rev 53848 : 8219469: ZGC: Extract functions out from ZNMethodTable into new ZNMethod class

   1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "classfile/classLoaderDataGraph.hpp"
  26 #include "classfile/systemDictionary.hpp"
  27 #include "code/codeBehaviours.hpp"
  28 #include "code/codeCache.hpp"
  29 #include "code/dependencyContext.hpp"
  30 #include "gc/shared/gcBehaviours.hpp"
  31 #include "gc/shared/suspendibleThreadSet.hpp"
  32 #include "gc/z/zLock.inline.hpp"
  33 #include "gc/z/zNMethodTable.hpp"
  34 #include "gc/z/zOopClosures.hpp"
  35 #include "gc/z/zStat.hpp"
  36 #include "gc/z/zUnload.hpp"
  37 #include "oops/access.inline.hpp"
  38 
  39 static const ZStatSubPhase ZSubPhaseConcurrentClassesUnload("Concurrent Classes Unload");
  40 
  41 class ZIsUnloadingOopClosure : public OopClosure {
  42 private:
  43   ZPhantomIsAliveObjectClosure _is_alive;
  44   bool                         _is_unloading;
  45 
  46 public:
  47   ZIsUnloadingOopClosure() :
  48       _is_alive(),
  49       _is_unloading(false) {}
  50 
  51   virtual void do_oop(oop* p) {
  52     const oop o = RawAccess<>::oop_load(p);
  53     if (o != NULL && !_is_alive.do_object_b(o)) {
  54       _is_unloading = true;
  55     }
  56   }
  57 
  58   virtual void do_oop(narrowOop* p) {
  59     ShouldNotReachHere();
  60   }
  61 
  62   bool is_unloading() const {
  63     return _is_unloading;
  64   }
  65 };
  66 
  67 class ZIsUnloadingBehaviour : public IsUnloadingBehaviour {
  68 private:
  69   bool is_unloading(nmethod* nm) const {
  70     ZIsUnloadingOopClosure cl;
  71     nm->oops_do(&cl, true /* allow_zombie */);
  72     return cl.is_unloading();
  73   }
  74 
  75 public:
  76   virtual bool is_unloading(CompiledMethod* method) const {
  77     nmethod* const nm = method->as_nmethod();
  78     ZReentrantLock* const lock = ZNMethodTable::lock_for_nmethod(nm);
  79     if (lock == NULL) {
  80       return is_unloading(nm);
  81     } else {
  82       ZLocker<ZReentrantLock> locker(lock);
  83       return is_unloading(nm);
  84     }
  85   }
  86 };
  87 
  88 class ZCompiledICProtectionBehaviour : public CompiledICProtectionBehaviour {
  89 public:
  90   virtual bool lock(CompiledMethod* method) {
  91     nmethod* const nm = method->as_nmethod();
  92     ZReentrantLock* const lock = ZNMethodTable::lock_for_nmethod(nm);
  93     if (lock != NULL) {
  94       lock->lock();
  95     }
  96     return true;
  97   }
  98 
  99   virtual void unlock(CompiledMethod* method) {
 100     nmethod* const nm = method->as_nmethod();
 101     ZReentrantLock* const lock = ZNMethodTable::lock_for_nmethod(nm);
 102     if (lock != NULL) {
 103       lock->unlock();
 104     }
 105   }
 106 
 107   virtual bool is_safe(CompiledMethod* method) {
 108     if (SafepointSynchronize::is_at_safepoint()) {
 109       return true;
 110     }
 111 
 112     nmethod* const nm = method->as_nmethod();
 113     ZReentrantLock* const lock = ZNMethodTable::lock_for_nmethod(nm);
 114     return lock == NULL || lock->is_owned();
 115   }
 116 };
 117 
 118 ZUnload::ZUnload(ZWorkers* workers) :
 119     _workers(workers) {
 120 
 121   if (!ClassUnloading) {
 122     return;
 123   }
 124 
 125   static ZIsUnloadingBehaviour is_unloading_behaviour;
 126   IsUnloadingBehaviour::set_current(&is_unloading_behaviour);
 127 
 128   static ZCompiledICProtectionBehaviour ic_protection_behaviour;
 129   CompiledICProtectionBehaviour::set_current(&ic_protection_behaviour);
 130 }
 131 
 132 void ZUnload::prepare() {
 133   if (!ClassUnloading) {
 134     return;
 135   }
 136 
 137   CodeCache::increment_unloading_cycle();
 138   DependencyContext::cleaning_start();
 139 }
 140 
 141 void ZUnload::unlink() {
 142   SuspendibleThreadSetJoiner sts;
 143   bool unloading_occurred;
 144 
 145   {
 146     MutexLockerEx ml(ClassLoaderDataGraph_lock);
 147     unloading_occurred = SystemDictionary::do_unloading(ZStatPhase::timer());
 148   }
 149 
 150   Klass::clean_weak_klass_links(unloading_occurred);
 151 
 152   ZNMethodTable::unlink(_workers, unloading_occurred);
 153 
 154   DependencyContext::cleaning_end();
 155 }
 156 
 157 void ZUnload::purge() {
 158   {
 159     SuspendibleThreadSetJoiner sts;
 160     ZNMethodTable::purge(_workers);
 161   }
 162 
 163   ClassLoaderDataGraph::purge();
 164   CodeCache::purge_exception_caches();
 165 }
 166 
 167 class ZUnloadRendezvousClosure : public ThreadClosure {
 168 public:
 169   void do_thread(Thread* thread) {}
 170 };
 171 
 172 void ZUnload::unload() {
 173   if (!ClassUnloading) {
 174     return;
 175   }
 176 
 177   ZStatTimer timer(ZSubPhaseConcurrentClassesUnload);
 178 
 179   // Unlink stale metadata and nmethods
 180   unlink();
 181 
 182   // Make sure stale metadata and nmethods are no longer observable
 183   ZUnloadRendezvousClosure cl;
 184   Handshake::execute(&cl);
 185 
 186   // Purge stale metadata and nmethods that were unlinked
 187   purge();
 188 }
 189 
 190 void ZUnload::finish() {
 191   // Resize and verify metaspace
 192   MetaspaceGC::compute_new_size();
 193   MetaspaceUtils::verify_metrics();
 194 }
--- EOF ---