1 | /* Copyright 2020 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 | #include "tensorflow/core/util/incremental_barrier.h" |
17 | |
18 | #include <atomic> |
19 | #include <functional> |
20 | |
21 | #include "absl/functional/bind_front.h" |
22 | #include "tensorflow/core/platform/logging.h" |
23 | |
24 | namespace tensorflow { |
25 | |
26 | class InternalIncrementalBarrier { |
27 | public: |
28 | explicit InternalIncrementalBarrier(IncrementalBarrier::DoneCallback callback) |
29 | : left_(1), done_callback_(std::move(callback)) {} |
30 | |
31 | void operator()() { |
32 | DCHECK_GE(left_.load(std::memory_order_relaxed), 0); |
33 | |
34 | if (left_.fetch_sub(1, std::memory_order_acq_rel) - 1 == 0) { |
35 | IncrementalBarrier::DoneCallback done_callback = |
36 | std::move(done_callback_); |
37 | delete this; |
38 | done_callback(); |
39 | } |
40 | } |
41 | |
42 | IncrementalBarrier::BarrierCallback Inc() { |
43 | left_.fetch_add(1, std::memory_order_acq_rel); |
44 | |
45 | // std::bind_front is only available ever since C++20. |
46 | return absl::bind_front(&InternalIncrementalBarrier::operator(), this); |
47 | } |
48 | |
49 | private: |
50 | std::atomic<int> left_; |
51 | IncrementalBarrier::DoneCallback done_callback_; |
52 | }; |
53 | |
54 | IncrementalBarrier::IncrementalBarrier(DoneCallback done_callback) |
55 | : internal_barrier_( |
56 | new InternalIncrementalBarrier(std::move(done_callback))) {} |
57 | |
58 | IncrementalBarrier::~IncrementalBarrier() { (*internal_barrier_)(); } |
59 | |
60 | IncrementalBarrier::BarrierCallback IncrementalBarrier::Inc() { |
61 | return internal_barrier_->Inc(); |
62 | } |
63 | |
64 | } // namespace tensorflow |
65 |