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> | |
56047f5a | 19 | #include <common/urcu.hpp> |
28ab034a | 20 | #include <common/utils.hpp> |
5b093681 | 21 | |
671e39d7 MJ |
22 | #include <fcntl.h> |
23 | ||
f1494934 | 24 | namespace { |
5b093681 JG |
25 | struct thread_notifiers { |
26 | struct lttng_pipe *quit_pipe; | |
27 | int kernel_poll_pipe_read_fd; | |
28 | }; | |
f1494934 | 29 | } /* namespace */ |
5b093681 JG |
30 | |
31 | /* | |
32 | * Update the kernel poll set of all channel fd available over all tracing | |
33 | * session. Add the wakeup pipe at the end of the set. | |
34 | */ | |
35 | static int update_kernel_poll(struct lttng_poll_event *events) | |
36 | { | |
37 | int ret; | |
38 | struct ltt_kernel_channel *channel; | |
39 | struct ltt_session *session; | |
40 | const struct ltt_session_list *session_list = session_get_list(); | |
41 | ||
42 | DBG("Updating kernel poll set"); | |
43 | ||
44 | session_lock_list(); | |
28ab034a | 45 | cds_list_for_each_entry (session, &session_list->head, list) { |
5b093681 JG |
46 | if (!session_get(session)) { |
47 | continue; | |
48 | } | |
49 | session_lock(session); | |
cd9adb8b | 50 | if (session->kernel_session == nullptr) { |
5b093681 JG |
51 | session_unlock(session); |
52 | session_put(session); | |
53 | continue; | |
54 | } | |
55 | ||
28ab034a JG |
56 | cds_list_for_each_entry ( |
57 | channel, &session->kernel_session->channel_list.head, list) { | |
5b093681 JG |
58 | /* Add channel fd to the kernel poll set */ |
59 | ret = lttng_poll_add(events, channel->fd, LPOLLIN | LPOLLRDNORM); | |
60 | if (ret < 0) { | |
61 | session_unlock(session); | |
62 | session_put(session); | |
63 | goto error; | |
64 | } | |
65 | DBG("Channel fd %d added to kernel set", channel->fd); | |
66 | } | |
67 | session_unlock(session); | |
0318876b | 68 | session_put(session); |
5b093681 JG |
69 | } |
70 | session_unlock_list(); | |
71 | ||
72 | return 0; | |
73 | ||
74 | error: | |
75 | session_unlock_list(); | |
76 | return -1; | |
77 | } | |
78 | ||
79 | /* | |
80 | * Find the channel fd from 'fd' over all tracing session. When found, check | |
81 | * for new channel stream and send those stream fds to the kernel consumer. | |
82 | * | |
83 | * Useful for CPU hotplug feature. | |
84 | */ | |
85 | static int update_kernel_stream(int fd) | |
86 | { | |
87 | int ret = 0; | |
88 | struct ltt_session *session; | |
89 | struct ltt_kernel_session *ksess; | |
90 | struct ltt_kernel_channel *channel; | |
91 | const struct ltt_session_list *session_list = session_get_list(); | |
92 | ||
93 | DBG("Updating kernel streams for channel fd %d", fd); | |
94 | ||
95 | session_lock_list(); | |
28ab034a | 96 | cds_list_for_each_entry (session, &session_list->head, list) { |
5b093681 JG |
97 | if (!session_get(session)) { |
98 | continue; | |
99 | } | |
56047f5a | 100 | |
5b093681 | 101 | session_lock(session); |
cd9adb8b | 102 | if (session->kernel_session == nullptr) { |
5b093681 JG |
103 | session_unlock(session); |
104 | session_put(session); | |
105 | continue; | |
106 | } | |
56047f5a | 107 | |
5b093681 JG |
108 | ksess = session->kernel_session; |
109 | ||
28ab034a | 110 | cds_list_for_each_entry (channel, &ksess->channel_list.head, list) { |
5b093681 JG |
111 | struct lttng_ht_iter iter; |
112 | struct consumer_socket *socket; | |
113 | ||
114 | if (channel->fd != fd) { | |
115 | continue; | |
116 | } | |
117 | DBG("Channel found, updating kernel streams"); | |
118 | ret = kernel_open_channel_stream(channel); | |
119 | if (ret < 0) { | |
120 | goto error; | |
121 | } | |
122 | /* Update the stream global counter */ | |
123 | ksess->stream_count_global += ret; | |
124 | ||
125 | /* | |
126 | * Have we already sent fds to the consumer? If yes, it | |
127 | * means that tracing is started so it is safe to send | |
128 | * our updated stream fds. | |
129 | */ | |
cd9adb8b | 130 | if (ksess->consumer_fds_sent != 1 || ksess->consumer == nullptr) { |
5b093681 JG |
131 | ret = -1; |
132 | goto error; | |
133 | } | |
134 | ||
56047f5a JG |
135 | { |
136 | lttng::urcu::read_lock_guard read_lock; | |
137 | ||
138 | cds_lfht_for_each_entry ( | |
139 | ksess->consumer->socks->ht, &iter.iter, socket, node.node) { | |
140 | pthread_mutex_lock(socket->lock); | |
141 | ret = kernel_consumer_send_channel_streams( | |
142 | socket, | |
143 | channel, | |
144 | ksess, | |
145 | session->output_traces ? 1 : 0); | |
146 | pthread_mutex_unlock(socket->lock); | |
147 | if (ret < 0) { | |
148 | goto error; | |
149 | } | |
5b093681 JG |
150 | } |
151 | } | |
5b093681 | 152 | } |
56047f5a | 153 | |
5b093681 JG |
154 | session_unlock(session); |
155 | session_put(session); | |
156 | } | |
157 | session_unlock_list(); | |
158 | return ret; | |
159 | ||
160 | error: | |
161 | session_unlock(session); | |
162 | session_put(session); | |
163 | session_unlock_list(); | |
164 | return ret; | |
165 | } | |
166 | ||
167 | /* | |
168 | * This thread manage event coming from the kernel. | |
169 | * | |
170 | * Features supported in this thread: | |
171 | * -) CPU Hotplug | |
172 | */ | |
173 | static void *thread_kernel_management(void *data) | |
174 | { | |
8a00688e MJ |
175 | int ret, i, update_poll_flag = 1, err = -1; |
176 | uint32_t nb_fd; | |
5b093681 JG |
177 | char tmp; |
178 | struct lttng_poll_event events; | |
7966af57 | 179 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
8a00688e | 180 | const auto thread_quit_pipe_fd = lttng_pipe_get_readfd(notifiers->quit_pipe); |
5b093681 JG |
181 | |
182 | DBG("[thread] Thread manage kernel started"); | |
183 | ||
412d7227 | 184 | health_register(the_health_sessiond, HEALTH_SESSIOND_TYPE_KERNEL); |
5b093681 JG |
185 | |
186 | /* | |
187 | * This first step of the while is to clean this structure which could free | |
188 | * non NULL pointers so initialize it before the loop. | |
189 | */ | |
190 | lttng_poll_init(&events); | |
191 | ||
192 | if (testpoint(sessiond_thread_manage_kernel)) { | |
193 | goto error_testpoint; | |
194 | } | |
195 | ||
196 | health_code_update(); | |
197 | ||
198 | if (testpoint(sessiond_thread_manage_kernel_before_loop)) { | |
199 | goto error_testpoint; | |
200 | } | |
201 | ||
cd9adb8b | 202 | while (true) { |
5b093681 JG |
203 | health_code_update(); |
204 | ||
205 | if (update_poll_flag == 1) { | |
206 | /* Clean events object. We are about to populate it again. */ | |
207 | lttng_poll_clean(&events); | |
208 | ||
209 | ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); | |
210 | if (ret < 0) { | |
211 | goto error_poll_create; | |
212 | } | |
213 | ||
28ab034a | 214 | ret = lttng_poll_add(&events, notifiers->kernel_poll_pipe_read_fd, LPOLLIN); |
5b093681 JG |
215 | if (ret < 0) { |
216 | goto error; | |
217 | } | |
218 | ||
28ab034a | 219 | ret = lttng_poll_add(&events, thread_quit_pipe_fd, LPOLLIN); |
5b093681 JG |
220 | if (ret < 0) { |
221 | goto error; | |
222 | } | |
223 | ||
224 | /* This will add the available kernel channel if any. */ | |
225 | ret = update_kernel_poll(&events); | |
226 | if (ret < 0) { | |
227 | goto error; | |
228 | } | |
229 | update_poll_flag = 0; | |
230 | } | |
231 | ||
232 | DBG("Thread kernel polling"); | |
233 | ||
234 | /* Poll infinite value of time */ | |
235 | restart: | |
236 | health_poll_entry(); | |
237 | ret = lttng_poll_wait(&events, -1); | |
28ab034a | 238 | DBG("Thread kernel return from poll on %d fds", LTTNG_POLL_GETNB(&events)); |
5b093681 JG |
239 | health_poll_exit(); |
240 | if (ret < 0) { | |
241 | /* | |
242 | * Restart interrupted system call. | |
243 | */ | |
244 | if (errno == EINTR) { | |
245 | goto restart; | |
246 | } | |
247 | goto error; | |
248 | } else if (ret == 0) { | |
249 | /* Should not happen since timeout is infinite */ | |
250 | ERR("Return value of poll is 0 with an infinite timeout.\n" | |
28ab034a | 251 | "This should not have happened! Continuing..."); |
5b093681 JG |
252 | continue; |
253 | } | |
254 | ||
255 | nb_fd = ret; | |
256 | ||
257 | for (i = 0; i < nb_fd; i++) { | |
258 | /* Fetch once the poll data */ | |
8a00688e MJ |
259 | const auto revents = LTTNG_POLL_GETEV(&events, i); |
260 | const auto pollfd = LTTNG_POLL_GETFD(&events, i); | |
5b093681 JG |
261 | |
262 | health_code_update(); | |
263 | ||
8a00688e MJ |
264 | /* Activity on thread quit pipe, exiting. */ |
265 | if (pollfd == thread_quit_pipe_fd) { | |
266 | DBG("Activity on thread quit pipe"); | |
5b093681 JG |
267 | err = 0; |
268 | goto exit; | |
269 | } | |
270 | ||
271 | /* Check for data on kernel pipe */ | |
272 | if (revents & LPOLLIN) { | |
273 | if (pollfd == notifiers->kernel_poll_pipe_read_fd) { | |
28ab034a JG |
274 | (void) lttng_read( |
275 | notifiers->kernel_poll_pipe_read_fd, &tmp, 1); | |
5b093681 | 276 | /* |
28ab034a JG |
277 | * Ret value is useless here, if this pipe gets any actions |
278 | * an update is required anyway. | |
5b093681 JG |
279 | */ |
280 | update_poll_flag = 1; | |
281 | continue; | |
282 | } else { | |
283 | /* | |
284 | * New CPU detected by the kernel. Adding kernel stream to | |
285 | * kernel session and updating the kernel consumer | |
286 | */ | |
287 | ret = update_kernel_stream(pollfd); | |
288 | if (ret < 0) { | |
289 | continue; | |
290 | } | |
291 | break; | |
292 | } | |
293 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { | |
294 | update_poll_flag = 1; | |
295 | continue; | |
296 | } else { | |
297 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); | |
298 | goto error; | |
299 | } | |
300 | } | |
301 | } | |
302 | ||
303 | exit: | |
304 | error: | |
305 | lttng_poll_clean(&events); | |
306 | error_poll_create: | |
307 | error_testpoint: | |
308 | if (err) { | |
309 | health_error(); | |
310 | ERR("Health error occurred in %s", __func__); | |
311 | WARN("Kernel thread died unexpectedly. " | |
28ab034a | 312 | "Kernel tracing can continue but CPU hotplug is disabled."); |
5b093681 | 313 | } |
412d7227 | 314 | health_unregister(the_health_sessiond); |
5b093681 | 315 | DBG("Kernel thread dying"); |
cd9adb8b | 316 | return nullptr; |
5b093681 JG |
317 | } |
318 | ||
319 | static bool shutdown_kernel_management_thread(void *data) | |
320 | { | |
7966af57 | 321 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
5b093681 JG |
322 | const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe); |
323 | ||
324 | return notify_thread_pipe(write_fd) == 1; | |
325 | } | |
326 | ||
327 | static void cleanup_kernel_management_thread(void *data) | |
328 | { | |
7966af57 | 329 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
5b093681 JG |
330 | |
331 | lttng_pipe_destroy(notifiers->quit_pipe); | |
332 | free(notifiers); | |
333 | } | |
334 | ||
335 | bool launch_kernel_management_thread(int kernel_poll_pipe_read_fd) | |
336 | { | |
337 | struct lttng_pipe *quit_pipe; | |
cd9adb8b | 338 | struct thread_notifiers *notifiers = nullptr; |
5b093681 JG |
339 | struct lttng_thread *thread; |
340 | ||
64803277 | 341 | notifiers = zmalloc<thread_notifiers>(); |
5b093681 | 342 | if (!notifiers) { |
21fa020e JG |
343 | goto error_alloc; |
344 | } | |
345 | quit_pipe = lttng_pipe_open(FD_CLOEXEC); | |
346 | if (!quit_pipe) { | |
5b093681 JG |
347 | goto error; |
348 | } | |
349 | notifiers->quit_pipe = quit_pipe; | |
350 | notifiers->kernel_poll_pipe_read_fd = kernel_poll_pipe_read_fd; | |
351 | ||
352 | thread = lttng_thread_create("Kernel management", | |
28ab034a JG |
353 | thread_kernel_management, |
354 | shutdown_kernel_management_thread, | |
355 | cleanup_kernel_management_thread, | |
356 | notifiers); | |
5b093681 JG |
357 | if (!thread) { |
358 | goto error; | |
359 | } | |
360 | lttng_thread_put(thread); | |
361 | return true; | |
362 | error: | |
363 | cleanup_kernel_management_thread(notifiers); | |
21fa020e | 364 | error_alloc: |
5b093681 JG |
365 | return false; |
366 | } |