1 | /* Copyright 2018 The TensorFlow Authors. All Rights Reserved. |
2 | |
3 | Licensed under the Apache License, Version 2.0 (the "License"); |
4 | you may not use this file except in compliance with the License. |
5 | You may obtain a copy of the License at |
6 | |
7 | http://www.apache.org/licenses/LICENSE-2.0 |
8 | |
9 | Unless required by applicable law or agreed to in writing, software |
10 | distributed under the License is distributed on an "AS IS" BASIS, |
11 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | See the License for the specific language governing permissions and |
13 | limitations under the License. |
14 | ==============================================================================*/ |
15 | #ifndef TENSORFLOW_CORE_COMMON_RUNTIME_SCOPED_ALLOCATOR_H_ |
16 | #define TENSORFLOW_CORE_COMMON_RUNTIME_SCOPED_ALLOCATOR_H_ |
17 | |
18 | #include "tensorflow/core/framework/allocator.h" |
19 | #include "tensorflow/core/framework/tensor.h" |
20 | #include "tensorflow/core/lib/core/refcount.h" |
21 | #include "tensorflow/core/platform/mutex.h" |
22 | |
23 | namespace tensorflow { |
24 | class ScopedAllocatorContainer; |
25 | class ScopedAllocatorInstance; |
26 | |
27 | // Manages a single backing tensor and a collection of aliases. |
28 | class ScopedAllocator { |
29 | public: |
30 | static constexpr int32_t kInvalidId = 0; |
31 | static constexpr size_t kMaxAlignment = 64; |
32 | |
33 | // A subrange of the TensorBuffer associated with this object that |
34 | // will be the backing memory for one aliased tensor. |
35 | struct Field { |
36 | int32 scope_id; |
37 | size_t offset; |
38 | size_t bytes_requested; |
39 | size_t bytes_allocated; |
40 | }; |
41 | // Field index that refers to backing tensor, not any aliased field. |
42 | static constexpr int32_t kBackingIndex = -1; |
43 | |
44 | // backing_tensor is expected to be newly allocated by a ScopedAllocatorOp |
45 | // instance. It must be large enough to back all of the specified |
46 | // (offset, byte) ranges of the fields. |
47 | ScopedAllocator(const Tensor& backing_tensor, int32_t scope_id, |
48 | const std::string& name, const gtl::ArraySlice<Field> fields, |
49 | int32_t expected_call_count, |
50 | ScopedAllocatorContainer* container); |
51 | |
52 | // Automatically deletes when last use expires, or when |
53 | // ScopedAllocatorContainer decides to delete. |
54 | ~ScopedAllocator() TF_LOCKS_EXCLUDED(mu_); |
55 | |
56 | // For debugging: returns true iff p is a pointer that could have |
57 | // been returned by AllocateRaw. |
58 | bool VerifyPointer(const void* p); |
59 | bool VerifyTensor(const Tensor* t); |
60 | |
61 | const Tensor& tensor() const { return backing_tensor_; } |
62 | |
63 | const std::string& name() const { return name_; } |
64 | |
65 | private: |
66 | friend class ScopedAllocatorInstance; |
67 | // Only ScopedAllocatorInstances can call AllocateRaw and DeallocateRaw on a |
68 | // ScopedAllocator |
69 | void* AllocateRaw(int32_t field_index, size_t num_bytes) |
70 | TF_LOCKS_EXCLUDED(mu_); |
71 | void DeallocateRaw(void* p) TF_LOCKS_EXCLUDED(mu_); |
72 | Tensor backing_tensor_; |
73 | TensorBuffer* tbuf_; |
74 | int32 id_; |
75 | std::string name_; |
76 | ScopedAllocatorContainer* container_; |
77 | std::vector<Field> fields_; |
78 | mutex mu_; |
79 | int32 expected_call_count_ TF_GUARDED_BY(mu_); |
80 | int32 live_alloc_count_ TF_GUARDED_BY(mu_); |
81 | }; |
82 | |
83 | // An Allocator that will return a pointer into the backing buffer of |
84 | // a previously allocated tensor, allowing creation of an alias |
85 | // tensor. There is a one-to-one mapping between the fields of a |
86 | // ScopedAllocator and ScopedAllocatorInstances. There is also a one-to-one |
87 | // mapping between scope_ids and ScopedAllocatorInstances. It should be |
88 | // discarded immediately after a single use. |
89 | class ScopedAllocatorInstance : public Allocator { |
90 | public: |
91 | explicit ScopedAllocatorInstance(ScopedAllocator* sa, int32_t field_index); |
92 | |
93 | private: |
94 | ~ScopedAllocatorInstance() override { |
95 | VLOG(1) << "~ScopedAllocatorInstance " << this; |
96 | } |
97 | |
98 | public: |
99 | // When a ScopedAllocatorContainer "Drops" a scope_id, it calls DropFromTable |
100 | // on the underlying ScopedAllocatorInstance. If this instance has already |
101 | // deallocated the tensor slice, we can safely delete this. |
102 | void DropFromTable() TF_LOCKS_EXCLUDED(mu_); |
103 | void* AllocateRaw(size_t alignment, size_t num_bytes) |
104 | TF_LOCKS_EXCLUDED(mu_) override; |
105 | void* AllocateRaw(size_t alignment, size_t num_bytes, |
106 | const AllocationAttributes& allocator_attr) override { |
107 | return AllocateRaw(alignment, num_bytes); |
108 | } |
109 | void DeallocateRaw(void* p) TF_LOCKS_EXCLUDED(mu_) override; |
110 | bool TracksAllocationSizes() const override { return false; } |
111 | size_t RequestedSize(const void* ptr) const override { return 0; } |
112 | size_t AllocatedSize(const void* ptr) const override { return 0; } |
113 | int64_t AllocationId(const void* ptr) const override { return 0; } |
114 | size_t AllocatedSizeSlow(const void* ptr) const override { return 0; } |
115 | std::string Name() override; |
116 | |
117 | private: |
118 | mutex mu_; |
119 | ScopedAllocator* scoped_allocator_; |
120 | int32 field_index_; |
121 | bool allocated_ TF_GUARDED_BY(mu_); |
122 | bool deallocated_ TF_GUARDED_BY(mu_); |
123 | bool in_table_ TF_GUARDED_BY(mu_); |
124 | }; |
125 | |
126 | } // namespace tensorflow |
127 | #endif // TENSORFLOW_CORE_COMMON_RUNTIME_SCOPED_ALLOCATOR_H_ |
128 | |