--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shenandoah/shenandoahUnload.cpp Wed Nov 27 11:52:57 2019 -0500
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2019, Red Hat, Inc. All rights reserved.
+ *
+ * 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/classLoaderDataGraph.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "code/codeBehaviours.hpp"
+#include "code/codeCache.hpp"
+#include "code/dependencyContext.hpp"
+#include "gc/shared/gcBehaviours.hpp"
+#include "gc/shared/suspendibleThreadSet.hpp"
+#include "gc/shenandoah/shenandoahClosures.inline.hpp"
+#include "gc/shenandoah/shenandoahCodeRoots.hpp"
+#include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
+#include "gc/shenandoah/shenandoahNMethod.inline.hpp"
+#include "gc/shenandoah/shenandoahLock.hpp"
+#include "gc/shenandoah/shenandoahRootProcessor.hpp"
+#include "gc/shenandoah/shenandoahUnload.hpp"
+#include "gc/shenandoah/shenandoahVerifier.hpp"
+#include "memory/iterator.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/access.inline.hpp"
+
+class ShenandoahIsUnloadingOopClosure : public OopClosure {
+private:
+ ShenandoahMarkingContext* _marking_context;
+ bool _is_unloading;
+
+public:
+ ShenandoahIsUnloadingOopClosure() :
+ _marking_context(ShenandoahHeap::heap()->marking_context()),
+ _is_unloading(false) {
+ }
+
+ virtual void do_oop(oop* p) {
+ if (_is_unloading) {
+ return;
+ }
+
+ const oop o = RawAccess<>::oop_load(p);
+ if (!CompressedOops::is_null(o) &&
+ _marking_context->is_complete() &&
+ !_marking_context->is_marked(o)) {
+ _is_unloading = true;
+ }
+ }
+
+ virtual void do_oop(narrowOop* p) {
+ ShouldNotReachHere();
+ }
+
+ bool is_unloading() const {
+ return _is_unloading;
+ }
+};
+
+class ShenandoahIsUnloadingBehaviour : public IsUnloadingBehaviour {
+public:
+ virtual bool is_unloading(CompiledMethod* method) const {
+ nmethod* const nm = method->as_nmethod();
+ guarantee(ShenandoahHeap::heap()->is_evacuation_in_progress(), "Only this phase");
+ ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
+ ShenandoahReentrantLocker locker(data->lock());
+ ShenandoahIsUnloadingOopClosure cl;
+ data->oops_do(&cl);
+ return cl.is_unloading();
+ }
+};
+
+class ShenandoahCompiledICProtectionBehaviour : public CompiledICProtectionBehaviour {
+public:
+ virtual bool lock(CompiledMethod* method) {
+ nmethod* const nm = method->as_nmethod();
+ ShenandoahReentrantLock* const lock = ShenandoahNMethod::lock_for_nmethod(nm);
+ assert(lock != NULL, "Not yet registered?");
+ lock->lock();
+ return true;
+ }
+
+ virtual void unlock(CompiledMethod* method) {
+ nmethod* const nm = method->as_nmethod();
+ ShenandoahReentrantLock* const lock = ShenandoahNMethod::lock_for_nmethod(nm);
+ assert(lock != NULL, "Not yet registered?");
+ lock->unlock();
+ }
+
+ virtual bool is_safe(CompiledMethod* method) {
+ if (SafepointSynchronize::is_at_safepoint()) {
+ return true;
+ }
+
+ nmethod* const nm = method->as_nmethod();
+ ShenandoahReentrantLock* const lock = ShenandoahNMethod::lock_for_nmethod(nm);
+ assert(lock != NULL, "Not yet registered?");
+ return lock->owned_by_self();
+ }
+};
+
+ShenandoahUnload::ShenandoahUnload() {
+ if (ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) {
+ static ShenandoahIsUnloadingBehaviour is_unloading_behaviour;
+ IsUnloadingBehaviour::set_current(&is_unloading_behaviour);
+
+ static ShenandoahCompiledICProtectionBehaviour ic_protection_behaviour;
+ CompiledICProtectionBehaviour::set_current(&ic_protection_behaviour);
+ }
+}
+
+void ShenandoahUnload::prepare() {
+ assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint");
+ assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), "Sanity");
+ CodeCache::increment_unloading_cycle();
+ DependencyContext::cleaning_start();
+}
+
+void ShenandoahUnload::unlink() {
+ SuspendibleThreadSetJoiner sts;
+ bool unloading_occurred;
+ ShenandoahHeap* const heap = ShenandoahHeap::heap();
+ {
+ MutexLocker cldg_ml(ClassLoaderDataGraph_lock);
+ unloading_occurred = SystemDictionary::do_unloading(heap->gc_timer());
+ }
+
+ Klass::clean_weak_klass_links(unloading_occurred);
+ ShenandoahCodeRoots::unlink(ShenandoahHeap::heap()->workers(), unloading_occurred);
+ DependencyContext::cleaning_end();
+}
+
+void ShenandoahUnload::purge() {
+ {
+ SuspendibleThreadSetJoiner sts;
+ ShenandoahCodeRoots::purge(ShenandoahHeap::heap()->workers());
+ }
+
+ ClassLoaderDataGraph::purge();
+ CodeCache::purge_exception_caches();
+}
+
+class ShenandoahUnloadRendezvousClosure : public ThreadClosure {
+public:
+ void do_thread(Thread* thread) {}
+};
+
+void ShenandoahUnload::unload() {
+ assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), "Why we here?");
+ if (!ShenandoahHeap::heap()->is_evacuation_in_progress()) {
+ return;
+ }
+
+ // Unlink stale metadata and nmethods
+ unlink();
+
+ // Make sure stale metadata and nmethods are no longer observable
+ ShenandoahUnloadRendezvousClosure cl;
+ Handshake::execute(&cl);
+
+ // Purge stale metadata and nmethods that were unlinked
+ purge();
+}
+
+void ShenandoahUnload::finish() {
+ MetaspaceGC::compute_new_size();
+ MetaspaceUtils::verify_metrics();
+}