'll be growing or shrinking the heap: in either case,
// we need to hold a lock.
MutexLocker x(ExpandHeap_lock);
if (desired_size > size_before) {
const size_t change_bytes = desired_size - size_before;
const size_t aligned_change_bytes =
align_size_up(change_bytes, alignment);
expand_by(aligned_change_bytes);
} else {
// Shrinking
const size_t change_bytes =
size_before - desired_size;
const size_t aligned_change_bytes = align_size_down(change_bytes, alignment);
shrink(aligned_change_bytes);
}
}
// While this code isn't controlled by AdaptiveSizePolicy, it's
// convenient to see all resizing decsions under the same flag.
if (PrintAdaptiveSizePolicy) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
gclog_or_tty->print_cr("AdaptiveSizePolicy::perm generation size: "
"collection: %d "
"(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
heap->total_collections(),
size_before, _virtual_space->committed_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();
}
}
// Return the number of bytes available for resizing down the young
// generation. This is the minimum of
// input "bytes"
// bytes to the minimum young gen size
// bytes to the size currently being used + some small extra
size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
// Allow shrinkage into the current eden but keep eden large enough
// to maintain the minimum young gen size
bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
return align_size_down(bytes, virtual_space()->alignment());
}
size_t ASParNewGeneration::available_to_min_gen() {
assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
return virtual_space()->committed_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::initialize_work() {
_reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
(HeapWord*)virtual_space()->high_boundary());
MemRegion cmr((HeapWord*)virtual_space()->low(),
(HeapWord*)virtual_space()->high());
Universe::heap()->barrier_set()->resize_covered_region(cmr);
if (ZapUnusedHeapArea) {
// Mangle newly committed space immediately because it
// can be done here more simply that after the new
// spaces have been computed.
SpaceMangler::mangle_region(cmr);
}
if (UseNUMA) {
_eden_space = new MutableNUMASpace(virtual_space()->alignment());
} else {
_eden_space = new MutableSpace(virtual_space()->alignment());
}
_from_space = new MutableSpace(virtual_space()->alignment());
_to_space = new MutableSpace(virtual_space()->alignment());
if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
vm_exit_during_initialization("Could not allocate a young gen space");
}
// Allocate the mark sweep views of spaces
_eden_mark_sweep =
new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);
_from_mark_sweep =
new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);
_to_mark_sweep =
new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);
if (_eden_mark_sweep == NULL ||
_from_mark_sweep == NULL ||
_to_mark_sweep == NULL) {
vm_exit_during_initialization("Could not complete allocation"
" of the young generation");
}
// Generation Counters - generation 0, 3 subspaces
_gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);
// Compute maximum space sizes for performance counters
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
size_t alignment = heap->intra_heap_alignment();
size_t size = virtual_space()->reserved_size();
size_t max_survivor_size;
size_t max_eden_size;
if (UseAdaptiveSizePolicy) {
max_survivor_size = size / MinSurvivorRatio;
// round the survivor space size down to the nearest alignment
// and make sure its size is greater than 0.
max_survivor_size = align_size_down(max_survivor_size, alignment);
max_survivor_size = MAX2(max_survivor_size, alignment);
// set the maximum size of eden to be the size of the young gen
// less two times the minimum survivor size. The minimum survivor
// size for UseAdaptiveSizePolicy is one alignment.
max_eden_size = size - 2 * alignment;
} else {
max_survivor_size = size / InitialSurvivorRatio;
// round the survivor space size down to the nearest alignment
// and make sure its size is greater than 0.
max_survivor_size = align_size_down(max_survivor_size, alignment);
max_survivor_size = MAX2(max_survivor_size, alignment);
// set the maximum size of eden to be the size of the young gen
// less two times the survivor size when the generation is 100%
// committed. The minimum survivor size for -UseAdaptiveSizePolicy
// is dependent on the committed portion (current capacity) of the
// generation - the less space committed, the smaller the survivor
// space, possibly as small as an alignment. However, we are interested
// in the case where the young generation is 100% committed, as this
// is the point where eden reachs its maximum size. At this point,
// the size of a survivor space is max_survivor_size.
max_eden_size = size - 2 * max_survivor_size;
}
_eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
_gen_counters);
_from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
_gen_counters);
_to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
_gen_counters);
compute_initial_space_boundaries();
}
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();
}
}
// 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;
}
// 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;
}
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();)
