src/hotspot/share/gc/cms/cmsHeap.cpp
changeset 47622 817f2a7019e4
child 47636 52d46d7e3454
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/cms/cmsHeap.cpp	Thu Oct 12 15:08:19 2017 +0200
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2017, 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 "gc/cms/concurrentMarkSweepThread.hpp"
+#include "gc/cms/cmsHeap.hpp"
+#include "gc/cms/vmCMSOperations.hpp"
+#include "gc/shared/genOopClosures.inline.hpp"
+#include "gc/shared/strongRootsScope.hpp"
+#include "gc/shared/workgroup.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/vmThread.hpp"
+#include "utilities/stack.inline.hpp"
+
+CMSHeap::CMSHeap(GenCollectorPolicy *policy) : GenCollectedHeap(policy) {
+  _workers = new WorkGang("GC Thread", ParallelGCThreads,
+                          /* are_GC_task_threads */true,
+                          /* are_ConcurrentGC_threads */false);
+  _workers->initialize_workers();
+}
+
+jint CMSHeap::initialize() {
+  jint status = GenCollectedHeap::initialize();
+  if (status != JNI_OK) return status;
+
+  // If we are running CMS, create the collector responsible
+  // for collecting the CMS generations.
+  assert(collector_policy()->is_concurrent_mark_sweep_policy(), "must be CMS policy");
+  create_cms_collector();
+
+  return JNI_OK;
+}
+
+void CMSHeap::check_gen_kinds() {
+  assert(young_gen()->kind() == Generation::ParNew,
+         "Wrong youngest generation type");
+  assert(old_gen()->kind() == Generation::ConcurrentMarkSweep,
+         "Wrong generation kind");
+}
+
+CMSHeap* CMSHeap::heap() {
+  CollectedHeap* heap = Universe::heap();
+  assert(heap != NULL, "Uninitialized access to CMSHeap::heap()");
+  assert(heap->kind() == CollectedHeap::CMSHeap, "Not a CMSHeap");
+  return (CMSHeap*) heap;
+}
+
+void CMSHeap::gc_threads_do(ThreadClosure* tc) const {
+  assert(workers() != NULL, "should have workers here");
+  workers()->threads_do(tc);
+  ConcurrentMarkSweepThread::threads_do(tc);
+}
+
+void CMSHeap::print_gc_threads_on(outputStream* st) const {
+  assert(workers() != NULL, "should have workers here");
+  workers()->print_worker_threads_on(st);
+  ConcurrentMarkSweepThread::print_all_on(st);
+}
+
+void CMSHeap::print_on_error(outputStream* st) const {
+  GenCollectedHeap::print_on_error(st);
+  st->cr();
+  CMSCollector::print_on_error(st);
+}
+
+void CMSHeap::create_cms_collector() {
+  assert(old_gen()->kind() == Generation::ConcurrentMarkSweep,
+         "Unexpected generation kinds");
+  assert(gen_policy()->is_concurrent_mark_sweep_policy(), "Unexpected policy type");
+  CMSCollector* collector =
+    new CMSCollector((ConcurrentMarkSweepGeneration*) old_gen(),
+                     rem_set(),
+                     gen_policy()->as_concurrent_mark_sweep_policy());
+
+  if (!collector->completed_initialization()) {
+    vm_shutdown_during_initialization("Could not create CMS collector");
+  }
+}
+
+void CMSHeap::collect(GCCause::Cause cause) {
+  if (should_do_concurrent_full_gc(cause)) {
+    // Mostly concurrent full collection.
+    collect_mostly_concurrent(cause);
+  } else {
+    GenCollectedHeap::collect(cause);
+  }
+}
+
+bool CMSHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
+  switch (cause) {
+    case GCCause::_gc_locker:           return GCLockerInvokesConcurrent;
+    case GCCause::_java_lang_system_gc:
+    case GCCause::_dcmd_gc_run:         return ExplicitGCInvokesConcurrent;
+    default:                            return false;
+  }
+}
+
+void CMSHeap::collect_mostly_concurrent(GCCause::Cause cause) {
+  assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
+
+  MutexLocker ml(Heap_lock);
+  // Read the GC counts while holding the Heap_lock
+  unsigned int full_gc_count_before = total_full_collections();
+  unsigned int gc_count_before      = total_collections();
+  {
+    MutexUnlocker mu(Heap_lock);
+    VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
+    VMThread::execute(&op);
+  }
+}
+
+void CMSHeap::stop() {
+  ConcurrentMarkSweepThread::cmst()->stop();
+}
+
+void CMSHeap::cms_process_roots(StrongRootsScope* scope,
+                                bool young_gen_as_roots,
+                                ScanningOption so,
+                                bool only_strong_roots,
+                                OopsInGenClosure* root_closure,
+                                CLDClosure* cld_closure) {
+  MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations);
+  OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
+  CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
+
+  process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
+  if (!only_strong_roots) {
+    process_string_table_roots(scope, root_closure);
+  }
+
+  if (young_gen_as_roots &&
+      !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
+    root_closure->set_generation(young_gen());
+    young_gen()->oop_iterate(root_closure);
+    root_closure->reset_generation();
+  }
+
+  _process_strong_tasks->all_tasks_completed(scope->n_threads());
+}
+
+void CMSHeap::gc_prologue(bool full) {
+  always_do_update_barrier = false;
+  GenCollectedHeap::gc_prologue(full);
+};
+
+void CMSHeap::gc_epilogue(bool full) {
+  GenCollectedHeap::gc_epilogue(full);
+  always_do_update_barrier = true;
+};