Commit | Line | Data |
---|---|---|
5b093681 | 1 | /* |
21cf9b6b | 2 | * Copyright (C) 2011 EfficiOS Inc. |
ab5be9fa MJ |
3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
4 | * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
5b093681 | 5 | * |
ab5be9fa | 6 | * SPDX-License-Identifier: GPL-2.0-only |
5b093681 | 7 | * |
5b093681 JG |
8 | */ |
9 | ||
28ab034a JG |
10 | #include "health-sessiond.hpp" |
11 | #include "kernel-consumer.hpp" | |
12 | #include "kernel.hpp" | |
c9e313bc SM |
13 | #include "manage-kernel.hpp" |
14 | #include "testpoint.hpp" | |
c9e313bc | 15 | #include "thread.hpp" |
28ab034a JG |
16 | #include "utils.hpp" |
17 | ||
18 | #include <common/pipe.hpp> | |
19 | #include <common/utils.hpp> | |
5b093681 | 20 | |
f1494934 | 21 | namespace { |
5b093681 JG |
22 | struct thread_notifiers { |
23 | struct lttng_pipe *quit_pipe; | |
24 | int kernel_poll_pipe_read_fd; | |
25 | }; | |
f1494934 | 26 | } /* namespace */ |
5b093681 JG |
27 | |
28 | /* | |
29 | * Update the kernel poll set of all channel fd available over all tracing | |
30 | * session. Add the wakeup pipe at the end of the set. | |
31 | */ | |
32 | static int update_kernel_poll(struct lttng_poll_event *events) | |
33 | { | |
34 | int ret; | |
35 | struct ltt_kernel_channel *channel; | |
36 | struct ltt_session *session; | |
37 | const struct ltt_session_list *session_list = session_get_list(); | |
38 | ||
39 | DBG("Updating kernel poll set"); | |
40 | ||
41 | session_lock_list(); | |
28ab034a | 42 | cds_list_for_each_entry (session, &session_list->head, list) { |
5b093681 JG |
43 | if (!session_get(session)) { |
44 | continue; | |
45 | } | |
46 | session_lock(session); | |
cd9adb8b | 47 | if (session->kernel_session == nullptr) { |
5b093681 JG |
48 | session_unlock(session); |
49 | session_put(session); | |
50 | continue; | |
51 | } | |
52 | ||
28ab034a JG |
53 | cds_list_for_each_entry ( |
54 | channel, &session->kernel_session->channel_list.head, list) { | |
5b093681 JG |
55 | /* Add channel fd to the kernel poll set */ |
56 | ret = lttng_poll_add(events, channel->fd, LPOLLIN | LPOLLRDNORM); | |
57 | if (ret < 0) { | |
58 | session_unlock(session); | |
59 | session_put(session); | |
60 | goto error; | |
61 | } | |
62 | DBG("Channel fd %d added to kernel set", channel->fd); | |
63 | } | |
64 | session_unlock(session); | |
0318876b | 65 | session_put(session); |
5b093681 JG |
66 | } |
67 | session_unlock_list(); | |
68 | ||
69 | return 0; | |
70 | ||
71 | error: | |
72 | session_unlock_list(); | |
73 | return -1; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Find the channel fd from 'fd' over all tracing session. When found, check | |
78 | * for new channel stream and send those stream fds to the kernel consumer. | |
79 | * | |
80 | * Useful for CPU hotplug feature. | |
81 | */ | |
82 | static int update_kernel_stream(int fd) | |
83 | { | |
84 | int ret = 0; | |
85 | struct ltt_session *session; | |
86 | struct ltt_kernel_session *ksess; | |
87 | struct ltt_kernel_channel *channel; | |
88 | const struct ltt_session_list *session_list = session_get_list(); | |
89 | ||
90 | DBG("Updating kernel streams for channel fd %d", fd); | |
91 | ||
92 | session_lock_list(); | |
28ab034a | 93 | cds_list_for_each_entry (session, &session_list->head, list) { |
5b093681 JG |
94 | if (!session_get(session)) { |
95 | continue; | |
96 | } | |
97 | session_lock(session); | |
cd9adb8b | 98 | if (session->kernel_session == nullptr) { |
5b093681 JG |
99 | session_unlock(session); |
100 | session_put(session); | |
101 | continue; | |
102 | } | |
103 | ksess = session->kernel_session; | |
104 | ||
28ab034a | 105 | cds_list_for_each_entry (channel, &ksess->channel_list.head, list) { |
5b093681 JG |
106 | struct lttng_ht_iter iter; |
107 | struct consumer_socket *socket; | |
108 | ||
109 | if (channel->fd != fd) { | |
110 | continue; | |
111 | } | |
112 | DBG("Channel found, updating kernel streams"); | |
113 | ret = kernel_open_channel_stream(channel); | |
114 | if (ret < 0) { | |
115 | goto error; | |
116 | } | |
117 | /* Update the stream global counter */ | |
118 | ksess->stream_count_global += ret; | |
119 | ||
120 | /* | |
121 | * Have we already sent fds to the consumer? If yes, it | |
122 | * means that tracing is started so it is safe to send | |
123 | * our updated stream fds. | |
124 | */ | |
cd9adb8b | 125 | if (ksess->consumer_fds_sent != 1 || ksess->consumer == nullptr) { |
5b093681 JG |
126 | ret = -1; |
127 | goto error; | |
128 | } | |
129 | ||
130 | rcu_read_lock(); | |
28ab034a JG |
131 | cds_lfht_for_each_entry ( |
132 | ksess->consumer->socks->ht, &iter.iter, socket, node.node) { | |
5b093681 | 133 | pthread_mutex_lock(socket->lock); |
28ab034a JG |
134 | ret = kernel_consumer_send_channel_streams( |
135 | socket, channel, ksess, session->output_traces ? 1 : 0); | |
5b093681 JG |
136 | pthread_mutex_unlock(socket->lock); |
137 | if (ret < 0) { | |
138 | rcu_read_unlock(); | |
139 | goto error; | |
140 | } | |
141 | } | |
142 | rcu_read_unlock(); | |
143 | } | |
144 | session_unlock(session); | |
145 | session_put(session); | |
146 | } | |
147 | session_unlock_list(); | |
148 | return ret; | |
149 | ||
150 | error: | |
151 | session_unlock(session); | |
152 | session_put(session); | |
153 | session_unlock_list(); | |
154 | return ret; | |
155 | } | |
156 | ||
157 | /* | |
158 | * This thread manage event coming from the kernel. | |
159 | * | |
160 | * Features supported in this thread: | |
161 | * -) CPU Hotplug | |
162 | */ | |
163 | static void *thread_kernel_management(void *data) | |
164 | { | |
8a00688e MJ |
165 | int ret, i, update_poll_flag = 1, err = -1; |
166 | uint32_t nb_fd; | |
5b093681 JG |
167 | char tmp; |
168 | struct lttng_poll_event events; | |
7966af57 | 169 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
8a00688e | 170 | const auto thread_quit_pipe_fd = lttng_pipe_get_readfd(notifiers->quit_pipe); |
5b093681 JG |
171 | |
172 | DBG("[thread] Thread manage kernel started"); | |
173 | ||
412d7227 | 174 | health_register(the_health_sessiond, HEALTH_SESSIOND_TYPE_KERNEL); |
5b093681 JG |
175 | |
176 | /* | |
177 | * This first step of the while is to clean this structure which could free | |
178 | * non NULL pointers so initialize it before the loop. | |
179 | */ | |
180 | lttng_poll_init(&events); | |
181 | ||
182 | if (testpoint(sessiond_thread_manage_kernel)) { | |
183 | goto error_testpoint; | |
184 | } | |
185 | ||
186 | health_code_update(); | |
187 | ||
188 | if (testpoint(sessiond_thread_manage_kernel_before_loop)) { | |
189 | goto error_testpoint; | |
190 | } | |
191 | ||
cd9adb8b | 192 | while (true) { |
5b093681 JG |
193 | health_code_update(); |
194 | ||
195 | if (update_poll_flag == 1) { | |
196 | /* Clean events object. We are about to populate it again. */ | |
197 | lttng_poll_clean(&events); | |
198 | ||
199 | ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); | |
200 | if (ret < 0) { | |
201 | goto error_poll_create; | |
202 | } | |
203 | ||
28ab034a | 204 | ret = lttng_poll_add(&events, notifiers->kernel_poll_pipe_read_fd, LPOLLIN); |
5b093681 JG |
205 | if (ret < 0) { |
206 | goto error; | |
207 | } | |
208 | ||
28ab034a | 209 | ret = lttng_poll_add(&events, thread_quit_pipe_fd, LPOLLIN); |
5b093681 JG |
210 | if (ret < 0) { |
211 | goto error; | |
212 | } | |
213 | ||
214 | /* This will add the available kernel channel if any. */ | |
215 | ret = update_kernel_poll(&events); | |
216 | if (ret < 0) { | |
217 | goto error; | |
218 | } | |
219 | update_poll_flag = 0; | |
220 | } | |
221 | ||
222 | DBG("Thread kernel polling"); | |
223 | ||
224 | /* Poll infinite value of time */ | |
225 | restart: | |
226 | health_poll_entry(); | |
227 | ret = lttng_poll_wait(&events, -1); | |
28ab034a | 228 | DBG("Thread kernel return from poll on %d fds", LTTNG_POLL_GETNB(&events)); |
5b093681 JG |
229 | health_poll_exit(); |
230 | if (ret < 0) { | |
231 | /* | |
232 | * Restart interrupted system call. | |
233 | */ | |
234 | if (errno == EINTR) { | |
235 | goto restart; | |
236 | } | |
237 | goto error; | |
238 | } else if (ret == 0) { | |
239 | /* Should not happen since timeout is infinite */ | |
240 | ERR("Return value of poll is 0 with an infinite timeout.\n" | |
28ab034a | 241 | "This should not have happened! Continuing..."); |
5b093681 JG |
242 | continue; |
243 | } | |
244 | ||
245 | nb_fd = ret; | |
246 | ||
247 | for (i = 0; i < nb_fd; i++) { | |
248 | /* Fetch once the poll data */ | |
8a00688e MJ |
249 | const auto revents = LTTNG_POLL_GETEV(&events, i); |
250 | const auto pollfd = LTTNG_POLL_GETFD(&events, i); | |
5b093681 JG |
251 | |
252 | health_code_update(); | |
253 | ||
8a00688e MJ |
254 | /* Activity on thread quit pipe, exiting. */ |
255 | if (pollfd == thread_quit_pipe_fd) { | |
256 | DBG("Activity on thread quit pipe"); | |
5b093681 JG |
257 | err = 0; |
258 | goto exit; | |
259 | } | |
260 | ||
261 | /* Check for data on kernel pipe */ | |
262 | if (revents & LPOLLIN) { | |
263 | if (pollfd == notifiers->kernel_poll_pipe_read_fd) { | |
28ab034a JG |
264 | (void) lttng_read( |
265 | notifiers->kernel_poll_pipe_read_fd, &tmp, 1); | |
5b093681 | 266 | /* |
28ab034a JG |
267 | * Ret value is useless here, if this pipe gets any actions |
268 | * an update is required anyway. | |
5b093681 JG |
269 | */ |
270 | update_poll_flag = 1; | |
271 | continue; | |
272 | } else { | |
273 | /* | |
274 | * New CPU detected by the kernel. Adding kernel stream to | |
275 | * kernel session and updating the kernel consumer | |
276 | */ | |
277 | ret = update_kernel_stream(pollfd); | |
278 | if (ret < 0) { | |
279 | continue; | |
280 | } | |
281 | break; | |
282 | } | |
283 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { | |
284 | update_poll_flag = 1; | |
285 | continue; | |
286 | } else { | |
287 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); | |
288 | goto error; | |
289 | } | |
290 | } | |
291 | } | |
292 | ||
293 | exit: | |
294 | error: | |
295 | lttng_poll_clean(&events); | |
296 | error_poll_create: | |
297 | error_testpoint: | |
298 | if (err) { | |
299 | health_error(); | |
300 | ERR("Health error occurred in %s", __func__); | |
301 | WARN("Kernel thread died unexpectedly. " | |
28ab034a | 302 | "Kernel tracing can continue but CPU hotplug is disabled."); |
5b093681 | 303 | } |
412d7227 | 304 | health_unregister(the_health_sessiond); |
5b093681 | 305 | DBG("Kernel thread dying"); |
cd9adb8b | 306 | return nullptr; |
5b093681 JG |
307 | } |
308 | ||
309 | static bool shutdown_kernel_management_thread(void *data) | |
310 | { | |
7966af57 | 311 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
5b093681 JG |
312 | const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe); |
313 | ||
314 | return notify_thread_pipe(write_fd) == 1; | |
315 | } | |
316 | ||
317 | static void cleanup_kernel_management_thread(void *data) | |
318 | { | |
7966af57 | 319 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
5b093681 JG |
320 | |
321 | lttng_pipe_destroy(notifiers->quit_pipe); | |
322 | free(notifiers); | |
323 | } | |
324 | ||
325 | bool launch_kernel_management_thread(int kernel_poll_pipe_read_fd) | |
326 | { | |
327 | struct lttng_pipe *quit_pipe; | |
cd9adb8b | 328 | struct thread_notifiers *notifiers = nullptr; |
5b093681 JG |
329 | struct lttng_thread *thread; |
330 | ||
64803277 | 331 | notifiers = zmalloc<thread_notifiers>(); |
5b093681 | 332 | if (!notifiers) { |
21fa020e JG |
333 | goto error_alloc; |
334 | } | |
335 | quit_pipe = lttng_pipe_open(FD_CLOEXEC); | |
336 | if (!quit_pipe) { | |
5b093681 JG |
337 | goto error; |
338 | } | |
339 | notifiers->quit_pipe = quit_pipe; | |
340 | notifiers->kernel_poll_pipe_read_fd = kernel_poll_pipe_read_fd; | |
341 | ||
342 | thread = lttng_thread_create("Kernel management", | |
28ab034a JG |
343 | thread_kernel_management, |
344 | shutdown_kernel_management_thread, | |
345 | cleanup_kernel_management_thread, | |
346 | notifiers); | |
5b093681 JG |
347 | if (!thread) { |
348 | goto error; | |
349 | } | |
350 | lttng_thread_put(thread); | |
351 | return true; | |
352 | error: | |
353 | cleanup_kernel_management_thread(notifiers); | |
21fa020e | 354 | error_alloc: |
5b093681 JG |
355 | return false; |
356 | } |