src/hotspot/share/gc/g1/g1Policy.hpp

rev 60300 : 8249676: [REDO] G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs
Summary: Reapply JDK-8244603 after fixing JDK-8249192.
Reviewed-by:

@@ -58,11 +58,10 @@
 
   static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
   // Update the IHOP control with necessary statistics.
   void update_ihop_prediction(double mutator_time_s,
                               size_t mutator_alloc_bytes,
-                              size_t young_gen_size,
                               bool this_gc_was_young_only);
   void report_ihop_statistics();
 
   G1Predictions _predictor;
   G1Analytics* _analytics;

@@ -74,12 +73,12 @@
 
   double _full_collection_start_sec;
 
   jlong _collection_pause_end_millis;
 
+  uint _young_list_desired_length;
   uint _young_list_target_length;
-  uint _young_list_fixed_length;
 
   // The max number of regions we can extend the eden by while the GC
   // locker is active. This should be >= _young_list_target_length;
   uint _young_list_max_length;
 

@@ -168,10 +167,14 @@
     return _mmu_tracker->max_gc_time() * 1000.0;
   }
 
 private:
   G1CollectionSet* _collection_set;
+
+  bool next_gc_should_be_mixed(const char* true_action_str,
+                               const char* false_action_str) const;
+
   double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
   double other_time_ms(double pause_time_ms) const;
 
   double young_other_time_ms() const;
   double non_young_other_time_ms() const;

@@ -189,48 +192,42 @@
   // This set of variables tracks the collector efficiency, in order to
   // determine whether we should initiate a new marking.
   double _mark_remark_start_sec;
   double _mark_cleanup_start_sec;
 
-  // Updates the internal young list maximum and target lengths. Returns the
-  // unbounded young list target length. If no rs_length parameter is passed,
-  // predict the RS length using the prediction model, otherwise use the
-  // given rs_length as the prediction.
-  uint update_young_list_max_and_target_length();
-  uint update_young_list_max_and_target_length(size_t rs_length);
-
-  // Update the young list target length either by setting it to the
-  // desired fixed value or by calculating it using G1's pause
-  // prediction model.
-  // Returns the unbounded young list target length.
-  uint update_young_list_target_length(size_t rs_length);
-
-  // Calculate and return the minimum desired young list target
-  // length. This is the minimum desired young list length according
-  // to the user's inputs.
-  uint calculate_young_list_desired_min_length(uint base_min_length) const;
-
-  // Calculate and return the maximum desired young list target
-  // length. This is the maximum desired young list length according
-  // to the user's inputs.
-  uint calculate_young_list_desired_max_length() const;
-
-  // Calculate and return the maximum young list target length that
-  // can fit into the pause time goal. The parameters are: rs_length
-  // represent the prediction of how large the young RSet lengths will
-  // be, base_min_length is the already existing number of regions in
-  // the young list, min_length and max_length are the desired min and
-  // max young list length according to the user's inputs.
-  uint calculate_young_list_target_length(size_t rs_length,
-                                          uint base_min_length,
-                                          uint desired_min_length,
-                                          uint desired_max_length) const;
-
-  // Result of the bounded_young_list_target_length() method, containing both the
-  // bounded as well as the unbounded young list target lengths in this order.
-  typedef Pair<uint, uint, StackObj> YoungTargetLengths;
-  YoungTargetLengths young_list_target_lengths(size_t rs_length) const;
+  // Updates the internal young gen maximum and target and desired lengths.
+  // If no rs_length parameter is passed, predict the RS length using the
+  // prediction model, otherwise use the given rs_length as the prediction.
+  void update_young_length_bounds();
+  void update_young_length_bounds(size_t rs_length);
+
+  // Calculate and return the minimum desired eden length based on the MMU target.
+  uint calculate_desired_eden_length_by_mmu() const;
+
+  // Calculate and return the desired eden length that can fit into the pause time goal.
+  // The parameters are: rs_length represents the prediction of how large the
+  // young RSet lengths will be, min_eden_length and max_eden_length are the bounds
+  // (inclusive) within eden can grow.
+  uint calculate_desired_eden_length_by_pause(double base_time_ms,
+                                              uint min_eden_length,
+                                              uint max_eden_length) const;
+
+  // Calculates the desired eden length before mixed gc so that after adding the
+  // minimum amount of old gen regions from the collection set, the eden fits into
+  // the pause time goal.
+  uint calculate_desired_eden_length_before_mixed(double survivor_base_time_ms,
+                                                  uint min_eden_length,
+                                                  uint max_eden_length) const;
+
+  // Calculate desired young length based on current situation without taking actually
+  // available free regions into account.
+  uint calculate_young_desired_length(size_t rs_length) const;
+  // Limit the given desired young length to available free regions.
+  uint calculate_young_target_length(uint desired_young_length) const;
+  // The GCLocker might cause us to need more regions than the target. Calculate
+  // the maximum number of regions to use in that case.
+  uint calculate_young_max_length(uint target_young_length) const;
 
   void update_rs_length_prediction();
   void update_rs_length_prediction(size_t prediction);
 
   size_t predict_bytes_to_copy(HeapRegion* hr) const;

@@ -339,13 +336,10 @@
   void record_concurrent_mark_cleanup_start();
   void record_concurrent_mark_cleanup_end();
 
   void print_phases();
 
-  bool next_gc_should_be_mixed(const char* true_action_str,
-                               const char* false_action_str) const;
-
   // Calculate and return the number of initial and optional old gen regions from
   // the given collection set candidates and the remaining time.
   void calculate_old_collection_set_regions(G1CollectionSetCandidates* candidates,
                                             double time_remaining_ms,
                                             uint& num_initial_regions,

@@ -378,10 +372,11 @@
   // marking thread has completed its work during the previous cycle,
   // it will set in_concurrent_start_gc() to so that the pause does
   // the concurrent start work and start a marking cycle.
   void decide_on_conc_mark_initiation();
 
+  uint young_list_desired_length() const { return _young_list_desired_length; }
   size_t young_list_target_length() const { return _young_list_target_length; }
 
   bool should_allocate_mutator_region() const;
 
   bool can_expand_young_list() const;

@@ -438,12 +433,10 @@
     _survivors_age_table.merge(age_table);
   }
 
   void print_age_table();
 
-  void update_max_gc_locker_expansion();
-
   void update_survivors_policy();
 
   virtual bool force_upgrade_to_full() {
     return false;
   }