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1 | // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- |
2 | // vim: ts=8 sw=2 smarttab | |
3 | /* | |
4 | * Ceph - scalable distributed file system | |
5 | * | |
6 | * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net> | |
7 | * | |
8 | * This is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License version 2.1, as published by the Free Software | |
11 | * Foundation. See file COPYING. | |
12 | * | |
13 | */ | |
14 | ||
15 | #ifndef CEPH_COMMON_MUTEX_DEBUG_H | |
16 | #define CEPH_COMMON_MUTEX_DEBUG_H | |
17 | ||
18 | #include <system_error> | |
19 | #include <thread> | |
20 | ||
21 | #include <pthread.h> | |
22 | ||
11fdf7f2 | 23 | #include "include/ceph_assert.h" |
7c673cae FG |
24 | |
25 | #include "ceph_time.h" | |
26 | #include "likely.h" | |
27 | #include "lockdep.h" | |
28 | ||
29 | class CephContext; | |
30 | class PerfCounters; | |
31 | ||
32 | namespace ceph { | |
33 | namespace mutex_debug_detail { | |
11fdf7f2 TL |
34 | |
35 | class mutex_debugging_base | |
36 | { | |
7c673cae FG |
37 | protected: |
38 | std::string name; | |
39 | int id; | |
40 | bool backtrace; // gather backtrace on lock acquisition | |
41 | ||
42 | int nlock; | |
43 | std::thread::id locked_by; | |
11fdf7f2 | 44 | |
7c673cae FG |
45 | |
46 | void _register(); | |
11fdf7f2 | 47 | void _will_lock(bool recursive=false); // about to lock |
7c673cae | 48 | void _locked(); // just locked |
11fdf7f2 | 49 | void _will_unlock(); // about to unlock |
7c673cae | 50 | |
11fdf7f2 TL |
51 | mutex_debugging_base(const std::string &n, bool bt = false); |
52 | mutex_debugging_base(const char *n, bool bt = false); | |
7c673cae FG |
53 | ~mutex_debugging_base(); |
54 | ||
7c673cae FG |
55 | public: |
56 | bool is_locked() const { | |
57 | return (nlock > 0); | |
58 | } | |
59 | bool is_locked_by_me() const { | |
60 | return nlock > 0 && locked_by == std::this_thread::get_id(); | |
61 | } | |
62 | operator bool() const { | |
63 | return nlock > 0 && locked_by == std::this_thread::get_id(); | |
64 | } | |
65 | }; | |
66 | ||
7c673cae FG |
67 | // Since this is a /debugging/ mutex just define it in terms of the |
68 | // pthread error check mutex. | |
69 | template<bool Recursive> | |
11fdf7f2 TL |
70 | class mutex_debug_impl : public mutex_debugging_base |
71 | { | |
7c673cae FG |
72 | private: |
73 | pthread_mutex_t m; | |
7c673cae | 74 | |
11fdf7f2 | 75 | void _init() { |
7c673cae FG |
76 | pthread_mutexattr_t a; |
77 | pthread_mutexattr_init(&a); | |
78 | int r; | |
79 | if (recursive) | |
80 | r = pthread_mutexattr_settype(&a, PTHREAD_MUTEX_RECURSIVE); | |
81 | else | |
82 | r = pthread_mutexattr_settype(&a, PTHREAD_MUTEX_ERRORCHECK); | |
11fdf7f2 | 83 | ceph_assert(r == 0); |
7c673cae | 84 | r = pthread_mutex_init(&m, &a); |
11fdf7f2 TL |
85 | ceph_assert(r == 0); |
86 | } | |
87 | ||
88 | bool enable_lockdep(bool no_lockdep) const { | |
89 | if (recursive) { | |
90 | return false; | |
91 | } else if (no_lockdep) { | |
92 | return false; | |
93 | } else { | |
94 | return g_lockdep; | |
95 | } | |
96 | } | |
97 | ||
98 | public: | |
99 | static constexpr bool recursive = Recursive; | |
100 | ||
101 | // Mutex concept is DefaultConstructible | |
102 | mutex_debug_impl(const std::string &n, bool bt = false) | |
103 | : mutex_debugging_base(n, bt) { | |
104 | _init(); | |
105 | } | |
106 | mutex_debug_impl(const char *n, bool bt = false) | |
107 | : mutex_debugging_base(n, bt) { | |
108 | _init(); | |
7c673cae | 109 | } |
11fdf7f2 | 110 | |
7c673cae FG |
111 | // Mutex is Destructible |
112 | ~mutex_debug_impl() { | |
113 | int r = pthread_mutex_destroy(&m); | |
11fdf7f2 | 114 | ceph_assert(r == 0); |
7c673cae FG |
115 | } |
116 | ||
117 | // Mutex concept is non-Copyable | |
118 | mutex_debug_impl(const mutex_debug_impl&) = delete; | |
119 | mutex_debug_impl& operator =(const mutex_debug_impl&) = delete; | |
120 | ||
121 | // Mutex concept is non-Movable | |
122 | mutex_debug_impl(mutex_debug_impl&&) = delete; | |
123 | mutex_debug_impl& operator =(mutex_debug_impl&&) = delete; | |
124 | ||
125 | void lock_impl() { | |
126 | int r = pthread_mutex_lock(&m); | |
127 | // Allowed error codes for Mutex concept | |
128 | if (unlikely(r == EPERM || | |
129 | r == EDEADLK || | |
130 | r == EBUSY)) { | |
131 | throw std::system_error(r, std::generic_category()); | |
132 | } | |
11fdf7f2 | 133 | ceph_assert(r == 0); |
7c673cae FG |
134 | } |
135 | ||
136 | void unlock_impl() noexcept { | |
137 | int r = pthread_mutex_unlock(&m); | |
11fdf7f2 | 138 | ceph_assert(r == 0); |
7c673cae FG |
139 | } |
140 | ||
141 | bool try_lock_impl() { | |
142 | int r = pthread_mutex_trylock(&m); | |
143 | switch (r) { | |
144 | case 0: | |
145 | return true; | |
146 | case EBUSY: | |
147 | return false; | |
148 | default: | |
149 | throw std::system_error(r, std::generic_category()); | |
150 | } | |
151 | } | |
11fdf7f2 TL |
152 | pthread_mutex_t* native_handle() { |
153 | return &m; | |
154 | } | |
155 | ||
156 | void _post_lock() { | |
157 | if (!recursive) | |
158 | ceph_assert(nlock == 0); | |
159 | locked_by = std::this_thread::get_id(); | |
160 | nlock++; | |
161 | } | |
162 | ||
163 | void _pre_unlock() { | |
164 | ceph_assert(nlock > 0); | |
165 | --nlock; | |
166 | ceph_assert(locked_by == std::this_thread::get_id()); | |
167 | if (!recursive) | |
168 | ceph_assert(nlock == 0); | |
169 | if (nlock == 0) | |
170 | locked_by = std::thread::id(); | |
171 | } | |
172 | ||
173 | bool try_lock(bool no_lockdep = false) { | |
174 | bool locked = try_lock_impl(); | |
175 | if (locked) { | |
176 | if (enable_lockdep(no_lockdep)) | |
177 | _locked(); | |
178 | _post_lock(); | |
179 | } | |
180 | return locked; | |
181 | } | |
182 | ||
183 | void lock(bool no_lockdep = false) { | |
184 | if (enable_lockdep(no_lockdep)) | |
185 | _will_lock(recursive); | |
186 | ||
187 | if (try_lock()) | |
188 | return; | |
189 | ||
190 | lock_impl(); | |
191 | if (enable_lockdep(no_lockdep)) | |
192 | _locked(); | |
193 | _post_lock(); | |
194 | } | |
195 | ||
196 | void unlock(bool no_lockdep = false) { | |
197 | _pre_unlock(); | |
198 | if (enable_lockdep(no_lockdep)) | |
199 | _will_unlock(); | |
200 | unlock_impl(); | |
201 | } | |
202 | ||
7c673cae | 203 | }; |
11fdf7f2 TL |
204 | |
205 | ||
7c673cae FG |
206 | } // namespace mutex_debug_detail |
207 | typedef mutex_debug_detail::mutex_debug_impl<false> mutex_debug; | |
208 | typedef mutex_debug_detail::mutex_debug_impl<true> mutex_recursive_debug; | |
209 | } // namespace ceph | |
210 | ||
211 | #endif |