Commit ed636de4 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Merge remote-tracking branch 'github/ticket25951'

parents be9f0e5f 77b7eb27

changes/ticket25951

0 → 100644
+9 −0
Original line number Diff line number Diff line 
  o Minor features (mainloop):

    - Move responsibility for

      flushing log callbacks

      from a once-per-second callback to a callback that is only scheduled as

      needed.  Once enough items are removed from our once-per-second

      callback, we can eliminate it entirely to conserve CPU when idle.

      Closes ticket

      25951.

src/common/log.c

+25 −0
Original line number Diff line number Diff line
@@ -170,6 +170,9 @@ typedef struct pending_log_message_t { 
/** Log messages waiting to be replayed onto callback-based logs */

static smartlist_t *pending_cb_messages = NULL;



/** Callback to invoke when pending_cb_messages becomes nonempty. */

static pending_callback_callback pending_cb_cb = NULL;



/** Log messages waiting to be replayed once the logging system is initialized.

 */

static smartlist_t *pending_startup_messages = NULL;
@@ -538,6 +541,9 @@ logfile_deliver(logfile_t *lf, const char *buf, size_t msg_len, 
        smartlist_add(pending_cb_messages,

            pending_log_message_new(severity,domain,NULL,msg_after_prefix));

        *callbacks_deferred = 1;

        if (smartlist_len(pending_cb_messages) == 1 && pending_cb_cb) {

          pending_cb_cb();

        }

      }

    } else {

      lf->callback(severity, domain, msg_after_prefix);
@@ -825,6 +831,7 @@ logs_free_all(void) 
  logfiles = NULL;

  messages = pending_cb_messages;

  pending_cb_messages = NULL;

  pending_cb_cb = NULL;

  messages2 = pending_startup_messages;

  pending_startup_messages = NULL;

  UNLOCK_LOGS();
@@ -987,6 +994,24 @@ add_temp_log(int min_severity) 
  UNLOCK_LOGS();

}



/**

 * Register "cb" as the callback to call when there are new pending log

 * callbacks to be flushed with flush_pending_log_callbacks().

 *

 * Note that this callback, if present, can be invoked from any thread.

 *

 * This callback must not log.

 *

 * It is intentional that this function contains the name "callback" twice: it

 * sets a "callback" to be called on the condition that there is a "pending

 * callback".

 **/

void

logs_set_pending_callback_callback(pending_callback_callback cb)

{

  pending_cb_cb = cb;

}



/**

 * Add a log handler to send messages in <b>severity</b>

 * to the function <b>cb</b>.

src/common/torlog.h

+2 −0
Original line number Diff line number Diff line
@@ -154,6 +154,8 @@ int add_android_log(const log_severity_list_t *severity, 
                    const char *android_identity_tag);

#endif // HAVE_ANDROID_LOG_H.

int add_callback_log(const log_severity_list_t *severity, log_callback cb);

typedef void (*pending_callback_callback)(void);

void logs_set_pending_callback_callback(pending_callback_callback cb);

void logs_set_domain_logging(int enabled);

int get_min_log_level(void);

void switch_logs_debug(void);

src/or/config.c

+1 −0
Original line number Diff line number Diff line
@@ -1552,6 +1552,7 @@ options_act_reversible(const or_options_t *old_options, char **msg) 
      tor_malloc_zero(sizeof(log_severity_list_t));

    close_temp_logs();

    add_callback_log(severity, control_event_logmsg);

    logs_set_pending_callback_callback(control_event_logmsg_pending);

    control_adjust_event_log_severity();

    tor_free(severity);

    tor_log_update_sigsafe_err_fds();

src/or/control.c

+21 −1
Original line number Diff line number Diff line
@@ -803,6 +803,9 @@ queued_event_free_(queued_event_t *ev) 
static void

queued_events_flush_all(int force)

{

  /* Make sure that we get all the pending log events, if there are any. */

  flush_pending_log_callbacks();



  if (PREDICT_UNLIKELY(queued_control_events == NULL)) {

    return;

  }
@@ -6186,7 +6189,7 @@ control_event_logmsg(int severity, uint32_t domain, const char *msg) 
  int event;



  /* Don't even think of trying to add stuff to a buffer from a cpuworker

   * thread. */

   * thread. (See #25987 for plan to fix.) */

  if (! in_main_thread())

    return;
@@ -6232,6 +6235,23 @@ control_event_logmsg(int severity, uint32_t domain, const char *msg) 
  }

}



/**

 * Logging callback: called when there is a queued pending log callback.

 */

void

control_event_logmsg_pending(void)

{

  if (! in_main_thread()) {

    /* We can't handle this case yet, since we're using a

     * mainloop_event_t to invoke queued_events_flush_all.  We ought to

     * use a different mechanism instead: see #25987.

     **/

    return;

  }

  tor_assert(flush_queued_events_event);

  mainloop_event_activate(flush_queued_events_event);

}



/** Called whenever we receive new router descriptors: tell any

 * interested control connections.  <b>routers</b> is a list of

 * routerinfo_t's.