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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_FINISHER_H | |
16 | #define CEPH_FINISHER_H | |
17 | ||
7c673cae FG |
18 | #include "common/Mutex.h" |
19 | #include "common/Cond.h" | |
7c673cae FG |
20 | #include "common/perf_counters.h" |
21 | ||
22 | class CephContext; | |
23 | ||
24 | /// Finisher queue length performance counter ID. | |
25 | enum { | |
26 | l_finisher_first = 997082, | |
27 | l_finisher_queue_len, | |
28 | l_finisher_complete_lat, | |
29 | l_finisher_last | |
30 | }; | |
31 | ||
32 | /** @brief Asynchronous cleanup class. | |
33 | * Finisher asynchronously completes Contexts, which are simple classes | |
34 | * representing callbacks, in a dedicated worker thread. Enqueuing | |
35 | * contexts to complete is thread-safe. | |
36 | */ | |
37 | class Finisher { | |
38 | CephContext *cct; | |
39 | Mutex finisher_lock; ///< Protects access to queues and finisher_running. | |
40 | Cond finisher_cond; ///< Signaled when there is something to process. | |
41 | Cond finisher_empty_cond; ///< Signaled when the finisher has nothing more to process. | |
42 | bool finisher_stop; ///< Set when the finisher should stop. | |
43 | bool finisher_running; ///< True when the finisher is currently executing contexts. | |
44 | bool finisher_empty_wait; ///< True mean someone wait finisher empty. | |
45 | /// Queue for contexts for which complete(0) will be called. | |
46 | /// NULLs in this queue indicate that an item from finisher_queue_rval | |
47 | /// should be completed in that place instead. | |
48 | vector<Context*> finisher_queue; | |
49 | ||
50 | string thread_name; | |
51 | ||
52 | /// Queue for contexts for which the complete function will be called | |
53 | /// with a parameter other than 0. | |
54 | list<pair<Context*,int> > finisher_queue_rval; | |
55 | ||
56 | /// Performance counter for the finisher's queue length. | |
57 | /// Only active for named finishers. | |
58 | PerfCounters *logger; | |
59 | ||
60 | void *finisher_thread_entry(); | |
61 | ||
62 | struct FinisherThread : public Thread { | |
63 | Finisher *fin; | |
64 | explicit FinisherThread(Finisher *f) : fin(f) {} | |
65 | void* entry() override { return (void*)fin->finisher_thread_entry(); } | |
66 | } finisher_thread; | |
67 | ||
68 | public: | |
69 | /// Add a context to complete, optionally specifying a parameter for the complete function. | |
70 | void queue(Context *c, int r = 0) { | |
71 | finisher_lock.Lock(); | |
72 | if (finisher_queue.empty()) { | |
73 | finisher_cond.Signal(); | |
74 | } | |
75 | if (r) { | |
76 | finisher_queue_rval.push_back(pair<Context*, int>(c, r)); | |
77 | finisher_queue.push_back(NULL); | |
78 | } else | |
79 | finisher_queue.push_back(c); | |
80 | if (logger) | |
81 | logger->inc(l_finisher_queue_len); | |
82 | finisher_lock.Unlock(); | |
83 | } | |
84 | void queue(vector<Context*>& ls) { | |
85 | finisher_lock.Lock(); | |
86 | if (finisher_queue.empty()) { | |
87 | finisher_cond.Signal(); | |
88 | } | |
89 | finisher_queue.insert(finisher_queue.end(), ls.begin(), ls.end()); | |
90 | if (logger) | |
91 | logger->inc(l_finisher_queue_len, ls.size()); | |
92 | finisher_lock.Unlock(); | |
93 | ls.clear(); | |
94 | } | |
95 | void queue(deque<Context*>& ls) { | |
96 | finisher_lock.Lock(); | |
97 | if (finisher_queue.empty()) { | |
98 | finisher_cond.Signal(); | |
99 | } | |
100 | finisher_queue.insert(finisher_queue.end(), ls.begin(), ls.end()); | |
101 | if (logger) | |
102 | logger->inc(l_finisher_queue_len, ls.size()); | |
103 | finisher_lock.Unlock(); | |
104 | ls.clear(); | |
105 | } | |
106 | void queue(list<Context*>& ls) { | |
107 | finisher_lock.Lock(); | |
108 | if (finisher_queue.empty()) { | |
109 | finisher_cond.Signal(); | |
110 | } | |
111 | finisher_queue.insert(finisher_queue.end(), ls.begin(), ls.end()); | |
112 | if (logger) | |
113 | logger->inc(l_finisher_queue_len, ls.size()); | |
114 | finisher_lock.Unlock(); | |
115 | ls.clear(); | |
116 | } | |
117 | ||
118 | /// Start the worker thread. | |
119 | void start(); | |
120 | ||
121 | /** @brief Stop the worker thread. | |
122 | * | |
123 | * Does not wait until all outstanding contexts are completed. | |
124 | * To ensure that everything finishes, you should first shut down | |
125 | * all sources that can add contexts to this finisher and call | |
126 | * wait_for_empty() before calling stop(). */ | |
127 | void stop(); | |
128 | ||
129 | /** @brief Blocks until the finisher has nothing left to process. | |
130 | * This function will also return when a concurrent call to stop() | |
131 | * finishes, but this class should never be used in this way. */ | |
132 | void wait_for_empty(); | |
133 | ||
134 | /// Construct an anonymous Finisher. | |
135 | /// Anonymous finishers do not log their queue length. | |
136 | explicit Finisher(CephContext *cct_) : | |
137 | cct(cct_), finisher_lock("Finisher::finisher_lock"), | |
138 | finisher_stop(false), finisher_running(false), finisher_empty_wait(false), | |
139 | thread_name("fn_anonymous"), logger(0), | |
140 | finisher_thread(this) {} | |
141 | ||
142 | /// Construct a named Finisher that logs its queue length. | |
143 | Finisher(CephContext *cct_, string name, string tn) : | |
144 | cct(cct_), finisher_lock("Finisher::" + name), | |
145 | finisher_stop(false), finisher_running(false), finisher_empty_wait(false), | |
146 | thread_name(tn), logger(0), | |
147 | finisher_thread(this) { | |
148 | PerfCountersBuilder b(cct, string("finisher-") + name, | |
149 | l_finisher_first, l_finisher_last); | |
150 | b.add_u64(l_finisher_queue_len, "queue_len"); | |
151 | b.add_time_avg(l_finisher_complete_lat, "complete_latency"); | |
152 | logger = b.create_perf_counters(); | |
153 | cct->get_perfcounters_collection()->add(logger); | |
154 | logger->set(l_finisher_queue_len, 0); | |
155 | logger->set(l_finisher_complete_lat, 0); | |
156 | } | |
157 | ||
158 | ~Finisher() { | |
159 | if (logger && cct) { | |
160 | cct->get_perfcounters_collection()->remove(logger); | |
161 | delete logger; | |
162 | } | |
163 | } | |
164 | }; | |
165 | ||
166 | /// Context that is completed asynchronously on the supplied finisher. | |
167 | class C_OnFinisher : public Context { | |
168 | Context *con; | |
169 | Finisher *fin; | |
170 | public: | |
171 | C_OnFinisher(Context *c, Finisher *f) : con(c), fin(f) { | |
172 | assert(fin != NULL); | |
173 | assert(con != NULL); | |
174 | } | |
175 | ||
176 | ~C_OnFinisher() override { | |
177 | if (con != nullptr) { | |
178 | delete con; | |
179 | con = nullptr; | |
180 | } | |
181 | } | |
182 | ||
183 | void finish(int r) override { | |
184 | fin->queue(con, r); | |
185 | con = nullptr; | |
186 | } | |
187 | }; | |
188 | ||
189 | #endif |