SoW-2020-0002: Trace Hit Counters

[lttng-tools.git] / src / bin / lttng-sessiond / main.c

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index a344cd4769dbce11493828e2c1f6bbb367f255c3..6e4950e54887a9767bad655653335a8ad15b0304 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -49,9 +49,9 @@
 #include "consumer.h"
 #include "context.h"
 #include "event.h"
+#include "event-notifier-error-accounting.h"
 #include "kernel.h"
 #include "kernel-consumer.h"
-#include "shm.h"
 #include "lttng-ust-ctl.h"
 #include "ust-consumer.h"
 #include "utils.h"
@@ -74,6 +74,7 @@
 #include "register.h"
 #include "manage-apps.h"
 #include "manage-kernel.h"
+#include "modprobe.h"
 
 static const char *help_msg =
 #ifdef LTTNG_EMBED_HELP
@@ -83,6 +84,8 @@ NULL
 #endif
 ;
 
+#define EVENT_NOTIFIER_ERROR_COUNTER_NUMBER_OF_BUCKET_MAX 65535
+
 const char *progname;
 static int lockfile_fd = -1;
 static int opt_print_version;
@@ -120,6 +123,7 @@ static const struct option long_options[] = {
        { "load", required_argument, 0, 'l' },
        { "kmod-probes", required_argument, 0, '\0' },
        { "extra-kmod-probes", required_argument, 0, '\0' },
+       { "event-notifier-error-number-of-bucket", required_argument, 0, '\0' },
        { NULL, 0, 0, 0 }
 };
 
@@ -697,6 +701,23 @@ static int set_option(int opt, const char *arg, const char *optname)
                                ret = -ENOMEM;
                        }
                }
+       } else if (string_match(optname, "event-notifier-error-number-of-bucket")) {
+               unsigned long v;
+
+               errno = 0;
+               v = strtoul(arg, NULL, 0);
+               if (errno != 0 || !isdigit(arg[0])) {
+                       ERR("Wrong value in --event-notifier-error-number-of-bucket parameter: %s", arg);
+                       return -1;
+               }
+               if (v == 0 || v >= EVENT_NOTIFIER_ERROR_COUNTER_NUMBER_OF_BUCKET_MAX) {
+                       ERR("Value out of range for --event-notifier-error-number-of-bucket parameter: %s", arg);
+                       return -1;
+               }
+               config.event_notifier_error_counter_bucket = (int) v;
+               DBG3("Number of event notifier error counter set to non default: %i",
+                               config.event_notifier_error_counter_bucket);
+               goto end;
        } else if (string_match(optname, "config") || opt == 'f') {
                /* This is handled in set_options() thus silent skip. */
                goto end;
@@ -1243,6 +1264,7 @@ static void destroy_all_sessions_and_wait(void)
                        goto unlock_session;
                }
                (void) cmd_stop_trace(session);
+
                (void) cmd_destroy_session(session, notification_thread_handle,
                                NULL);
        unlock_session:
@@ -1589,6 +1611,8 @@ int main(int argc, char **argv)
                goto stop_threads;
        }
 
+       event_notifier_error_accounting_init(config.event_notifier_error_counter_bucket);
+
        /*
         * Initialize agent app hash table. We allocate the hash table here
         * since cleanup() can get called after this point.
@@ -1826,6 +1850,7 @@ int main(int argc, char **argv)
        sessiond_wait_for_quit_pipe(-1);
 
 stop_threads:
+
        /*
         * Ensure that the client thread is no longer accepting new commands,
         * which could cause new sessions to be created.
@@ -1864,7 +1889,7 @@ stop_threads:
        sessiond_cleanup();
 
        /*
-        * Wait for all pending call_rcu work to complete tearing shutting down
+        * Wait for all pending call_rcu work to complete before shutting down
         * the notification thread. This call_rcu work includes shutting down
         * UST apps and event notifier pipes.
         */
@@ -1875,6 +1900,27 @@ stop_threads:
                lttng_thread_put(notification_thread);
        }
 
+       /*
+        * Error accounting teardown has to be done after the teardown of all
+        * event notifier pipes to ensure that no tracer may try to use the
+        * error accounting facilities.
+        */
+       event_notifier_error_accounting_fini();
+
+       /*
+        * Unloading the kernel modules needs to be done after all kernel
+        * ressources have been released. In our case, this includes the
+        * notification fd, the event notifier group fd, error accounting fd,
+        * all event and event notifier fds, etc.
+        *
+        * In short, at this point, we need to have called close() on all fds
+        * received from the kernel tracer.
+        */
+       if (is_root && !config.no_kernel) {
+               DBG("Unloading kernel modules");
+               modprobe_remove_lttng_all();
+       }
+
        /*
         * Ensure all prior call_rcu are done. call_rcu callbacks may push
         * hash tables to the ht_cleanup thread. Therefore, we ensure that