Cleanup: sessiond: rename the sessiond main thread quit pipe

Rename the sessiond main thread 'thread_quit_pipe' as the
'main_quit_pipe' to make it easier to distinguish it from the other
threads quit pipes.

While we're there, adjust some debug statements and internal function
names to distinguish between notifying the quit pipe and actually
stopping the threads.

Change-Id: I9caf81f6d03805658e2470a026b15dde03f2a88b
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng-sessiond/lttng-sessiond.hpp b/src/bin/lttng-sessiond/lttng-sessiond.hpp
index fa4601d695405df8e1ad705d9aa0c31b525bda64..e94dd7a56eb825710cfbcf482615edf026f6f2db 100644 (file)
--- a/src/bin/lttng-sessiond/lttng-sessiond.hpp
+++ b/src/bin/lttng-sessiond/lttng-sessiond.hpp
@@ -140,11 +140,10 @@ extern struct consumer_data the_ustconsumer32_data;
 extern struct consumer_data the_ustconsumer64_data;
 extern struct consumer_data the_kconsumer_data;
 
 extern struct consumer_data the_ustconsumer64_data;
 extern struct consumer_data the_kconsumer_data;
 

-int sessiond_init_thread_quit_pipe(void);
-int sessiond_check_thread_quit_pipe(int fd, uint32_t events);
-int sessiond_wait_for_quit_pipe(int timeout_ms);
-int sessiond_notify_quit_pipe(void);
-void sessiond_close_quit_pipe(void);
+int sessiond_init_main_quit_pipe(void);
+int sessiond_wait_for_main_quit_pipe(int timeout_ms);
+int sessiond_notify_main_quit_pipe(void);
+void sessiond_close_main_quit_pipe(void);

 
 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 void sessiond_signal_parents(void);
 
 int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size);
 void sessiond_signal_parents(void);

diff --git a/src/bin/lttng-sessiond/main.cpp b/src/bin/lttng-sessiond/main.cpp
index cf7aa9e9e67bc94c971982133ef8ea49ed7fd128..23136f7c8deab6aa4677d51b9b40908b0c76edfd 100644 (file)
--- a/src/bin/lttng-sessiond/main.cpp
+++ b/src/bin/lttng-sessiond/main.cpp
@@ -166,17 +166,18 @@ static const char * const config_section_name = "sessiond";
 static int is_root;
 
 /*
 static int is_root;
 
 /*

- * Stop all threads by closing the thread quit pipe.
+ * Notify the main thread to initiate the teardown of the worker threads by
+ * writing to the main quit pipe.

  */
  */

-static void stop_threads(void)
+static void notify_main_quit_pipe(void)

 {
        int ret;
 
        /* Stopping all threads */
 {
        int ret;
 
        /* Stopping all threads */

-       DBG("Terminating all threads");
-       ret = sessiond_notify_quit_pipe();
+       DBG("Notify the main thread to terminate all worker threads");
+       ret = sessiond_notify_main_quit_pipe();

        if (ret < 0) {
        if (ret < 0) {

-               ERR("write error on thread quit pipe");
+               ERR("write error on main quit pipe");

        }
 }
 
        }
 }
 


@@ -281,10 +282,12 @@ static void sessiond_cleanup(void)
        DBG("Cleanup sessiond");
 
        /*
        DBG("Cleanup sessiond");
 
        /*

-        * Close the thread quit pipe. It has already done its job,
-        * since we are now called.
+        * Close the main quit pipe. It has already done its job, since we are
+        * now cleaning up.

         */
         */

-       sessiond_close_quit_pipe();
+       sessiond_close_main_quit_pipe();
+
+       /* Close all other pipes. */

        utils_close_pipe(apps_cmd_pipe);
        utils_close_pipe(apps_cmd_notify_pipe);
        utils_close_pipe(the_kernel_poll_pipe);
        utils_close_pipe(apps_cmd_pipe);
        utils_close_pipe(apps_cmd_notify_pipe);
        utils_close_pipe(the_kernel_poll_pipe);


@@ -1178,11 +1181,11 @@ static void sighandler(int sig, siginfo_t *siginfo,
        switch (sig) {
        case SIGINT:
                DBG("SIGINT caught");
        switch (sig) {
        case SIGINT:
                DBG("SIGINT caught");

-               stop_threads();
+               notify_main_quit_pipe();

                break;
        case SIGTERM:
                DBG("SIGTERM caught");
                break;
        case SIGTERM:
                DBG("SIGTERM caught");

-               stop_threads();
+               notify_main_quit_pipe();

                break;
        case SIGUSR1:
                CMM_STORE_SHARED(recv_child_signal, 1);
                break;
        case SIGUSR1:
                CMM_STORE_SHARED(recv_child_signal, 1);


@@ -1598,8 +1601,8 @@ int main(int argc, char **argv)
                goto stop_threads;
        }
 
                goto stop_threads;
        }
 

-       /* Create thread quit pipe */
-       if (sessiond_init_thread_quit_pipe()) {
+       /* Create main quit pipe */
+       if (sessiond_init_main_quit_pipe()) {

                retval = -1;
                goto stop_threads;
        }
                retval = -1;
                goto stop_threads;
        }


@@ -1824,7 +1827,6 @@ int main(int argc, char **argv)
        if (!rotation_thread_handle) {
                retval = -1;
                ERR("Failed to create rotation thread shared data");
        if (!rotation_thread_handle) {
                retval = -1;
                ERR("Failed to create rotation thread shared data");

-               stop_threads();

                goto stop_threads;
        }
 
                goto stop_threads;
        }
 


@@ -1917,11 +1919,13 @@ int main(int argc, char **argv)
         * signal that asks threads to teardown).
         */
 
         * signal that asks threads to teardown).
         */
 

-       /* Initiate teardown once activity occurs on the quit pipe. */
-       sessiond_wait_for_quit_pipe(-1);
+       /* Initiate teardown once activity occurs on the main quit pipe. */
+       sessiond_wait_for_main_quit_pipe(-1);

 
 stop_threads:
 
 
 stop_threads:
 

+       DBG("Terminating all threads");
+

        /*
         * Ensure that the client thread is no longer accepting new commands,
         * which could cause new sessions to be created.
        /*
         * Ensure that the client thread is no longer accepting new commands,
         * which could cause new sessions to be created.

diff --git a/src/bin/lttng-sessiond/thread-utils.cpp b/src/bin/lttng-sessiond/thread-utils.cpp
index e28106e785d99aa52a4d5f8d4dc3a40d95524c53..1b8ff0881b68cbb0276037952078dff60e20e60a 100644 (file)
--- a/src/bin/lttng-sessiond/thread-utils.cpp
+++ b/src/bin/lttng-sessiond/thread-utils.cpp
@@ -13,30 +13,31 @@
 #include <pthread.h>
 
 /*
 #include <pthread.h>
 
 /*

- * Quit pipe for all threads. This permits a single cancellation point
- * for all threads when receiving an event on the pipe.
+ * Quit pipe for the main thread. This is used by signal handlers to start the
+ * shutdown sequence of the main thread which will tear down the other threads
+ * in the appropriate order.

  */
  */

-static int thread_quit_pipe[2] = { -1, -1 };
+static int main_quit_pipe[2] = { -1, -1 };

 
 /*
 
 /*

- * Init thread quit pipe.
+ * Init main quit pipe.

  *
  * Return -1 on error or 0 if all pipes are created.
  */
  *
  * Return -1 on error or 0 if all pipes are created.
  */

-static int __init_thread_quit_pipe(int *a_pipe)
+int sessiond_init_main_quit_pipe(void)

 {
        int ret, i;
 
 {
        int ret, i;
 

-       ret = pipe(a_pipe);
+       ret = pipe(main_quit_pipe);

        if (ret < 0) {
        if (ret < 0) {

-               PERROR("thread quit pipe");
+               PERROR("main quit pipe");

                goto error;
        }
 
        for (i = 0; i < 2; i++) {
                goto error;
        }
 
        for (i = 0; i < 2; i++) {

-               ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC);
+               ret = fcntl(main_quit_pipe[i], F_SETFD, FD_CLOEXEC);

                if (ret < 0) {
                if (ret < 0) {

-                       PERROR("fcntl");
+                       PERROR("fcntl main_quit_pipe");

                        goto error;
                }
        }
                        goto error;
                }
        }


@@ -45,25 +46,15 @@ error:
        return ret;
 }
 
        return ret;
 }
 

-int sessiond_init_thread_quit_pipe(void)
-{
-       return __init_thread_quit_pipe(thread_quit_pipe);
-}
-
-int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
-{
-       return (fd == thread_quit_pipe[0] && (events & LPOLLIN));
-}
-

 /*
 /*

- * Wait for a notification on the quit pipe (with a timeout).
+ * Wait for a notification on the main quit pipe (with a timeout).

  *
  * A timeout value of -1U means no timeout.
  *
  * Returns 1 if the caller should quit, 0 if the timeout was reached, and
  * -1 if an error was encountered.
  */
  *
  * A timeout value of -1U means no timeout.
  *
  * Returns 1 if the caller should quit, 0 if the timeout was reached, and
  * -1 if an error was encountered.
  */

-int sessiond_wait_for_quit_pipe(int timeout_ms)
+int sessiond_wait_for_main_quit_pipe(int timeout_ms)

 {
        int ret;
        struct lttng_poll_event events;
 {
        int ret;
        struct lttng_poll_event events;


@@ -74,7 +65,7 @@ int sessiond_wait_for_quit_pipe(int timeout_ms)
                ret = -1;
                goto end;
        }
                ret = -1;
                goto end;
        }

-       ret = lttng_poll_add(&events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
+       ret = lttng_poll_add(&events, main_quit_pipe[0], LPOLLIN | LPOLLERR);

        if (ret < 0) {
                PERROR("Failed to add file descriptor to poll/epoll set");
                ret = -1;
        if (ret < 0) {
                PERROR("Failed to add file descriptor to poll/epoll set");
                ret = -1;


@@ -86,7 +77,7 @@ int sessiond_wait_for_quit_pipe(int timeout_ms)
                ret = 1;
        } else if (ret < 0 && errno != EINTR) {
                /* Unknown error. */
                ret = 1;
        } else if (ret < 0 && errno != EINTR) {
                /* Unknown error. */

-               PERROR("Failed to epoll()/poll() thread quit pipe");
+               PERROR("Failed to epoll()/poll() main quit pipe");

                ret = -1;
        } else {
                /* Timeout reached. */
                ret = -1;
        } else {
                /* Timeout reached. */


@@ -98,19 +89,20 @@ end:
        return ret;
 }
 
        return ret;
 }
 

-int sessiond_notify_quit_pipe(void)
+int sessiond_notify_main_quit_pipe(void)

 {
 {

-       return notify_thread_pipe(thread_quit_pipe[1]);
+       return notify_thread_pipe(main_quit_pipe[1]);

 }
 
 }
 

-void sessiond_close_quit_pipe(void)
+void sessiond_close_main_quit_pipe(void)

 {
 {

-       utils_close_pipe(thread_quit_pipe);
+       utils_close_pipe(main_quit_pipe);

 }
 
 }
 

-static
-int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
-               int *a_pipe)
+/*
+ * Create a poll set with O_CLOEXEC and add the main quit pipe to the set.
+ */
+int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)

 {
        int ret;
 
 {
        int ret;
 


@@ -121,8 +113,8 @@ int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
                goto error;
        }
 
                goto error;
        }
 

-       /* Add quit pipe */
-       ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR);
+       /* Add main quit pipe */
+       ret = lttng_poll_add(events, main_quit_pipe[0], LPOLLIN | LPOLLERR);

        if (ret < 0) {
                goto error;
        }
        if (ret < 0) {
                goto error;
        }


@@ -132,11 +124,3 @@ int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
 error:
        return ret;
 }
 error:
        return ret;
 }

-
-/*
- * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
- */
-int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
-{
-       return __sessiond_set_thread_pollset(events, size, thread_quit_pipe);
-}