Generalize the interface of page space controller.

runtime/vm/pages.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PAGES_H_
 #define VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
+#include "vm/spaces.h"
 #include "vm/virtual_memory.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, collect_code);
 DECLARE_FLAG(bool, log_code_drop);
 DECLARE_FLAG(bool, always_drop_code);
 
 // Forward declarations.
 class Heap;
@@ skipping 89 matching lines @@
 // and if the relative GC time is below a given threshold,
 // then the heap is not grown when the next GC decision is made.
 // PageSpaceController controls the heap size.
 class PageSpaceController {
  public:
   PageSpaceController(int heap_growth_ratio,
                       int heap_growth_rate,
                       int garbage_collection_time_ratio);
   ~PageSpaceController();
 
-  bool CanGrowPageSpace(intptr_t size_in_bytes);
+  // Returns whether growing to 'after' should trigger a GC.
+  // This method can be called before allocation (e.g., pretenuring) or after
+  // (e.g., promotion), as it does not change the state of the controller.
+  bool NeedsGarbageCollection(SpaceUsage after) const;
 
+  // Should be called after each collection to update the controller state.
   // A garbage collection is considered as successful if more than
   // heap_growth_ratio % of memory got deallocated by the garbage collector.
   // In this case garbage collection will be performed next time. Otherwise
   // the heap will grow.
-  void EvaluateGarbageCollection(intptr_t used_before_in_words,
-                                 intptr_t used_after_in_words,
+  void EvaluateGarbageCollection(SpaceUsage before,
+                                 SpaceUsage after,
                                  int64_t start, int64_t end);
 
   int64_t last_code_collection_in_us() { return last_code_collection_in_us_; }
   void set_last_code_collection_in_us(int64_t t) {
     last_code_collection_in_us_ = t;
   }
 
   void set_is_enabled(bool state) {
     is_enabled_ = state;
   }
   bool is_enabled() {
     return is_enabled_;
   }
 
  private:
   bool is_enabled_;
 
+  // Usage after last evaluated GC.
+  SpaceUsage last_usage_;
+
   // Heap growth control variable.
   intptr_t grow_heap_;
 
   // If the garbage collector was not able to free more than heap_growth_ratio_
   // memory, then the heap is grown. Otherwise garbage collection is performed.
   int heap_growth_ratio_;
 
   // The desired percent of heap in-use after a garbage collection.
   // Equivalent to \frac{100-heap_growth_ratio_}{100}.
   double desired_utilization_;
@@ skipping 25 matching lines @@
     kForceGrowth
   };
 
   PageSpace(Heap* heap, intptr_t max_capacity_in_words);
   ~PageSpace();
 
   uword TryAllocate(intptr_t size,
                     HeapPage::PageType type = HeapPage::kData,
                     GrowthPolicy growth_policy = kControlGrowth);
 
-  intptr_t UsedInWords() const { return used_in_words_; }
-  intptr_t CapacityInWords() const { return capacity_in_words_; }
+  bool NeedsGarbageCollection() const {
+    return page_space_controller_.NeedsGarbageCollection(usage_);
+  }
+
+  intptr_t UsedInWords() const { return usage_.used_in_words; }
+  intptr_t CapacityInWords() const { return usage_.capacity_in_words; }
   intptr_t ExternalInWords() const {
-    return external_in_words_;
+    return usage_.external_in_words;
   }
+  SpaceUsage GetCurrentUsage() const { return usage_; }
 
   bool Contains(uword addr) const;
   bool Contains(uword addr, HeapPage::PageType type) const;
   bool IsValidAddress(uword addr) const {
     return Contains(addr);
   }
 
   void VisitObjects(ObjectVisitor* visitor) const;
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
@@ skipping 60 matching lines @@
 
   HeapPage* AllocatePage(HeapPage::PageType type);
   void FreePage(HeapPage* page, HeapPage* previous_page);
   HeapPage* AllocateLargePage(intptr_t size, HeapPage::PageType type);
   void FreeLargePage(HeapPage* page, HeapPage* previous_page);
   void FreePages(HeapPage* pages);
 
   static intptr_t LargePageSizeInWordsFor(intptr_t size);
 
   bool CanIncreaseCapacityInWords(intptr_t increase_in_words) {
-    ASSERT(capacity_in_words_ <= max_capacity_in_words_);
-    return increase_in_words <= (max_capacity_in_words_ - capacity_in_words_);
+    ASSERT(CapacityInWords() <= max_capacity_in_words_);
+    return increase_in_words <= (max_capacity_in_words_ - CapacityInWords());
   }
 
   FreeList freelist_[HeapPage::kNumPageTypes];
 
   Heap* heap_;
 
   HeapPage* pages_;
   HeapPage* pages_tail_;
   HeapPage* large_pages_;
 
   // Various sizes being tracked for this generation.
   intptr_t max_capacity_in_words_;
-  intptr_t capacity_in_words_;
-  intptr_t used_in_words_;
-  intptr_t external_in_words_;
+  SpaceUsage usage_;
 
   // Keep track whether a MarkSweep is currently running.
   bool sweeping_;
 
   PageSpaceController page_space_controller_;
 
   int64_t gc_time_micros_;
   intptr_t collections_;
 
   friend class PageSpaceController;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_