1 /*
   2  * Copyright (c) 2019, Red Hat, Inc. All rights reserved.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #include "precompiled.hpp"
  25 
  26 #include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp"
  27 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
  28 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
  29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  30 #include "gc/shenandoah/shenandoahLock.hpp"
  31 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
  32 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
  33 #include "memory/iterator.hpp"
  34 #include "memory/resourceArea.hpp"
  35 
  36 bool ShenandoahBarrierSetNMethod::nmethod_entry_barrier(nmethod* nm) {
  37   ShenandoahReentrantLock* lock = ShenandoahNMethod::lock_for_nmethod(nm);
  38   assert(lock != NULL, "Must be");
  39   ShenandoahReentrantLocker locker(lock);
  40 
  41   if (!is_armed(nm)) {
  42     // Some other thread got here first and healed the oops
  43     // and disarmed the nmethod.
  44     return true;
  45   }
  46 
  47   if (nm->is_unloading()) {
  48     // We don't need to take the lock when unlinking nmethods from
  49     // the Method, because it is only concurrently unlinked by
  50     // the entry barrier, which acquires the per nmethod lock.
  51     nm->unlink_from_method(false /* acquire_lock */);
  52 
  53     // We can end up calling nmethods that are unloading
  54     // since we clear compiled ICs lazily. Returning false
  55     // will re-resovle the call and update the compiled IC.
  56     return false;
  57   }
  58 
  59   // Heal oops and disarm
  60   ShenandoahEvacOOMScope scope;
  61   ShenandoahNMethod::heal_nmethod(nm);
  62   ShenandoahNMethod::disarm_nmethod(nm);
  63   return true;
  64 }
  65 
  66 
  67 int ShenandoahBarrierSetNMethod::disarmed_value() const {
  68   return ShenandoahCodeRoots::disarmed_value();
  69 }
  70 
  71 ByteSize ShenandoahBarrierSetNMethod::thread_disarmed_offset() const {
  72   return ShenandoahThreadLocalData::disarmed_value_offset();
  73 }