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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 | ||
29 | static struct timer_signal_data timer_signal; | |
30 | ||
31 | /* | |
32 | * Set custom signal mask to current thread. | |
33 | */ | |
34 | static void setmask(sigset_t *mask) | |
35 | { | |
36 | int ret; | |
37 | ||
38 | ret = sigemptyset(mask); | |
39 | if (ret) { | |
40 | PERROR("sigemptyset"); | |
41 | } | |
42 | ret = sigaddset(mask, LTTNG_CONSUMER_SIG_SWITCH); | |
43 | if (ret) { | |
44 | PERROR("sigaddset"); | |
45 | } | |
46 | ret = sigaddset(mask, LTTNG_CONSUMER_SIG_TEARDOWN); | |
47 | if (ret) { | |
48 | PERROR("sigaddset"); | |
49 | } | |
50 | } | |
51 | ||
52 | /* | |
53 | * Execute action on a timer switch. | |
54 | */ | |
55 | static void metadata_switch_timer(struct lttng_consumer_local_data *ctx, | |
56 | int sig, siginfo_t *si, void *uc) | |
57 | { | |
58 | int ret; | |
59 | struct lttng_consumer_channel *channel; | |
60 | ||
61 | channel = si->si_value.sival_ptr; | |
62 | assert(channel); | |
63 | ||
64 | DBG("Switch timer for channel %" PRIu64, channel->key); | |
65 | switch (ctx->type) { | |
66 | case LTTNG_CONSUMER32_UST: | |
67 | case LTTNG_CONSUMER64_UST: | |
68 | ret = lttng_ustconsumer_request_metadata(ctx, channel); | |
69 | if (ret < 0) { | |
70 | /* | |
71 | * An error means that we were unable to request the metadata to | |
72 | * the session daemon so stop the timer for that channel. | |
73 | */ | |
74 | consumer_timer_switch_stop(channel); | |
75 | } | |
76 | break; | |
77 | case LTTNG_CONSUMER_KERNEL: | |
78 | case LTTNG_CONSUMER_UNKNOWN: | |
79 | assert(0); | |
80 | break; | |
81 | } | |
82 | } | |
83 | ||
84 | /* | |
85 | * Set the timer for periodical metadata flush. | |
86 | */ | |
87 | void consumer_timer_switch_start(struct lttng_consumer_channel *channel, | |
88 | unsigned int switch_timer_interval) | |
89 | { | |
90 | int ret; | |
91 | struct sigevent sev; | |
92 | struct itimerspec its; | |
93 | ||
94 | assert(channel); | |
95 | assert(channel->key); | |
96 | ||
97 | if (switch_timer_interval == 0) { | |
98 | return; | |
99 | } | |
100 | ||
101 | sev.sigev_notify = SIGEV_SIGNAL; | |
102 | sev.sigev_signo = LTTNG_CONSUMER_SIG_SWITCH; | |
103 | sev.sigev_value.sival_ptr = channel; | |
104 | ret = timer_create(CLOCKID, &sev, &channel->switch_timer); | |
105 | if (ret == -1) { | |
106 | PERROR("timer_create"); | |
107 | } | |
108 | channel->switch_timer_enabled = 1; | |
109 | ||
110 | its.it_value.tv_sec = switch_timer_interval / 1000000; | |
111 | its.it_value.tv_nsec = switch_timer_interval % 1000000; | |
112 | its.it_interval.tv_sec = its.it_value.tv_sec; | |
113 | its.it_interval.tv_nsec = its.it_value.tv_nsec; | |
114 | ||
115 | ret = timer_settime(channel->switch_timer, 0, &its, NULL); | |
116 | if (ret == -1) { | |
117 | PERROR("timer_settime"); | |
118 | } | |
119 | } | |
120 | ||
121 | /* | |
122 | * Stop and delete timer. | |
123 | */ | |
124 | void consumer_timer_switch_stop(struct lttng_consumer_channel *channel) | |
125 | { | |
126 | int ret; | |
127 | sigset_t pending_set; | |
128 | ||
129 | assert(channel); | |
130 | ||
131 | ret = timer_delete(channel->switch_timer); | |
132 | if (ret == -1) { | |
133 | PERROR("timer_delete"); | |
134 | } | |
135 | ||
136 | /* Ensure we don't have any signal queued for this channel. */ | |
137 | for (;;) { | |
138 | ret = sigemptyset(&pending_set); | |
139 | if (ret == -1) { | |
140 | PERROR("sigemptyset"); | |
141 | } | |
142 | ret = sigpending(&pending_set); | |
143 | if (ret == -1) { | |
144 | PERROR("sigpending"); | |
145 | } | |
146 | if (!sigismember(&pending_set, LTTNG_CONSUMER_SIG_SWITCH)) { | |
147 | break; | |
148 | } | |
149 | caa_cpu_relax(); | |
150 | } | |
151 | ||
152 | /* | |
153 | * From this point, no new signal handler will be fired that would try to | |
154 | * access "chan". However, we still need to wait for any currently | |
155 | * executing handler to complete. | |
156 | */ | |
157 | cmm_smp_mb(); | |
158 | CMM_STORE_SHARED(timer_signal.qs_done, 0); | |
159 | cmm_smp_mb(); | |
160 | ||
161 | /* | |
162 | * Kill with LTTNG_CONSUMER_SIG_TEARDOWN, so signal management thread wakes | |
163 | * up. | |
164 | */ | |
165 | kill(getpid(), LTTNG_CONSUMER_SIG_TEARDOWN); | |
166 | ||
167 | while (!CMM_LOAD_SHARED(timer_signal.qs_done)) { | |
168 | caa_cpu_relax(); | |
169 | } | |
170 | cmm_smp_mb(); | |
171 | } | |
172 | ||
173 | /* | |
174 | * Block the RT signals for the entire process. It must be called from the | |
175 | * consumer main before creating the threads | |
176 | */ | |
177 | void consumer_signal_init(void) | |
178 | { | |
179 | int ret; | |
180 | sigset_t mask; | |
181 | ||
182 | /* Block signal for entire process, so only our thread processes it. */ | |
183 | setmask(&mask); | |
184 | ret = pthread_sigmask(SIG_BLOCK, &mask, NULL); | |
185 | if (ret) { | |
186 | errno = ret; | |
187 | PERROR("pthread_sigmask"); | |
188 | } | |
189 | } | |
190 | ||
191 | /* | |
192 | * This thread is the sighandler for signals LTTNG_CONSUMER_SIG_SWITCH and | |
193 | * LTTNG_CONSUMER_SIG_TEARDOWN that are emitted by the periodic timer to check | |
194 | * if new metadata is available. | |
195 | */ | |
196 | void *consumer_timer_metadata_thread(void *data) | |
197 | { | |
198 | int signr; | |
199 | sigset_t mask; | |
200 | siginfo_t info; | |
201 | struct lttng_consumer_local_data *ctx = data; | |
202 | ||
203 | /* Only self thread will receive signal mask. */ | |
204 | setmask(&mask); | |
205 | CMM_STORE_SHARED(timer_signal.tid, pthread_self()); | |
206 | ||
207 | while (1) { | |
208 | signr = sigwaitinfo(&mask, &info); | |
209 | if (signr == -1) { | |
210 | if (errno != EINTR) { | |
211 | PERROR("sigwaitinfo"); | |
212 | } | |
213 | continue; | |
214 | } else if (signr == LTTNG_CONSUMER_SIG_SWITCH) { | |
215 | metadata_switch_timer(ctx, info.si_signo, &info, NULL); | |
216 | } else if (signr == LTTNG_CONSUMER_SIG_TEARDOWN) { | |
217 | cmm_smp_mb(); | |
218 | CMM_STORE_SHARED(timer_signal.qs_done, 1); | |
219 | cmm_smp_mb(); | |
220 | DBG("Signal timer metadata thread teardown"); | |
221 | } else { | |
222 | ERR("Unexpected signal %d\n", info.si_signo); | |
223 | } | |
224 | } | |
225 | ||
226 | return NULL; | |
227 | } |