1 /*
   2  * Copyright (c) 2000, 2012, 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 
  25 #ifndef SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP
  26 #define SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP
  27 
  28 #include "memory/gcLocker.hpp"
  29 
  30 inline bool GC_locker::is_active() {
  31   assert(_needs_gc || SafepointSynchronize::is_at_safepoint(), "only read at safepoint");
  32   verify_critical_count();
  33   return _lock_count > 0 || _jni_lock_count > 0;
  34 }
  35 
  36 inline void GC_locker::lock() {
  37   // cast away volatile
  38   Atomic::inc(&_lock_count);
  39   CHECK_UNHANDLED_OOPS_ONLY(
  40     if (CheckUnhandledOops) { Thread::current()->_gc_locked_out_count++; })
  41   assert(Universe::heap() == NULL ||
  42          !Universe::heap()->is_gc_active(), "locking failed");
  43 }
  44 
  45 inline void GC_locker::unlock() {
  46   // cast away volatile
  47   Atomic::dec(&_lock_count);
  48   CHECK_UNHANDLED_OOPS_ONLY(
  49     if (CheckUnhandledOops) { Thread::current()->_gc_locked_out_count--; })
  50 }
  51 
  52 inline void GC_locker::lock_critical(JavaThread* thread) {
  53   if (!thread->in_critical()) {
  54     if (needs_gc()) {
  55       // jni_lock call calls enter_critical under the lock so that the
  56       // global lock count and per thread count are in agreement.
  57       jni_lock(thread);
  58       return;
  59     }
  60     increment_debug_jni_lock_count();
  61   }
  62   thread->enter_critical();
  63 }
  64 
  65 inline void GC_locker::unlock_critical(JavaThread* thread) {
  66   if (thread->in_last_critical()) {
  67     if (needs_gc()) {
  68       // jni_unlock call calls exit_critical under the lock so that
  69       // the global lock count and per thread count are in agreement.
  70       jni_unlock(thread);
  71       return;
  72     }
  73     decrement_debug_jni_lock_count();
  74   }
  75   thread->exit_critical();
  76 }
  77 
  78 #endif // SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP