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1 // Copyright 2016 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_ZONE_ACCOUNTING_ALLOCATOR_H_
6 #define V8_ZONE_ACCOUNTING_ALLOCATOR_H_
7 
8 #include "include/v8-platform.h"
9 #include "src/base/atomic-utils.h"
10 #include "src/base/atomicops.h"
11 #include "src/base/macros.h"
12 #include "src/base/platform/mutex.h"
13 #include "src/base/platform/semaphore.h"
14 #include "src/base/platform/time.h"
15 #include "src/zone/zone-segment.h"
16 #include "testing/gtest/include/gtest/gtest_prod.h"
17 
18 namespace v8 {
19 namespace internal {
20 
21 class V8_EXPORT_PRIVATE AccountingAllocator {
22  public:
23   static const size_t kMaxPoolSizeLowMemoryDevice = 8ul * KB;
24   static const size_t kMaxPoolSizeMediumMemoryDevice = 8ul * KB;
25   static const size_t kMaxPoolSizeHighMemoryDevice = 8ul * KB;
26   static const size_t kMaxPoolSizeHugeMemoryDevice = 8ul * KB;
27 
28   AccountingAllocator();
29   virtual ~AccountingAllocator();
30 
31   // Gets an empty segment from the pool or creates a new one.
32   virtual Segment* GetSegment(size_t bytes);
33   // Return unneeded segments to either insert them into the pool or release
34   // them if the pool is already full or memory pressure is high.
35   virtual void ReturnSegment(Segment* memory);
36 
37   size_t GetCurrentMemoryUsage() const;
38   size_t GetMaxMemoryUsage() const;
39 
40   size_t GetCurrentPoolSize() const;
41 
42   void MemoryPressureNotification(MemoryPressureLevel level);
43   // Configures the zone segment pool size limits so the pool does not
44   // grow bigger than max_pool_size.
45   // TODO(heimbuef): Do not accept segments to pool that are larger than
46   // their size class requires. Sometimes the zones generate weird segments.
47   void ConfigureSegmentPool(const size_t max_pool_size);
48 
ZoneCreation(const Zone * zone)49   virtual void ZoneCreation(const Zone* zone) {}
ZoneDestruction(const Zone * zone)50   virtual void ZoneDestruction(const Zone* zone) {}
51 
52  private:
53   FRIEND_TEST(Zone, SegmentPoolConstraints);
54 
55   static const size_t kMinSegmentSizePower = 13;
56   static const size_t kMaxSegmentSizePower = 18;
57 
58   STATIC_ASSERT(kMinSegmentSizePower <= kMaxSegmentSizePower);
59 
60   static const size_t kNumberBuckets =
61       1 + kMaxSegmentSizePower - kMinSegmentSizePower;
62 
63   // Allocates a new segment. Returns nullptr on failed allocation.
64   Segment* AllocateSegment(size_t bytes);
65   void FreeSegment(Segment* memory);
66 
67   // Returns a segment from the pool of at least the requested size.
68   Segment* GetSegmentFromPool(size_t requested_size);
69   // Trys to add a segment to the pool. Returns false if the pool is full.
70   bool AddSegmentToPool(Segment* segment);
71 
72   // Empties the pool and puts all its contents onto the garbage stack.
73   void ClearPool();
74 
75   Segment* unused_segments_heads_[kNumberBuckets];
76 
77   size_t unused_segments_sizes_[kNumberBuckets];
78   size_t unused_segments_max_sizes_[kNumberBuckets];
79 
80   base::Mutex unused_segments_mutex_;
81 
82   base::AtomicWord current_memory_usage_ = 0;
83   base::AtomicWord max_memory_usage_ = 0;
84   base::AtomicWord current_pool_size_ = 0;
85 
86   base::AtomicValue<MemoryPressureLevel> memory_pressure_level_;
87 
88   DISALLOW_COPY_AND_ASSIGN(AccountingAllocator);
89 };
90 
91 }  // namespace internal
92 }  // namespace v8
93 
94 #endif  // V8_ZONE_ACCOUNTING_ALLOCATOR_H_
95