diff -r e45861098f5a -r fec48bf5a827 hotspot/src/share/vm/gc/g1/g1RootProcessor.cpp --- /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 + 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); +}