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331744e3 JD |
1 | /* |
2 | * Copyright (C) 2012 - Julien Desfossez <julien.desfossez@efficios.com> | |
3 | * David Goulet <dgoulet@efficios.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License, version 2 only, as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along with | |
15 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
16 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
17 | */ | |
18 | ||
19 | #define _GNU_SOURCE | |
20 | #include <assert.h> | |
21 | #include <inttypes.h> | |
22 | #include <signal.h> | |
23 | ||
24 | #include <common/common.h> | |
25 | ||
26 | #include "consumer-timer.h" | |
27 | #include "ust-consumer/ust-consumer.h" | |
28 | ||
2b8f8754 MD |
29 | static struct timer_signal_data timer_signal = { |
30 | .tid = 0, | |
31 | .setup_done = 0, | |
32 | .qs_done = 0, | |
33 | .lock = PTHREAD_MUTEX_INITIALIZER, | |
34 | }; | |
331744e3 JD |
35 | |
36 | /* | |
37 | * Set custom signal mask to current thread. | |
38 | */ | |
39 | static void setmask(sigset_t *mask) | |
40 | { | |
41 | int ret; | |
42 | ||
43 | ret = sigemptyset(mask); | |
44 | if (ret) { | |
45 | PERROR("sigemptyset"); | |
46 | } | |
47 | ret = sigaddset(mask, LTTNG_CONSUMER_SIG_SWITCH); | |
48 | if (ret) { | |
49 | PERROR("sigaddset"); | |
50 | } | |
51 | ret = sigaddset(mask, LTTNG_CONSUMER_SIG_TEARDOWN); | |
52 | if (ret) { | |
53 | PERROR("sigaddset"); | |
54 | } | |
55 | } | |
56 | ||
57 | /* | |
58 | * Execute action on a timer switch. | |
2755a3c6 MD |
59 | * |
60 | * Beware: metadata_switch_timer() should *never* take a mutex also held | |
61 | * while consumer_timer_switch_stop() is called. It would result in | |
62 | * deadlocks. | |
331744e3 JD |
63 | */ |
64 | static void metadata_switch_timer(struct lttng_consumer_local_data *ctx, | |
65 | int sig, siginfo_t *si, void *uc) | |
66 | { | |
67 | int ret; | |
68 | struct lttng_consumer_channel *channel; | |
69 | ||
70 | channel = si->si_value.sival_ptr; | |
71 | assert(channel); | |
72 | ||
4419b4fb MD |
73 | if (channel->switch_timer_error) { |
74 | return; | |
75 | } | |
76 | ||
331744e3 JD |
77 | DBG("Switch timer for channel %" PRIu64, channel->key); |
78 | switch (ctx->type) { | |
79 | case LTTNG_CONSUMER32_UST: | |
80 | case LTTNG_CONSUMER64_UST: | |
81 | ret = lttng_ustconsumer_request_metadata(ctx, channel); | |
82 | if (ret < 0) { | |
4419b4fb | 83 | channel->switch_timer_error = 1; |
331744e3 JD |
84 | } |
85 | break; | |
86 | case LTTNG_CONSUMER_KERNEL: | |
87 | case LTTNG_CONSUMER_UNKNOWN: | |
88 | assert(0); | |
89 | break; | |
90 | } | |
91 | } | |
92 | ||
2b8f8754 MD |
93 | static |
94 | void consumer_timer_signal_thread_qs(unsigned int signr) | |
95 | { | |
96 | sigset_t pending_set; | |
97 | int ret; | |
98 | ||
99 | /* | |
100 | * We need to be the only thread interacting with the thread | |
101 | * that manages signals for teardown synchronization. | |
102 | */ | |
103 | pthread_mutex_lock(&timer_signal.lock); | |
104 | ||
105 | /* Ensure we don't have any signal queued for this channel. */ | |
106 | for (;;) { | |
107 | ret = sigemptyset(&pending_set); | |
108 | if (ret == -1) { | |
109 | PERROR("sigemptyset"); | |
110 | } | |
111 | ret = sigpending(&pending_set); | |
112 | if (ret == -1) { | |
113 | PERROR("sigpending"); | |
114 | } | |
115 | if (!sigismember(&pending_set, LTTNG_CONSUMER_SIG_SWITCH)) { | |
116 | break; | |
117 | } | |
118 | caa_cpu_relax(); | |
119 | } | |
120 | ||
121 | /* | |
122 | * From this point, no new signal handler will be fired that would try to | |
123 | * access "chan". However, we still need to wait for any currently | |
124 | * executing handler to complete. | |
125 | */ | |
126 | cmm_smp_mb(); | |
127 | CMM_STORE_SHARED(timer_signal.qs_done, 0); | |
128 | cmm_smp_mb(); | |
129 | ||
130 | /* | |
131 | * Kill with LTTNG_CONSUMER_SIG_TEARDOWN, so signal management thread wakes | |
132 | * up. | |
133 | */ | |
134 | kill(getpid(), LTTNG_CONSUMER_SIG_TEARDOWN); | |
135 | ||
136 | while (!CMM_LOAD_SHARED(timer_signal.qs_done)) { | |
137 | caa_cpu_relax(); | |
138 | } | |
139 | cmm_smp_mb(); | |
140 | ||
141 | pthread_mutex_unlock(&timer_signal.lock); | |
142 | } | |
143 | ||
331744e3 JD |
144 | /* |
145 | * Set the timer for periodical metadata flush. | |
146 | */ | |
147 | void consumer_timer_switch_start(struct lttng_consumer_channel *channel, | |
148 | unsigned int switch_timer_interval) | |
149 | { | |
150 | int ret; | |
151 | struct sigevent sev; | |
152 | struct itimerspec its; | |
153 | ||
154 | assert(channel); | |
155 | assert(channel->key); | |
156 | ||
157 | if (switch_timer_interval == 0) { | |
158 | return; | |
159 | } | |
160 | ||
161 | sev.sigev_notify = SIGEV_SIGNAL; | |
162 | sev.sigev_signo = LTTNG_CONSUMER_SIG_SWITCH; | |
163 | sev.sigev_value.sival_ptr = channel; | |
164 | ret = timer_create(CLOCKID, &sev, &channel->switch_timer); | |
165 | if (ret == -1) { | |
166 | PERROR("timer_create"); | |
167 | } | |
168 | channel->switch_timer_enabled = 1; | |
169 | ||
170 | its.it_value.tv_sec = switch_timer_interval / 1000000; | |
171 | its.it_value.tv_nsec = switch_timer_interval % 1000000; | |
172 | its.it_interval.tv_sec = its.it_value.tv_sec; | |
173 | its.it_interval.tv_nsec = its.it_value.tv_nsec; | |
174 | ||
175 | ret = timer_settime(channel->switch_timer, 0, &its, NULL); | |
176 | if (ret == -1) { | |
177 | PERROR("timer_settime"); | |
178 | } | |
179 | } | |
180 | ||
181 | /* | |
182 | * Stop and delete timer. | |
183 | */ | |
184 | void consumer_timer_switch_stop(struct lttng_consumer_channel *channel) | |
185 | { | |
186 | int ret; | |
331744e3 JD |
187 | |
188 | assert(channel); | |
189 | ||
190 | ret = timer_delete(channel->switch_timer); | |
191 | if (ret == -1) { | |
192 | PERROR("timer_delete"); | |
193 | } | |
194 | ||
2b8f8754 | 195 | consumer_timer_signal_thread_qs(LTTNG_CONSUMER_SIG_SWITCH); |
331744e3 | 196 | |
2b8f8754 MD |
197 | channel->switch_timer = 0; |
198 | channel->switch_timer_enabled = 0; | |
331744e3 JD |
199 | } |
200 | ||
201 | /* | |
202 | * Block the RT signals for the entire process. It must be called from the | |
203 | * consumer main before creating the threads | |
204 | */ | |
205 | void consumer_signal_init(void) | |
206 | { | |
207 | int ret; | |
208 | sigset_t mask; | |
209 | ||
210 | /* Block signal for entire process, so only our thread processes it. */ | |
211 | setmask(&mask); | |
212 | ret = pthread_sigmask(SIG_BLOCK, &mask, NULL); | |
213 | if (ret) { | |
214 | errno = ret; | |
215 | PERROR("pthread_sigmask"); | |
216 | } | |
217 | } | |
218 | ||
219 | /* | |
220 | * This thread is the sighandler for signals LTTNG_CONSUMER_SIG_SWITCH and | |
221 | * LTTNG_CONSUMER_SIG_TEARDOWN that are emitted by the periodic timer to check | |
222 | * if new metadata is available. | |
223 | */ | |
224 | void *consumer_timer_metadata_thread(void *data) | |
225 | { | |
226 | int signr; | |
227 | sigset_t mask; | |
228 | siginfo_t info; | |
229 | struct lttng_consumer_local_data *ctx = data; | |
230 | ||
231 | /* Only self thread will receive signal mask. */ | |
232 | setmask(&mask); | |
233 | CMM_STORE_SHARED(timer_signal.tid, pthread_self()); | |
234 | ||
235 | while (1) { | |
236 | signr = sigwaitinfo(&mask, &info); | |
237 | if (signr == -1) { | |
238 | if (errno != EINTR) { | |
239 | PERROR("sigwaitinfo"); | |
240 | } | |
241 | continue; | |
242 | } else if (signr == LTTNG_CONSUMER_SIG_SWITCH) { | |
243 | metadata_switch_timer(ctx, info.si_signo, &info, NULL); | |
244 | } else if (signr == LTTNG_CONSUMER_SIG_TEARDOWN) { | |
245 | cmm_smp_mb(); | |
246 | CMM_STORE_SHARED(timer_signal.qs_done, 1); | |
247 | cmm_smp_mb(); | |
248 | DBG("Signal timer metadata thread teardown"); | |
249 | } else { | |
250 | ERR("Unexpected signal %d\n", info.si_signo); | |
251 | } | |
252 | } | |
253 | ||
254 | return NULL; | |
255 | } |