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 | #ifndef TENSORFLOW_CORE_FRAMEWORK_OP_SEGMENT_H_ |
17 | #define TENSORFLOW_CORE_FRAMEWORK_OP_SEGMENT_H_ |
18 | |
19 | #include <string> |
20 | #include <unordered_map> |
21 | |
22 | #include "tensorflow/core/framework/op_kernel.h" |
23 | #include "tensorflow/core/lib/core/status.h" |
24 | #include "tensorflow/core/platform/macros.h" |
25 | #include "tensorflow/core/platform/mutex.h" |
26 | #include "tensorflow/core/platform/thread_annotations.h" |
27 | #include "tensorflow/core/platform/types.h" |
28 | |
29 | namespace tensorflow { |
30 | |
31 | // OpSegment keeps track of OpKernels registered for sessions running |
32 | // on a device. |
33 | // |
34 | // The implementation maintains a two-level map. The 1st level maps |
35 | // session handle to the map of registered OpKernels. The 2nd level |
36 | // map maps node names to instantiated OpKernel objects. |
37 | // |
38 | // Each 2-nd level map is reference-counted and the caller can call |
39 | // AddHold to obtain a reference on all kernels of a session and |
40 | // ensure these kernels are alive until a corresponding RemoveHold is |
41 | // called on the same session. |
42 | class OpSegment { |
43 | public: |
44 | OpSegment(); |
45 | ~OpSegment(); |
46 | |
47 | // A hold can be placed on a session, preventing all its kernels |
48 | // from being deleted. |
49 | void AddHold(const std::string& session_handle); |
50 | void RemoveHold(const std::string& session_handle); |
51 | |
52 | // If the kernel for "node_name" has been created in the |
53 | // "session_handle", returns the existing op kernel in "*kernel". |
54 | // Otherwise, creates the kernel by calling create_fn(), cache it, |
55 | // and returns it in "*kernel". If create_fn() fails, returns the |
56 | // error. |
57 | // |
58 | // OpSegment keeps the ownership of the returned "*kernel". |
59 | typedef std::function<Status(OpKernel**)> CreateKernelFn; |
60 | Status FindOrCreate(const std::string& session_handle, |
61 | const std::string& node_name, OpKernel** kernel, |
62 | CreateKernelFn create_fn); |
63 | |
64 | // Returns true if OpSegment should own the kernel. |
65 | static bool ShouldOwnKernel(FunctionLibraryRuntime* lib, |
66 | const std::string& node_op); |
67 | |
68 | private: |
69 | // op name -> OpKernel |
70 | typedef std::unordered_map<string, OpKernel*> KernelMap; |
71 | struct Item { |
72 | int num_holds = 1; // Num of holds put on the session. |
73 | KernelMap name_kernel; // op name -> kernel. |
74 | ~Item(); |
75 | }; |
76 | |
77 | // session handle -> item. |
78 | // Session handles are produced by strings::FpToString() |
79 | typedef std::unordered_map<string, Item*> SessionMap; |
80 | |
81 | mutable mutex mu_; |
82 | SessionMap sessions_ TF_GUARDED_BY(mu_); |
83 | |
84 | TF_DISALLOW_COPY_AND_ASSIGN(OpSegment); |
85 | }; |
86 | |
87 | } // end namespace tensorflow |
88 | |
89 | #endif // TENSORFLOW_CORE_FRAMEWORK_OP_SEGMENT_H_ |
90 | |