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) 2014 CohortFS, LLC
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 #include <string>
15 #include "QueueStrategy.h"
16 #define dout_subsys ceph_subsys_ms
17 #include "common/debug.h"
18
19 QueueStrategy::QueueStrategy(int _n_threads)
20 : n_threads(_n_threads),
21 stop(false),
22 mqueue(),
23 disp_threads()
24 {
25 }
26
27 void QueueStrategy::ds_dispatch(Message *m) {
28 msgr->ms_fast_preprocess(m);
29 if (msgr->ms_can_fast_dispatch(m)) {
30 msgr->ms_fast_dispatch(m);
31 return;
32 }
33 std::lock_guard l{lock};
34 mqueue.push_back(*m);
35 if (disp_threads.size()) {
36 if (! disp_threads.empty()) {
37 QSThread *thrd = &disp_threads.front();
38 disp_threads.pop_front();
39 thrd->cond.notify_all();
40 }
41 }
42 }
43
44 void QueueStrategy::entry(QSThread *thrd)
45 {
46 for (;;) {
47 ref_t<Message> m;
48 std::unique_lock l{lock};
49 for (;;) {
50 if (! mqueue.empty()) {
51 m = ref_t<Message>(&mqueue.front(), false);
52 mqueue.pop_front();
53 break;
54 }
55 if (stop)
56 break;
57 disp_threads.push_front(*thrd);
58 thrd->cond.wait(l);
59 }
60 l.unlock();
61 if (stop) {
62 if (!m) break;
63 continue;
64 }
65 get_messenger()->ms_deliver_dispatch(m);
66 }
67 }
68
69 void QueueStrategy::shutdown()
70 {
71 QSThread *thrd;
72 std::lock_guard l{lock};
73 stop = true;
|
(1) Event cond_true: |
Condition "this->disp_threads.size()", taking true branch. |
74 while (disp_threads.size()) {
|
(2) Event extract: |
Calling "front" which extracts wrapped state from "this->disp_threads". |
|
(3) Event assign: |
Assigning: "thrd" = "this->disp_threads.front()". |
| Also see events: |
[invalidate][use_after_free] |
75 thrd = &(disp_threads.front());
|
(4) Event invalidate: |
Calling "pop_front" invalidates the internal representation of "this->disp_threads". |
| Also see events: |
[extract][assign][use_after_free] |
76 disp_threads.pop_front();
|
(5) Event use_after_free: |
Using invalidated internal representation of "this->disp_threads". |
| Also see events: |
[extract][assign][invalidate] |
77 thrd->cond.notify_all();
78 }
79 }
80
81 void QueueStrategy::wait()
82 {
83 std::unique_lock l{lock};
84 ceph_assert(stop);
85 for (auto& thread : threads) {
86 l.unlock();
87
88 // join outside of lock
89 thread->join();
90
91 l.lock();
92 }
93 }
94
95 void QueueStrategy::start()
96 {
97 ceph_assert(!stop);
98 std::lock_guard l{lock};
99 threads.reserve(n_threads);
100 for (int ix = 0; ix < n_threads; ++ix) {
101 string thread_name = "ms_qs_";
102 thread_name.append(std::to_string(ix));
103 auto thrd = std::make_unique<QSThread>(this);
104 thrd->create(thread_name.c_str());
105 threads.emplace_back(std::move(thrd));
106 }
107 }
108