--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1RootProcessor.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,334 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+
+#include "classfile/stringTable.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "code/codeCache.hpp"
+#include "gc/g1/bufferingOopClosure.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectorPolicy.hpp"
+#include "gc/g1/g1GCPhaseTimes.hpp"
+#include "gc/g1/g1RemSet.inline.hpp"
+#include "gc/g1/g1RootProcessor.hpp"
+#include "memory/allocation.inline.hpp"
+#include "runtime/fprofiler.hpp"
+#include "runtime/mutex.hpp"
+#include "services/management.hpp"
+
+class G1CodeBlobClosure : public CodeBlobClosure {
+ class HeapRegionGatheringOopClosure : public OopClosure {
+ G1CollectedHeap* _g1h;
+ OopClosure* _work;
+ nmethod* _nm;
+
+ template <typename T>
+ void do_oop_work(T* p) {
+ _work->do_oop(p);
+ T oop_or_narrowoop = oopDesc::load_heap_oop(p);
+ if (!oopDesc::is_null(oop_or_narrowoop)) {
+ oop o = oopDesc::decode_heap_oop_not_null(oop_or_narrowoop);
+ HeapRegion* hr = _g1h->heap_region_containing_raw(o);
+ assert(!_g1h->obj_in_cs(o) || hr->rem_set()->strong_code_roots_list_contains(_nm), "if o still in CS then evacuation failed and nm must already be in the remset");
+ hr->add_strong_code_root(_nm);
+ }
+ }
+
+ public:
+ HeapRegionGatheringOopClosure(OopClosure* oc) : _g1h(G1CollectedHeap::heap()), _work(oc), _nm(NULL) {}
+
+ void do_oop(oop* o) {
+ do_oop_work(o);
+ }
+
+ void do_oop(narrowOop* o) {
+ do_oop_work(o);
+ }
+
+ void set_nm(nmethod* nm) {
+ _nm = nm;
+ }
+ };
+
+ HeapRegionGatheringOopClosure _oc;
+public:
+ G1CodeBlobClosure(OopClosure* oc) : _oc(oc) {}
+
+ void do_code_blob(CodeBlob* cb) {
+ nmethod* nm = cb->as_nmethod_or_null();
+ if (nm != NULL) {
+ if (!nm->test_set_oops_do_mark()) {
+ _oc.set_nm(nm);
+ nm->oops_do(&_oc);
+ nm->fix_oop_relocations();
+ }
+ }
+ }
+};
+
+
+void G1RootProcessor::worker_has_discovered_all_strong_classes() {
+ uint n_workers = _g1h->n_par_threads();
+ assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");
+
+ uint new_value = (uint)Atomic::add(1, &_n_workers_discovered_strong_classes);
+ if (new_value == n_workers) {
+ // This thread is last. Notify the others.
+ MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
+ _lock.notify_all();
+ }
+}
+
+void G1RootProcessor::wait_until_all_strong_classes_discovered() {
+ uint n_workers = _g1h->n_par_threads();
+ assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");
+
+ if ((uint)_n_workers_discovered_strong_classes != n_workers) {
+ MonitorLockerEx ml(&_lock, Mutex::_no_safepoint_check_flag);
+ while ((uint)_n_workers_discovered_strong_classes != n_workers) {
+ _lock.wait(Mutex::_no_safepoint_check_flag, 0, false);
+ }
+ }
+}
+
+G1RootProcessor::G1RootProcessor(G1CollectedHeap* g1h) :
+ _g1h(g1h),
+ _process_strong_tasks(new SubTasksDone(G1RP_PS_NumElements)),
+ _srs(),
+ _lock(Mutex::leaf, "G1 Root Scanning barrier lock", false, Monitor::_safepoint_check_never),
+ _n_workers_discovered_strong_classes(0) {}
+
+void G1RootProcessor::evacuate_roots(OopClosure* scan_non_heap_roots,
+ OopClosure* scan_non_heap_weak_roots,
+ CLDClosure* scan_strong_clds,
+ CLDClosure* scan_weak_clds,
+ bool trace_metadata,
+ uint worker_i) {
+ // First scan the shared roots.
+ double ext_roots_start = os::elapsedTime();
+ G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times();
+
+ BufferingOopClosure buf_scan_non_heap_roots(scan_non_heap_roots);
+ BufferingOopClosure buf_scan_non_heap_weak_roots(scan_non_heap_weak_roots);
+
+ OopClosure* const weak_roots = &buf_scan_non_heap_weak_roots;
+ OopClosure* const strong_roots = &buf_scan_non_heap_roots;
+
+ // CodeBlobClosures are not interoperable with BufferingOopClosures
+ G1CodeBlobClosure root_code_blobs(scan_non_heap_roots);
+
+ process_java_roots(strong_roots,
+ trace_metadata ? scan_strong_clds : NULL,
+ scan_strong_clds,
+ trace_metadata ? NULL : scan_weak_clds,
+ &root_code_blobs,
+ phase_times,
+ worker_i);
+
+ // This is the point where this worker thread will not find more strong CLDs/nmethods.
+ // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
+ if (trace_metadata) {
+ worker_has_discovered_all_strong_classes();
+ }
+
+ process_vm_roots(strong_roots, weak_roots, phase_times, worker_i);
+
+ {
+ // Now the CM ref_processor roots.
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CMRefRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_refProcessor_oops_do)) {
+ // We need to treat the discovered reference lists of the
+ // concurrent mark ref processor as roots and keep entries
+ // (which are added by the marking threads) on them live
+ // until they can be processed at the end of marking.
+ _g1h->ref_processor_cm()->weak_oops_do(&buf_scan_non_heap_roots);
+ }
+ }
+
+ if (trace_metadata) {
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WaitForStrongCLD, worker_i);
+ // Barrier to make sure all workers passed
+ // the strong CLD and strong nmethods phases.
+ wait_until_all_strong_classes_discovered();
+ }
+
+ // Now take the complement of the strong CLDs.
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::WeakCLDRoots, worker_i);
+ ClassLoaderDataGraph::roots_cld_do(NULL, scan_weak_clds);
+ } else {
+ phase_times->record_time_secs(G1GCPhaseTimes::WaitForStrongCLD, worker_i, 0.0);
+ phase_times->record_time_secs(G1GCPhaseTimes::WeakCLDRoots, worker_i, 0.0);
+ }
+
+ // Finish up any enqueued closure apps (attributed as object copy time).
+ buf_scan_non_heap_roots.done();
+ buf_scan_non_heap_weak_roots.done();
+
+ double obj_copy_time_sec = buf_scan_non_heap_roots.closure_app_seconds()
+ + buf_scan_non_heap_weak_roots.closure_app_seconds();
+
+ phase_times->record_time_secs(G1GCPhaseTimes::ObjCopy, worker_i, obj_copy_time_sec);
+
+ double ext_root_time_sec = os::elapsedTime() - ext_roots_start - obj_copy_time_sec;
+
+ phase_times->record_time_secs(G1GCPhaseTimes::ExtRootScan, worker_i, ext_root_time_sec);
+
+ // During conc marking we have to filter the per-thread SATB buffers
+ // to make sure we remove any oops into the CSet (which will show up
+ // as implicitly live).
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SATBFiltering, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_filter_satb_buffers) && _g1h->mark_in_progress()) {
+ JavaThread::satb_mark_queue_set().filter_thread_buffers();
+ }
+ }
+
+ _process_strong_tasks->all_tasks_completed();
+}
+
+void G1RootProcessor::process_strong_roots(OopClosure* oops,
+ CLDClosure* clds,
+ CodeBlobClosure* blobs) {
+
+ process_java_roots(oops, clds, clds, NULL, blobs, NULL, 0);
+ process_vm_roots(oops, NULL, NULL, 0);
+
+ _process_strong_tasks->all_tasks_completed();
+}
+
+void G1RootProcessor::process_all_roots(OopClosure* oops,
+ CLDClosure* clds,
+ CodeBlobClosure* blobs) {
+
+ process_java_roots(oops, NULL, clds, clds, NULL, NULL, 0);
+ process_vm_roots(oops, oops, NULL, 0);
+
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_CodeCache_oops_do)) {
+ CodeCache::blobs_do(blobs);
+ }
+
+ _process_strong_tasks->all_tasks_completed();
+}
+
+void G1RootProcessor::process_java_roots(OopClosure* strong_roots,
+ CLDClosure* thread_stack_clds,
+ CLDClosure* strong_clds,
+ CLDClosure* weak_clds,
+ CodeBlobClosure* strong_code,
+ G1GCPhaseTimes* phase_times,
+ uint worker_i) {
+ assert(thread_stack_clds == NULL || weak_clds == NULL, "There is overlap between those, only one may be set");
+ // Iterating over the CLDG and the Threads are done early to allow us to
+ // first process the strong CLDs and nmethods and then, after a barrier,
+ // let the thread process the weak CLDs and nmethods.
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::CLDGRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_ClassLoaderDataGraph_oops_do)) {
+ ClassLoaderDataGraph::roots_cld_do(strong_clds, weak_clds);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i);
+ bool is_par = _g1h->n_par_threads() > 0;
+ Threads::possibly_parallel_oops_do(is_par, strong_roots, thread_stack_clds, strong_code);
+ }
+}
+
+void G1RootProcessor::process_vm_roots(OopClosure* strong_roots,
+ OopClosure* weak_roots,
+ G1GCPhaseTimes* phase_times,
+ uint worker_i) {
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::UniverseRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_Universe_oops_do)) {
+ Universe::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JNIRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_JNIHandles_oops_do)) {
+ JNIHandles::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ObjectSynchronizerRoots, worker_i);
+ if (!_process_strong_tasks-> is_task_claimed(G1RP_PS_ObjectSynchronizer_oops_do)) {
+ ObjectSynchronizer::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::FlatProfilerRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_FlatProfiler_oops_do)) {
+ FlatProfiler::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ManagementRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_Management_oops_do)) {
+ Management::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::JVMTIRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_jvmti_oops_do)) {
+ JvmtiExport::oops_do(strong_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::SystemDictionaryRoots, worker_i);
+ if (!_process_strong_tasks->is_task_claimed(G1RP_PS_SystemDictionary_oops_do)) {
+ SystemDictionary::roots_oops_do(strong_roots, weak_roots);
+ }
+ }
+
+ {
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::StringTableRoots, worker_i);
+ // All threads execute the following. A specific chunk of buckets
+ // from the StringTable are the individual tasks.
+ if (weak_roots != NULL) {
+ StringTable::possibly_parallel_oops_do(weak_roots);
+ }
+ }
+}
+
+void G1RootProcessor::scan_remembered_sets(G1ParPushHeapRSClosure* scan_rs,
+ OopClosure* scan_non_heap_weak_roots,
+ uint worker_i) {
+ G1CodeBlobClosure scavenge_cs_nmethods(scan_non_heap_weak_roots);
+
+ _g1h->g1_rem_set()->oops_into_collection_set_do(scan_rs, &scavenge_cs_nmethods, worker_i);
+}
+
+void G1RootProcessor::set_num_workers(uint active_workers) {
+ _process_strong_tasks->set_n_threads(active_workers);
+}