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src/hotspot/share/gc/shenandoah/shenandoahControlThread.hpp

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 40 class ShenandoahPeriodicTask : public PeriodicTask {
 41 private:
 42   ShenandoahControlThread* _thread;
 43 public:
 44   ShenandoahPeriodicTask(ShenandoahControlThread* thread) :
 45           PeriodicTask(100), _thread(thread) {}
 46   virtual void task();
 47 };
 48 
 49 // Periodic task to notify blocked paced waiters.
 50 class ShenandoahPeriodicPacerNotify : public PeriodicTask {
 51 public:
 52   ShenandoahPeriodicPacerNotify() : PeriodicTask(PeriodicTask::min_interval) {}
 53   virtual void task();
 54 };
 55 
 56 class ShenandoahControlThread: public ConcurrentGCThread {
 57   friend class VMStructs;
 58 
 59 private:
 60   typedef enum {
 61     none,
 62     concurrent_normal,
 63     stw_degenerated,
 64     stw_full
 65   } GCMode;
 66 
 67   // While we could have a single lock for these, it may risk unblocking
 68   // GC waiters when alloc failure GC cycle finishes. We want instead
 69   // to make complete explicit cycle for for demanding customers.
 70   Monitor _alloc_failure_waiters_lock;
 71   Monitor _gc_waiters_lock;

 72   ShenandoahPeriodicTask _periodic_task;
 73   ShenandoahPeriodicPacerNotify _periodic_pacer_notify_task;
 74 
 75 public:








 76   void run_service();
 77   void stop_service();
 78 


 79 private:


 80   ShenandoahSharedFlag _gc_requested;
 81   ShenandoahSharedFlag _alloc_failure_gc;
 82   ShenandoahSharedFlag _graceful_shutdown;
 83   ShenandoahSharedFlag _heap_changed;
 84   ShenandoahSharedFlag _do_counters_update;
 85   ShenandoahSharedFlag _force_counters_update;
 86   GCCause::Cause       _requested_gc_cause;

 87   ShenandoahGC::ShenandoahDegenPoint _degen_point;

 88 
 89   shenandoah_padding(0);
 90   volatile size_t _allocs_seen;
 91   shenandoah_padding(1);
 92   volatile size_t _gc_id;
 93   shenandoah_padding(2);


 94 
 95   bool check_cancellation_or_degen(ShenandoahGC::ShenandoahDegenPoint point);
 96   void service_concurrent_normal_cycle(GCCause::Cause cause);

 97   void service_stw_full_cycle(GCCause::Cause cause);
 98   void service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahGC::ShenandoahDegenPoint point);



 99   void service_uncommit(double shrink_before, size_t shrink_until);
100 
101   bool try_set_alloc_failure_gc();
102   void notify_alloc_failure_waiters();
103   bool is_alloc_failure_gc();
104 
105   void reset_gc_id();
106   void update_gc_id();
107   size_t get_gc_id();
108 
109   void notify_gc_waiters();
110 
111   // Handle GC request.
112   // Blocks until GC is over.
113   void handle_requested_gc(GCCause::Cause cause);
114 
115   bool is_explicit_gc(GCCause::Cause cause) const;



116 
117   bool check_soft_max_changed() const;
118 
119 public:
120   // Constructor
121   ShenandoahControlThread();
122   ~ShenandoahControlThread();
123 
124   // Handle allocation failure from normal allocation.
125   // Blocks until memory is available.
126   void handle_alloc_failure(ShenandoahAllocRequest& req);
127 
128   // Handle allocation failure from evacuation path.
129   // Optionally blocks while collector is handling the failure.
130   void handle_alloc_failure_evac(size_t words);
131 
132   void request_gc(GCCause::Cause cause);

133 
134   void handle_counters_update();
135   void handle_force_counters_update();
136   void set_forced_counters_update(bool value);
137 
138   void notify_heap_changed();
139 
140   void pacing_notify_alloc(size_t words);
141 
142   void start();
143   void prepare_for_graceful_shutdown();
144   bool in_graceful_shutdown();
145 
146   const char* name() const { return "ShenandoahControlThread";}
147 
148   // Printing
149   void print_on(outputStream* st) const;
150   void print() const;
















151 };
152 
153 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCONTROLTHREAD_HPP

 40 class ShenandoahPeriodicTask : public PeriodicTask {
 41 private:
 42   ShenandoahControlThread* _thread;
 43 public:
 44   ShenandoahPeriodicTask(ShenandoahControlThread* thread) :
 45           PeriodicTask(100), _thread(thread) {}
 46   virtual void task();
 47 };
 48 
 49 // Periodic task to notify blocked paced waiters.
 50 class ShenandoahPeriodicPacerNotify : public PeriodicTask {
 51 public:
 52   ShenandoahPeriodicPacerNotify() : PeriodicTask(PeriodicTask::min_interval) {}
 53   virtual void task();
 54 };
 55 
 56 class ShenandoahControlThread: public ConcurrentGCThread {
 57   friend class VMStructs;
 58 
 59 private:







 60   // While we could have a single lock for these, it may risk unblocking
 61   // GC waiters when alloc failure GC cycle finishes. We want instead
 62   // to make complete explicit cycle for for demanding customers.
 63   Monitor _alloc_failure_waiters_lock;
 64   Monitor _gc_waiters_lock;
 65   Monitor _control_lock;
 66   ShenandoahPeriodicTask _periodic_task;
 67   ShenandoahPeriodicPacerNotify _periodic_pacer_notify_task;
 68 
 69 public:
 70   typedef enum {
 71     none,
 72     concurrent_normal,
 73     stw_degenerated,
 74     stw_full,
 75     marking_old
 76   } GCMode;
 77 
 78   void run_service();
 79   void stop_service();
 80 
 81   size_t get_gc_id();
 82 
 83 private:
 84   ShenandoahSharedFlag _allow_old_preemption;
 85   ShenandoahSharedFlag _preemption_requested;
 86   ShenandoahSharedFlag _gc_requested;
 87   ShenandoahSharedFlag _alloc_failure_gc;
 88   ShenandoahSharedFlag _graceful_shutdown;

 89   ShenandoahSharedFlag _do_counters_update;
 90   ShenandoahSharedFlag _force_counters_update;
 91   GCCause::Cause       _requested_gc_cause;
 92   GenerationMode       _requested_generation;
 93   ShenandoahGC::ShenandoahDegenPoint _degen_point;
 94   ShenandoahGeneration* _degen_generation;
 95 
 96   shenandoah_padding(0);
 97   volatile size_t _allocs_seen;
 98   shenandoah_padding(1);
 99   volatile size_t _gc_id;
100   shenandoah_padding(2);
101   volatile GCMode _mode;
102   shenandoah_padding(3);
103 
104   bool check_cancellation_or_degen(ShenandoahGC::ShenandoahDegenPoint point);
105   void resume_concurrent_old_cycle(ShenandoahGeneration* generation, GCCause::Cause cause);
106   void service_concurrent_cycle(ShenandoahGeneration* generation, GCCause::Cause cause, bool reset_old_bitmap_specially);
107   void service_stw_full_cycle(GCCause::Cause cause);
108 
109   // Return true if degenerated cycle finishes normally.  Return false if the degenerated cycle transformed itself
110   // into a full GC.
111   bool service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahGC::ShenandoahDegenPoint point);
112   void service_uncommit(double shrink_before, size_t shrink_until);
113 
114   bool try_set_alloc_failure_gc();
115   void notify_alloc_failure_waiters();
116   bool is_alloc_failure_gc();
117 
118   void reset_gc_id();
119   void update_gc_id();

120 
121   void notify_gc_waiters();
122 
123   // Handle GC request.
124   // Blocks until GC is over.
125   void handle_requested_gc(GCCause::Cause cause);
126 
127   bool is_explicit_gc(GCCause::Cause cause) const;
128   bool is_implicit_gc(GCCause::Cause cause) const;
129 
130   bool preempt_old_marking(GenerationMode generation);
131 
132   bool check_soft_max_changed() const;
133 
134 public:
135   // Constructor
136   ShenandoahControlThread();
137   ~ShenandoahControlThread();
138 
139   // Handle allocation failure from normal allocation.
140   // Blocks until memory is available.
141   void handle_alloc_failure(ShenandoahAllocRequest& req);
142 
143   // Handle allocation failure from evacuation path.
144   // Optionally blocks while collector is handling the failure.
145   void handle_alloc_failure_evac(size_t words);
146 
147   void request_gc(GCCause::Cause cause);
148   bool request_concurrent_gc(GenerationMode generation);
149 
150   void handle_counters_update();
151   void handle_force_counters_update();
152   void set_forced_counters_update(bool value);
153 
154   void notify_heap_changed();
155 
156   void pacing_notify_alloc(size_t words);
157 
158   void start();
159   void prepare_for_graceful_shutdown();
160   bool in_graceful_shutdown();
161 
162   const char* name() const { return "ShenandoahControlThread";}
163 
164   // Printing
165   void print_on(outputStream* st) const;
166   void print() const;
167 
168   void service_concurrent_normal_cycle(const ShenandoahHeap* heap,
169                                        const GenerationMode generation,
170                                        GCCause::Cause cause);
171 
172   void service_concurrent_old_cycle(const ShenandoahHeap* heap,
173                                     GCCause::Cause &cause);
174 
175   void set_gc_mode(GCMode new_mode);
176   GCMode gc_mode() {
177     return _mode;
178   }
179 
180  private:
181   static const char* gc_mode_name(GCMode mode);
182   void notify_control_thread();
183 };
184 
185 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCONTROLTHREAD_HPP
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