On 08/29/2017 12:05 AM, Martin Wilck wrote:
> DAEMON_RUNNING is only used by checkerloop to indicate that
> path checkers are running. checkerloop switches back and forth
> between DAEMON_IDLE and DAEMON_RUNNING in every iteration, i.e.
> it performs two status changes per second on an idle system.
> The repeated sd_notify() calls cause a lot of traffic on dbus as
> systemd forwards these messages on the system bus. This can be
> seen with systemd.log_level=debug. Better skip these notifications
> that don't provide useful information to the user, who is very
> unlikely to catch the daemon in "running" state anyway.
>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> multipathd/main.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 4be2c579..b5e2b00d 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -161,15 +161,27 @@ sd_notify_status(void)
> case DAEMON_CONFIGURE:
> return "STATUS=configure";
> case DAEMON_IDLE:
> - return "STATUS=idle";
> case DAEMON_RUNNING:
> - return "STATUS=running";
> + return "STATUS=up";
> case DAEMON_SHUTDOWN:
> return "STATUS=shutdown";
> }
> return NULL;
> }
>
> +static void do_sd_notify(enum daemon_status old_state)
> +{
> + /*
> + * Checkerloop switches back and forth between idle and running state.
> + * No need to tell systemd each time.
> + * These notifications cause a lot of overhead on dbus.
> + */
> + if ((running_state == DAEMON_IDLE || running_state == DAEMON_RUNNING) &&
> + (old_state == DAEMON_IDLE || old_state == DAEMON_RUNNING))
> + return;
> + sd_notify(0, sd_notify_status());
> +}
> +
> static void config_cleanup(void *arg)
> {
> pthread_mutex_unlock(&config_lock);
> @@ -179,10 +191,12 @@ void post_config_state(enum daemon_status state)
> {
> pthread_mutex_lock(&config_lock);
> if (state != running_state) {
> + enum daemon_status old_state = running_state;
> +
> running_state = state;
> pthread_cond_broadcast(&config_cond);
> #ifdef USE_SYSTEMD
> - sd_notify(0, sd_notify_status());
> + do_sd_notify(old_state);
> #endif
> }
> pthread_mutex_unlock(&config_lock);
> @@ -195,6 +209,8 @@ int set_config_state(enum daemon_status state)
> pthread_cleanup_push(config_cleanup, NULL);
> pthread_mutex_lock(&config_lock);
> if (running_state != state) {
> + enum daemon_status old_state = running_state;
> +
> if (running_state != DAEMON_IDLE) {
> struct timespec ts;
>
> @@ -207,7 +223,7 @@ int set_config_state(enum daemon_status state)
> running_state = state;
> pthread_cond_broadcast(&config_cond);
> #ifdef USE_SYSTEMD
> - sd_notify(0, sd_notify_status());
> + do_sd_notify(old_state);
> #endif
> }
> }
>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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