void VM_GenCollectFull::doit() {
SvcGCMarker sgcm(SvcGCMarker::FULL);
GenCollectedHeap* gch = GenCollectedHeap::heap();
GCCauseSetter gccs(gch, _gc_cause);
gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);
}
void VM_GenCollectForPermanentAllocation::doit() {
SvcGCMarker sgcm(SvcGCMarker::FULL);
SharedHeap* heap = (SharedHeap*)Universe::heap();
GCCauseSetter gccs(heap, _gc_cause);
switch (heap->kind()) {
case (CollectedHeap::GenCollectedHeap): {
GenCollectedHeap* gch = (GenCollectedHeap*)heap;
gch->do_full_collection(gch->must_clear_all_soft_refs(),
gch->n_gens() - 1);
break;
}
#ifndef SERIALGC
case (CollectedHeap::G1CollectedHeap): {
G1CollectedHeap* g1h = (G1CollectedHeap*)heap;
g1h->do_full_collection(_gc_cause == GCCause::_last_ditch_collection);
break;
}
#endif // SERIALGC
default:
ShouldNotReachHere();
}
_res = heap->perm_gen()->allocate(_size, false);
assert(heap->is_in_reserved_or_null(_res), "result not in heap");
if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
set_gc_locked();
}
}
void VM_GenCollectForAllocation::doit() {
SvcGCMarker sgcm(SvcGCMarker::MINOR);
GenCollectedHeap* gch = GenCollectedHeap::heap();
GCCauseSetter gccs(gch, _gc_cause);
_res = gch->satisfy_failed_allocation(_size, _tlab);
assert(gch->is_in_reserved_or_null(_res), "result not in heap");
if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
set_gc_locked();
}
}
void VM_CollectForMetadataAllocation::doit() {
SvcGCMarker sgcm(SvcGCMarker::FULL);
CollectedHeap* heap = Universe::heap();
GCCauseSetter gccs(heap, _gc_cause);
// Check again if the space is available. Another thread
// may have similarly failed a metadata allocation and induced
// a GC that freed space for the allocation.
if (!MetadataAllocationFailALot) {
_result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype);
}
if (_result == NULL) {
if (UseConcMarkSweepGC) {
if (CMSClassUnloadingEnabled) {
MetaspaceGC::set_should_concurrent_collect(true);
}
// For CMS expand since the collection is going to be concurrent.
_result =
_loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype);
}
if (_result == NULL) {
// Don't clear the soft refs yet.
if (Verbose && PrintGCDetails && UseConcMarkSweepGC) {
gclog_or_tty->print_cr("\nCMS full GC for Metaspace");
}
heap->collect_as_vm_thread(GCCause::_metadata_GC_threshold);
// After a GC try to allocate without expanding. Could fail
// and expansion will be tried below.
_result =
_loader_data->metaspace_non_null()->allocate(_size, _mdtype);
}
if (_result == NULL) {
// If still failing, allow the Metaspace to expand.
// See delta_capacity_until_GC() for explanation of the
// amount of the expansion.
// This should work unless there really is no more space
// or a MaxMetaspaceSize has been specified on the command line.
_result =
_loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype);
if (_result == NULL) {
// If expansion failed, do a last-ditch collection and try allocating
// again. A last-ditch collection will clear softrefs. This
// behavior is similar to the last-ditch collection done for perm
// gen when it was full and a collection for failed allocation
// did not free perm gen space.
heap->collect_as_vm_thread(GCCause::_last_ditch_collection);
_result =
_loader_data->metaspace_non_null()->allocate(_size, _mdtype);
}
}
if (Verbose && PrintGCDetails && _result == NULL) {
gclog_or_tty->print_cr("\nAfter Metaspace GC failed to allocate size "
SIZE_FORMAT, _size);
}
}
if (_result == NULL && GC_locker::is_active_and_needs_gc()) {
set_gc_locked();
}
}
void ConcurrentMarkThread::run() {
initialize_in_thread();
_vtime_start = os::elapsedVTime();
wait_for_universe_init();
G1CollectedHeap* g1h = G1CollectedHeap::heap();
G1CollectorPolicy* g1_policy = g1h->g1_policy();
G1MMUTracker *mmu_tracker = g1_policy->mmu_tracker();
Thread *current_thread = Thread::current();
while (!_should_terminate) {
// wait until started is set.
sleepBeforeNextCycle();
{
ResourceMark rm;
HandleMark hm;
SvcGCMarker sgcm(SvcGCMarker::OTHER); // <underscore>
gclog_or_tty->print_cr("Sending GC start event (underscore)");
double cycle_start = os::elapsedVTime();
// We have to ensure that we finish scanning the root regions
// before the next GC takes place. To ensure this we have to
// make sure that we do not join the STS until the root regions
// have been scanned. If we did then it's possible that a
// subsequent GC could block us from joining the STS and proceed
// without the root regions have been scanned which would be a
// correctness issue.
double scan_start = os::elapsedTime();
if (!cm()->has_aborted()) {
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-root-region-scan-start]");
}
_cm->scanRootRegions();
double scan_end = os::elapsedTime();
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-root-region-scan-end, %1.7lf secs]",
scan_end - scan_start);
}
}
double mark_start_sec = os::elapsedTime();
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-mark-start]");
}
int iter = 0;
do {
iter++;
if (!cm()->has_aborted()) {
_cm->markFromRoots();
}
double mark_end_time = os::elapsedVTime();
double mark_end_sec = os::elapsedTime();
_vtime_mark_accum += (mark_end_time - cycle_start);
if (!cm()->has_aborted()) {
if (g1_policy->adaptive_young_list_length()) {
double now = os::elapsedTime();
double remark_prediction_ms = g1_policy->predict_remark_time_ms();
jlong sleep_time_ms = mmu_tracker->when_ms(now, remark_prediction_ms);
os::sleep(current_thread, sleep_time_ms, false);
}
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-mark-end, %1.7lf secs]",
mark_end_sec - mark_start_sec);
}
CMCheckpointRootsFinalClosure final_cl(_cm);
VM_CGC_Operation op(&final_cl, "GC remark", true /* needs_pll */);
VMThread::execute(&op);
}
if (cm()->restart_for_overflow()) {
if (G1TraceMarkStackOverflow) {
gclog_or_tty->print_cr("Restarting conc marking because of MS overflow "
"in remark (restart #%d).", iter);
}
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-mark-restart-for-overflow]");
}
}
} while (cm()->restart_for_overflow());
double end_time = os::elapsedVTime();
// Update the total virtual time before doing this, since it will try
// to measure it to get the vtime for this marking. We purposely
// neglect the presumably-short "completeCleanup" phase here.
_vtime_accum = (end_time - _vtime_start);
if (!cm()->has_aborted()) {
if (g1_policy->adaptive_young_list_length()) {
double now = os::elapsedTime();
double cleanup_prediction_ms = g1_policy->predict_cleanup_time_ms();
jlong sleep_time_ms = mmu_tracker->when_ms(now, cleanup_prediction_ms);
os::sleep(current_thread, sleep_time_ms, false);
}
CMCleanUp cl_cl(_cm);
VM_CGC_Operation op(&cl_cl, "GC cleanup", false /* needs_pll */);
VMThread::execute(&op);
} else {
// We don't want to update the marking status if a GC pause
// is already underway.
_sts.join();
g1h->set_marking_complete();
_sts.leave();
}
// Check if cleanup set the free_regions_coming flag. If it
// hasn't, we can just skip the next step.
if (g1h->free_regions_coming()) {
// The following will finish freeing up any regions that we
// found to be empty during cleanup. We'll do this part
// without joining the suspendible set. If an evacuation pause
// takes place, then we would carry on freeing regions in
// case they are needed by the pause. If a Full GC takes
// place, it would wait for us to process the regions
// reclaimed by cleanup.
double cleanup_start_sec = os::elapsedTime();
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-cleanup-start]");
}
// Now do the concurrent cleanup operation.
_cm->completeCleanup();
// Notify anyone who's waiting that there are no more free
// regions coming. We have to do this before we join the STS
// (in fact, we should not attempt to join the STS in the
// interval between finishing the cleanup pause and clearing
// the free_regions_coming flag) otherwise we might deadlock:
// a GC worker could be blocked waiting for the notification
// whereas this thread will be blocked for the pause to finish
// while it's trying to join the STS, which is conditional on
// the GC workers finishing.
g1h->reset_free_regions_coming();
double cleanup_end_sec = os::elapsedTime();
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-cleanup-end, %1.7lf secs]",
cleanup_end_sec - cleanup_start_sec);
}
}
guarantee(cm()->cleanup_list_is_empty(),
"at this point there should be no regions on the cleanup list");
// There is a tricky race before recording that the concurrent
// cleanup has completed and a potential Full GC starting around
// the same time. We want to make sure that the Full GC calls
// abort() on concurrent mark after
// record_concurrent_mark_cleanup_completed(), since abort() is
// the method that will reset the concurrent mark state. If we
// end up calling record_concurrent_mark_cleanup_completed()
// after abort() then we might incorrectly undo some of the work
// abort() did. Checking the has_aborted() flag after joining
// the STS allows the correct ordering of the two methods. There
// are two scenarios:
//
// a) If we reach here before the Full GC, the fact that we have
// joined the STS means that the Full GC cannot start until we
// leave the STS, so record_concurrent_mark_cleanup_completed()
// will complete before abort() is called.
//
// b) If we reach here during the Full GC, we'll be held up from
// joining the STS until the Full GC is done, which means that
// abort() will have completed and has_aborted() will return
// true to prevent us from calling
// record_concurrent_mark_cleanup_completed() (and, in fact, it's
// not needed any more as the concurrent mark state has been
// already reset).
_sts.join();
if (!cm()->has_aborted()) {
g1_policy->record_concurrent_mark_cleanup_completed();
}
_sts.leave();
if (cm()->has_aborted()) {
if (G1Log::fine()) {
gclog_or_tty->date_stamp(PrintGCDateStamps);
gclog_or_tty->stamp(PrintGCTimeStamps);
gclog_or_tty->print_cr("[GC concurrent-mark-abort]");
}
}
// We now want to allow clearing of the marking bitmap to be
// suspended by a collection pause.
_sts.join();
_cm->clearNextBitmap();
_sts.leave();
}
// Update the number of full collections that have been
// completed. This will also notify the FullGCCount_lock in case a
// Java thread is waiting for a full GC to happen (e.g., it
// called System.gc() with +ExplicitGCInvokesConcurrent).
_sts.join();
g1h->increment_old_marking_cycles_completed(true /* concurrent */);
g1h->register_concurrent_cycle_end();
_sts.leave();
}
assert(_should_terminate, "just checking");
terminate();
}