SoW-2020-0003: Trace Hit Counters

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

diff --git a/src/bin/lttng-sessiond/notification-thread.c b/src/bin/lttng-sessiond/notification-thread.c
index 1ba724337b67ee69a1856087a5c8b65c45a32cd8..b91dc5798df67140a43958f5cf87e128bd60acc7 100644 (file)
--- a/src/bin/lttng-sessiond/notification-thread.c
+++ b/src/bin/lttng-sessiond/notification-thread.c
@@ -27,6 +27,7 @@
 #include "lttng-sessiond.h"
 #include "health-sessiond.h"
 #include "thread.h"
+#include "testpoint.h"
 
 #include "kernel.h"
 #include <common/kernel-ctl/kernel-ctl.h>
@@ -35,6 +36,8 @@
 #include <urcu/list.h>
 #include <urcu/rculfhash.h>
 
+
+int notifier_consumption_paused;
 /*
  * Destroy the thread data previously created by the init function.
  */
@@ -482,6 +485,7 @@ int init_thread_state(struct notification_thread_handle *handle,
        if (!state->channels_ht) {
                goto error;
        }
+
        state->sessions_ht = cds_lfht_new(DEFAULT_HT_SIZE,
                        1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
        if (!state->sessions_ht) {
@@ -510,6 +514,9 @@ int init_thread_state(struct notification_thread_handle *handle,
        if (!state->executor) {
                goto error;
        }
+
+       state->restart_poll = false;
+
        mark_thread_as_ready(handle);
 end:
        return 0;
@@ -571,6 +578,17 @@ static int handle_event_notification_pipe(int event_source_fd,
                goto end;
        }
 
+       if (testpoint(sessiond_handle_notifier_event_pipe)) {
+               ret = 0;
+               goto end;
+       }
+
+       if (caa_unlikely(notifier_consumption_paused)) {
+               DBG("Event notifier notification consumption paused, sleeping...");
+               sleep(1);
+               goto end;
+       }
+
        ret = handle_notification_thread_event_notification(
                        state, event_source_fd, domain);
        if (ret) {
@@ -579,6 +597,7 @@ static int handle_event_notification_pipe(int event_source_fd,
                ret = -1;
                goto end;
        }
+
 end:
        return ret;
 }
@@ -637,6 +656,10 @@ void *thread_notification(void *data)
                goto end;
        }
 
+       if (testpoint(sessiond_thread_notification)) {
+               goto end;
+       }
+
        while (true) {
                int fd_count, i;
 
@@ -656,6 +679,12 @@ void *thread_notification(void *data)
                        goto error;
                }
 
+               /*
+                * Reset restart_poll flag so that calls below might turn it
+                * on.
+                */
+               state.restart_poll = false;
+
                fd_count = ret;
                for (i = 0; i < fd_count; i++) {
                        int fd = LTTNG_POLL_GETFD(&state.events, i);
@@ -733,6 +762,15 @@ void *thread_notification(void *data)
                                        }
                                }
                        }
+
+                       /*
+                        * Calls above might have changed the state of the
+                        * FDs in `state.events`. Call _poll_wait() again to
+                        * ensure we have a consistent state.
+                        */
+                       if (state.restart_poll) {
+                               break;
+                       }
                }
        }
 exit: