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 | ||
17 | #include <stdbool.h> | |
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 | ||
26 | class waker { | |
27 | friend waiter; | |
28 | ||
29 | public: | |
30 | waker(const waker&) = default; | |
31 | waker(waker&&) = default; | |
32 | waker& operator=(const waker& other) | |
33 | { | |
34 | _state = other._state; | |
35 | return *this; | |
36 | } | |
37 | waker& operator=(waker&& other) | |
38 | { | |
39 | _state = other._state; | |
40 | return *this; | |
41 | } | |
42 | ||
43 | void wake(); | |
44 | ||
45 | ~waker() = default; | |
287a512f | 46 | |
32670d71 JG |
47 | private: |
48 | waker(int32_t& state) : _state{ state } | |
49 | { | |
50 | } | |
51 | ||
52 | int32_t& _state; | |
f40b76ae JG |
53 | }; |
54 | ||
32670d71 JG |
55 | class waiter final { |
56 | friend wait_queue; | |
287a512f | 57 | |
32670d71 JG |
58 | public: |
59 | waiter(); | |
287a512f | 60 | |
32670d71 JG |
61 | /* Deactivate copy and assignment. */ |
62 | waiter(const waiter&) = delete; | |
63 | waiter(waiter&&) = delete; | |
64 | waiter& operator=(const waiter&) = delete; | |
65 | waiter& operator=(waiter&&) = delete; | |
66 | ~waiter() = default; | |
f40b76ae | 67 | |
32670d71 JG |
68 | void arm() noexcept; |
69 | void wait(); | |
f40b76ae | 70 | |
32670d71 | 71 | waker get_waker(); |
f40b76ae | 72 | |
32670d71 JG |
73 | private: |
74 | cds_wfs_node _wait_queue_node; | |
75 | int32_t _state; | |
76 | }; | |
77 | ||
78 | class wait_queue final { | |
79 | public: | |
80 | wait_queue(); | |
81 | ||
82 | /* Deactivate copy and assignment. */ | |
83 | wait_queue(const wait_queue&) = delete; | |
84 | wait_queue(wait_queue&&) = delete; | |
85 | wait_queue& operator=(const wait_queue&) = delete; | |
86 | wait_queue& operator=(wait_queue&&) = delete; | |
87 | ~wait_queue() = default; | |
88 | ||
89 | /* | |
90 | * Atomically add a waiter to a wait queue. | |
91 | * A full memory barrier is issued before being added to the wait queue. | |
92 | */ | |
93 | void add(waiter& waiter) noexcept; | |
94 | /* | |
95 | * Wake every waiter present in the wait queue and remove them from | |
96 | * the queue. | |
97 | */ | |
98 | void wake_all(); | |
99 | ||
100 | private: | |
101 | cds_wfs_stack _stack; | |
102 | }; | |
103 | } /* namespace synchro */ | |
104 | } /* namespace lttng */ | |
287a512f JG |
105 | |
106 | #endif /* LTTNG_WAITER_H */ |