Commit | Line | Data |
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287a512f | 1 | /* |
ab5be9fa MJ |
2 | * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
3 | * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
287a512f | 4 | * |
ab5be9fa | 5 | * SPDX-License-Identifier: LGPL-2.1-only |
287a512f JG |
6 | * |
7 | * This code is originally adapted from userspace-rcu's urcu-wait.h | |
8 | */ | |
9 | ||
10 | #ifndef LTTNG_WAITER_H | |
11 | #define LTTNG_WAITER_H | |
12 | ||
13 | #define _LGPL_SOURCE | |
14 | ||
28f23191 JG |
15 | #include "macros.hpp" |
16 | ||
ac879184 | 17 | #include <functional> |
287a512f JG |
18 | #include <stdint.h> |
19 | #include <urcu/wfstack.h> | |
287a512f | 20 | |
32670d71 JG |
21 | namespace lttng { |
22 | namespace synchro { | |
23 | class waiter; | |
24 | class wait_queue; | |
25 | ||
eaa3b7be | 26 | class waker final { |
32670d71 JG |
27 | friend waiter; |
28 | ||
29 | public: | |
eaa3b7be JG |
30 | waker(const waker&) noexcept = default; |
31 | waker(waker&&) noexcept = default; | |
32 | waker& operator=(const waker& other) noexcept = default; | |
33 | waker& operator=(waker&& other) noexcept = default; | |
32670d71 JG |
34 | |
35 | void wake(); | |
36 | ||
37 | ~waker() = default; | |
287a512f | 38 | |
32670d71 | 39 | private: |
eaa3b7be | 40 | explicit waker(int32_t& state) noexcept : _state{ state } |
32670d71 JG |
41 | { |
42 | } | |
43 | ||
ac879184 | 44 | std::reference_wrapper<int32_t> _state; |
f40b76ae JG |
45 | }; |
46 | ||
32670d71 JG |
47 | class waiter final { |
48 | friend wait_queue; | |
287a512f | 49 | |
32670d71 JG |
50 | public: |
51 | waiter(); | |
287a512f | 52 | |
32670d71 JG |
53 | /* Deactivate copy and assignment. */ |
54 | waiter(const waiter&) = delete; | |
55 | waiter(waiter&&) = delete; | |
56 | waiter& operator=(const waiter&) = delete; | |
57 | waiter& operator=(waiter&&) = delete; | |
58 | ~waiter() = default; | |
f40b76ae | 59 | |
32670d71 JG |
60 | void arm() noexcept; |
61 | void wait(); | |
f40b76ae | 62 | |
32670d71 | 63 | waker get_waker(); |
f40b76ae | 64 | |
32670d71 JG |
65 | private: |
66 | cds_wfs_node _wait_queue_node; | |
67 | int32_t _state; | |
68 | }; | |
69 | ||
70 | class wait_queue final { | |
71 | public: | |
72 | wait_queue(); | |
73 | ||
74 | /* Deactivate copy and assignment. */ | |
75 | wait_queue(const wait_queue&) = delete; | |
76 | wait_queue(wait_queue&&) = delete; | |
77 | wait_queue& operator=(const wait_queue&) = delete; | |
78 | wait_queue& operator=(wait_queue&&) = delete; | |
79 | ~wait_queue() = default; | |
80 | ||
81 | /* | |
82 | * Atomically add a waiter to a wait queue. | |
83 | * A full memory barrier is issued before being added to the wait queue. | |
84 | */ | |
85 | void add(waiter& waiter) noexcept; | |
86 | /* | |
87 | * Wake every waiter present in the wait queue and remove them from | |
88 | * the queue. | |
89 | */ | |
90 | void wake_all(); | |
91 | ||
92 | private: | |
93 | cds_wfs_stack _stack; | |
94 | }; | |
95 | } /* namespace synchro */ | |
96 | } /* namespace lttng */ | |
287a512f JG |
97 | |
98 | #endif /* LTTNG_WAITER_H */ |