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

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@@ -1,7 +1,8 @@
  /*
   * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
+  * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.

@@ -23,19 +24,21 @@
   */
  
  #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHALLOCREQUEST_HPP
  #define SHARE_GC_SHENANDOAH_SHENANDOAHALLOCREQUEST_HPP
  
+ #include "gc/shenandoah/shenandoahAffiliation.hpp"
  #include "memory/allocation.hpp"
  
  class ShenandoahAllocRequest : StackObj {
  public:
    enum Type {
      _alloc_shared,      // Allocate common, outside of TLAB
-     _alloc_shared_gc,   // Allocate common, outside of GCLAB
+     _alloc_shared_gc,   // Allocate common, outside of GCLAB/PLAB
      _alloc_tlab,        // Allocate TLAB
      _alloc_gclab,       // Allocate GCLAB
+     _alloc_plab,        // Allocate PLAB
      _ALLOC_LIMIT
    };
  
    static const char* alloc_type_to_string(Type type) {
      switch (type) {

@@ -45,68 +48,99 @@
          return "Shared GC";
        case _alloc_tlab:
          return "TLAB";
        case _alloc_gclab:
          return "GCLAB";
+       case _alloc_plab:
+         return "PLAB";
        default:
          ShouldNotReachHere();
          return "";
      }
    }
  
  private:
+   // When ShenandoahElasticTLAB is enabled, the request cannot be made smaller than _min_size.
    size_t _min_size;
+ 
+   // The size of the request in words.
    size_t _requested_size;
+ 
+   // The allocation may be increased for padding or decreased to fit in the remaining space of a region.
    size_t _actual_size;
+ 
+   // For a humongous object, the _waste is the amount of free memory in the last region.
+   // For other requests, the _waste will be non-zero if the request enountered one or more regions
+   // with less memory than _min_size. This waste does not contribute to the used memory for
+   // the heap, but it does contribute to the allocation rate for heuristics.
+   size_t _waste;
+ 
+   // This is the type of the request.
    Type _alloc_type;
+ 
+   // This is the generation which the request is targeting.
+   ShenandoahAffiliation const _affiliation;
+ 
+   // True if this request is trying to copy any object from young to old (promote).
+   bool _is_promotion;
+ 
  #ifdef ASSERT
+   // Check that this is set before being read.
    bool _actual_size_set;
  #endif
  
-   ShenandoahAllocRequest(size_t _min_size, size_t _requested_size, Type _alloc_type) :
+   ShenandoahAllocRequest(size_t _min_size, size_t _requested_size, Type _alloc_type, ShenandoahAffiliation affiliation, bool is_promotion = false) :
            _min_size(_min_size), _requested_size(_requested_size),
-           _actual_size(0), _alloc_type(_alloc_type)
+           _actual_size(0), _waste(0), _alloc_type(_alloc_type), _affiliation(affiliation), _is_promotion(is_promotion)
  #ifdef ASSERT
            , _actual_size_set(false)
  #endif
    {}
  
  public:
    static inline ShenandoahAllocRequest for_tlab(size_t min_size, size_t requested_size) {
-     return ShenandoahAllocRequest(min_size, requested_size, _alloc_tlab);
+     return ShenandoahAllocRequest(min_size, requested_size, _alloc_tlab, ShenandoahAffiliation::YOUNG_GENERATION);
    }
  
    static inline ShenandoahAllocRequest for_gclab(size_t min_size, size_t requested_size) {
-     return ShenandoahAllocRequest(min_size, requested_size, _alloc_gclab);
+     return ShenandoahAllocRequest(min_size, requested_size, _alloc_gclab, ShenandoahAffiliation::YOUNG_GENERATION);
+   }
+ 
+   static inline ShenandoahAllocRequest for_plab(size_t min_size, size_t requested_size) {
+     return ShenandoahAllocRequest(min_size, requested_size, _alloc_plab, ShenandoahAffiliation::OLD_GENERATION);
    }
  
-   static inline ShenandoahAllocRequest for_shared_gc(size_t requested_size) {
-     return ShenandoahAllocRequest(0, requested_size, _alloc_shared_gc);
+   static inline ShenandoahAllocRequest for_shared_gc(size_t requested_size, ShenandoahAffiliation affiliation, bool is_promotion = false) {
+     if (is_promotion) {
+       assert(affiliation == ShenandoahAffiliation::OLD_GENERATION, "Should only promote to old generation");
+       return ShenandoahAllocRequest(0, requested_size, _alloc_shared_gc, affiliation, true);
+     }
+     return ShenandoahAllocRequest(0, requested_size, _alloc_shared_gc, affiliation);
    }
  
    static inline ShenandoahAllocRequest for_shared(size_t requested_size) {
-     return ShenandoahAllocRequest(0, requested_size, _alloc_shared);
+     return ShenandoahAllocRequest(0, requested_size, _alloc_shared, ShenandoahAffiliation::YOUNG_GENERATION);
    }
  
-   inline size_t size() {
+   inline size_t size() const {
      return _requested_size;
    }
  
-   inline Type type() {
+   inline Type type() const {
      return _alloc_type;
    }
  
-   inline const char* type_string() {
+   inline const char* type_string() const {
      return alloc_type_to_string(_alloc_type);
    }
  
-   inline size_t min_size() {
+   inline size_t min_size() const {
      assert (is_lab_alloc(), "Only access for LAB allocs");
      return _min_size;
    }
  
-   inline size_t actual_size() {
+   inline size_t actual_size() const {
      assert (_actual_size_set, "Should be set");
      return _actual_size;
    }
  
    inline void set_actual_size(size_t v) {

@@ -115,49 +149,80 @@
      _actual_size_set = true;
  #endif
      _actual_size = v;
    }
  
-   inline bool is_mutator_alloc() {
+   inline size_t waste() const {
+     return _waste;
+   }
+ 
+   inline void set_waste(size_t v) {
+     _waste = v;
+   }
+ 
+   inline bool is_mutator_alloc() const {
      switch (_alloc_type) {
        case _alloc_tlab:
        case _alloc_shared:
          return true;
        case _alloc_gclab:
+       case _alloc_plab:
        case _alloc_shared_gc:
          return false;
        default:
          ShouldNotReachHere();
          return false;
      }
    }
  
-   inline bool is_gc_alloc() {
+   inline bool is_gc_alloc() const {
      switch (_alloc_type) {
        case _alloc_tlab:
        case _alloc_shared:
          return false;
        case _alloc_gclab:
+       case _alloc_plab:
        case _alloc_shared_gc:
          return true;
        default:
          ShouldNotReachHere();
          return false;
      }
    }
  
-   inline bool is_lab_alloc() {
+   inline bool is_lab_alloc() const {
      switch (_alloc_type) {
        case _alloc_tlab:
        case _alloc_gclab:
+       case _alloc_plab:
          return true;
        case _alloc_shared:
        case _alloc_shared_gc:
          return false;
        default:
          ShouldNotReachHere();
          return false;
      }
    }
+ 
+   bool is_old() const {
+     return _affiliation == OLD_GENERATION;
+   }
+ 
+   bool is_young() const {
+     return _affiliation == YOUNG_GENERATION;
+   }
+ 
+   ShenandoahAffiliation affiliation() const {
+     return _affiliation;
+   }
+ 
+   const char* affiliation_name() const {
+     return shenandoah_affiliation_name(_affiliation);
+   }
+ 
+   bool is_promotion() const {
+     return _is_promotion;
+   }
  };
  
  #endif // SHARE_GC_SHENANDOAH_SHENANDOAHALLOCREQUEST_HPP
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