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src/share/vm/gc_implementation/shared/suspendibleThreadSet.hpp

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rev 8331 : 8079579: Add SuspendibleThreadSetLeaver and make SuspendibleThreadSet::joint()/leave() private
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   1 /*
   2  * Copyright (c) 2014, 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_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 // A SuspendibleThreadSet is a set of threads that can be suspended.
  31 // A thread can join and later leave the set, and periodically yield.
  32 // If some thread (not in the set) requests, via synchronize(), that
  33 // the threads be suspended, then the requesting thread is blocked
  34 // until all the threads in the set have yielded or left the set. Threads
  35 // may not enter the set when an attempted suspension is in progress. The
  36 // suspending thread later calls desynchronize(), allowing the suspended
  37 // threads to continue.
  38 class SuspendibleThreadSet : public AllStatic {



  39 private:
  40   static uint   _nthreads;
  41   static uint   _nthreads_stopped;
  42   static bool   _suspend_all;
  43   static double _suspend_all_start;
  44 
  45 public:
  46   // Add the current thread to the set. May block if a suspension is in progress.
  47   static void join();
  48 
  49   // Removes the current thread from the set.
  50   static void leave();
  51 

  52   // Returns true if an suspension is in progress.
  53   static bool should_yield() { return _suspend_all; }
  54 
  55   // Suspends the current thread if a suspension is in progress.
  56   static void yield();
  57 
  58   // Returns when all threads in the set are suspended.
  59   static void synchronize();
  60 
  61   // Resumes all suspended threads in the set.
  62   static void desynchronize();
  63 };
  64 
  65 class SuspendibleThreadSetJoiner : public StackObj {



  66 public:
  67   SuspendibleThreadSetJoiner() {

  68     SuspendibleThreadSet::join();
  69   }

  70 
  71   ~SuspendibleThreadSetJoiner() {

  72     SuspendibleThreadSet::leave();
  73   }

  74 
  75   bool should_yield() {

  76     return SuspendibleThreadSet::should_yield();



  77   }
  78 
  79   void yield() {

  80     SuspendibleThreadSet::yield();


















  81   }
  82 };
  83 
  84 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
   1 /*
   2  * Copyright (c) 2014, 2015, 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_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 // A SuspendibleThreadSet is a set of threads that can be suspended.
  31 // A thread can join and later leave the set, and periodically yield.
  32 // If some thread (not in the set) requests, via synchronize(), that
  33 // the threads be suspended, then the requesting thread is blocked
  34 // until all the threads in the set have yielded or left the set. Threads
  35 // may not enter the set when an attempted suspension is in progress. The
  36 // suspending thread later calls desynchronize(), allowing the suspended
  37 // threads to continue.
  38 class SuspendibleThreadSet : public AllStatic {
  39   friend class SuspendibleThreadSetJoiner;
  40   friend class SuspendibleThreadSetLeaver;
  41 
  42 private:
  43   static uint   _nthreads;
  44   static uint   _nthreads_stopped;
  45   static bool   _suspend_all;
  46   static double _suspend_all_start;
  47 

  48   // Add the current thread to the set. May block if a suspension is in progress.
  49   static void join();
  50 
  51   // Removes the current thread from the set.
  52   static void leave();
  53 
  54 public:
  55   // Returns true if an suspension is in progress.
  56   static bool should_yield() { return _suspend_all; }
  57 
  58   // Suspends the current thread if a suspension is in progress.
  59   static void yield();
  60 
  61   // Returns when all threads in the set are suspended.
  62   static void synchronize();
  63 
  64   // Resumes all suspended threads in the set.
  65   static void desynchronize();
  66 };
  67 
  68 class SuspendibleThreadSetJoiner : public StackObj {
  69 private:
  70   bool _active;
  71 
  72 public:
  73   SuspendibleThreadSetJoiner(bool active = true) : _active(active) {
  74     if (_active) {
  75       SuspendibleThreadSet::join();
  76     }
  77   }
  78 
  79   ~SuspendibleThreadSetJoiner() {
  80     if (_active) {
  81       SuspendibleThreadSet::leave();
  82     }
  83   }
  84 
  85   bool should_yield() {
  86     if (_active) {
  87       return SuspendibleThreadSet::should_yield();
  88     } else {
  89       return false;
  90     }
  91   }
  92 
  93   void yield() {
  94     assert(_active, "Thread has not joined the suspendible thread set");
  95     SuspendibleThreadSet::yield();
  96   }
  97 };
  98 
  99 class SuspendibleThreadSetLeaver : public StackObj {
 100 private:
 101   bool _active;
 102 
 103 public:
 104   SuspendibleThreadSetLeaver(bool active = true) : _active(active) {
 105     if (_active) {
 106       SuspendibleThreadSet::leave();
 107     }
 108   }
 109 
 110   ~SuspendibleThreadSetLeaver() {
 111     if (_active) {
 112       SuspendibleThreadSet::join();
 113     }
 114   }
 115 };
 116 
 117 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_SUSPENDIBLETHREADSET_HPP
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