1 /* Copyright 2015 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
16 // The temporary-memory-manager is a helper class for a Stream to keep track of
17 // temporary allocations. These allocations defer their deallocation to the next
18 // Stream::BlockHostUntilDone call for efficiency purposes (as deallocation
19 // itself generally forces synchronization to occur).
20
21 #ifndef TENSORFLOW_STREAM_EXECUTOR_TEMPORARY_MEMORY_MANAGER_H_
22 #define TENSORFLOW_STREAM_EXECUTOR_TEMPORARY_MEMORY_MANAGER_H_
23
24 #include <map>
25 #include <memory>
26
27 #include "tensorflow/stream_executor/device_memory.h"
28 #include "tensorflow/stream_executor/lib/status.h"
29 #include "tensorflow/stream_executor/lib/statusor.h"
30 #include "tensorflow/stream_executor/platform/mutex.h"
31 #include "tensorflow/stream_executor/platform/thread_annotations.h"
32 #include "tensorflow/stream_executor/temporary_device_memory.h"
33
34 namespace perftools {
35 namespace gputools {
36 namespace internal {
37
38 // Record used inside the TemporaryMemoryManager as metadata for a given device
39 // memory region.
40 struct TemporaryMemoryRecord {
41 // What "generation" this record was allocated in.
42 //
43 // Currently the generation counter is bumped for every allocation, but this
44 // could be made coarser if necessary.
45 uint64 allocation_generation;
46
47 // Notes whether the temporary memory has been marked as finalized, such that
48 // we can release the DeviceMemory associated with this record at
49 // synchronization time.
50 bool finalized;
51 };
52
53 // Manages temporary memories associated with a stream -- keeps records of
54 // outstanding temporaries and their state, and can deallocate them
55 // appropriately at points in the Stream lifecycle (e.g. BlockHostUntilDone,
56 // destruction).
57 class TemporaryMemoryManager {
58 public:
TemporaryMemoryManager(Stream * stream)59 explicit TemporaryMemoryManager(Stream* stream) : stream_(stream) {}
60
61 // Allocates a temporary array that is then managed by this object.
62 template <typename T>
63 port::StatusOr<std::unique_ptr<TemporaryDeviceMemory<T>>> AllocateArray(
64 uint64 element_count);
65
66 // Forces deallocation of all managed temporary memory regions.
67 //
68 // Called, for example, when the Stream owning this temporary memory manager
69 // is destroyed.
70 //
71 // Note: These calls to Deallocate will likely force synchronization.
72 void ForceDeallocateAll();
73
74 // Marks the given memory region as finalized.
75 //
76 // If must_exist is set, this will check-fail if the temporary memory record
77 // is not found.
78 void MarkFinalized(const DeviceMemoryBase& device_memory, uint64 generation,
79 bool must_exist);
80
81 // Deallocates temporary memories that have been finalized.
82 //
83 // Note: These calls to Deallocate will likely force synchronization, so it is
84 // meant to be called before a "BlockHostUntilDone" is about to be performed.
85 void DeallocateFinalizedTemporaries();
86
87 // Returns whether the provided device_memory is finalized.
88 //
89 // In the vacuous case where the device memory doesn't appear in the temporary
90 // memory records, it is either not a temporary at all, or has already been
91 // deallocated, and thus returns true.
92 bool IsFinalized(const DeviceMemoryBase& device_memory,
93 uint64 allocation_generation) const;
94
95 // Returns whether the manager has a live allocation record for the given
96 // device memory pointer with the given generation counter.
97 //
98 // Note: this is a polling call -- there is no guarantee that the region is
99 // still allocated once the call has completed.
100 bool HasAllocated(const DeviceMemoryBase& device_memory,
101 uint64 generation) const;
102
103 private:
104 // Allocates an array without type parameterization, so that the
105 // implementation can live in the source file. Without this base allocation
106 // method, we incur a circular dependency between the StreamExecutor
107 // definition and this class' definition.
108 port::StatusOr<std::unique_ptr<TemporaryDeviceMemoryBase>> AllocateArrayBase(
109 uint64 element_count, uint64 element_size);
110
111 // Mutex to guard temporary record state.
112 mutable mutex mutex_;
113
114 // Mapping from device memory to the current (live) temporary memory record.
115 //
116 // If a device memory is not in this mapping, it is not a temporary currently
117 // allocated and owned by this temporary memory manager.
118 std::map<DeviceMemoryBase, TemporaryMemoryRecord> records_ GUARDED_BY(mutex_);
119
120 // Allocation generation -- we bump this counter to distinguish temporary
121 // memory handles that have been deallocated and later reallocated at the same
122 // device memory address.
123 uint64 generation_ GUARDED_BY(mutex_);
124
125 // The stream (parent object) for this temporary memory manager -- allocations
126 // are performed through this stream handle.
127 Stream* stream_;
128
129 SE_DISALLOW_COPY_AND_ASSIGN(TemporaryMemoryManager);
130 };
131
132 ////////////
133 // Inlines
134
135 template <typename T>
136 port::StatusOr<std::unique_ptr<TemporaryDeviceMemory<T>>>
AllocateArray(uint64 element_count)137 TemporaryMemoryManager::AllocateArray(uint64 element_count) {
138 port::StatusOr<std::unique_ptr<TemporaryDeviceMemoryBase>> temporary_memory =
139 AllocateArrayBase(element_count, sizeof(T));
140 if (!temporary_memory.ok()) {
141 return temporary_memory.status();
142 }
143
144 return std::unique_ptr<TemporaryDeviceMemory<T>>(
145 reinterpret_cast<TemporaryDeviceMemory<T>*>(
146 temporary_memory.ConsumeValueOrDie().release()));
147 }
148
149 } // namespace internal
150 } // namespace gputools
151 } // namespace perftools
152
153 #endif // TENSORFLOW_STREAM_EXECUTOR_TEMPORARY_MEMORY_MANAGER_H_
154