daandemeyer / rpms / systemd

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From 4ce10f8e41a85a56ad9b805442eb1149ece7c82a Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Michal=20Sekleta=CC=81r?= <msekleta@redhat.com>
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Date: Fri, 23 Oct 2020 18:29:27 +0200
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Subject: [PATCH] sd-event: split out helper functions for reshuffling prioqs
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We typically don't just reshuffle a single prioq at once, but always
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two. Let's add two helper functions that do this, and reuse them
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everywhere.
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(Note that this drops one minor optimization:
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sd_event_source_set_time_accuracy() previously only reshuffled the
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"latest" prioq, since changing the accuracy has no effect on the
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earliest time of an event source, just the latest time an event source
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can run. This optimization is removed to simplify things, given that
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it's not really worth the effort as prioq_reshuffle() on properly
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ordered prioqs has practically zero cost O(1)).
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(Slightly generalized, commented and split out of #17284 by Lennart)
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(cherry picked from commit e1951c16a8fbe5b0b9ecc08f4f835a806059d28f)
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Related: #1819868
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---
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 src/libsystemd/sd-event/sd-event.c | 96 ++++++++++++------------------
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 1 file changed, 38 insertions(+), 58 deletions(-)
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diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
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index 0d3bf5cbb6..47f99eb096 100644
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--- a/src/libsystemd/sd-event/sd-event.c
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+++ b/src/libsystemd/sd-event/sd-event.c
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@@ -889,6 +889,33 @@ static void event_gc_signal_data(sd_event *e, const int64_t *priority, int sig)
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                 event_unmask_signal_data(e, d, sig);
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 }
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+static void event_source_pp_prioq_reshuffle(sd_event_source *s) {
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+        assert(s);
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+
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+        /* Reshuffles the pending + prepare prioqs. Called whenever the dispatch order changes, i.e. when
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+         * they are enabled/disabled or marked pending and such. */
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+
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+        if (s->pending)
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+                prioq_reshuffle(s->event->pending, s, &s->pending_index);
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+
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+        if (s->prepare)
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+                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
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+}
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+
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+static void event_source_time_prioq_reshuffle(sd_event_source *s) {
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+        struct clock_data *d;
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+
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+        assert(s);
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+        assert(EVENT_SOURCE_IS_TIME(s->type));
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+
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+        /* Called whenever the event source's timer ordering properties changed, i.e. time, accuracy,
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+         * pending, enable state. Makes sure the two prioq's are ordered properly again. */
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+        assert_se(d = event_get_clock_data(s->event, s->type));
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+        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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+        prioq_reshuffle(d->latest, s, &s->time.latest_index);
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+        d->needs_rearm = true;
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+}
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+
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 static void source_disconnect(sd_event_source *s) {
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         sd_event *event;
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@@ -1052,16 +1079,8 @@ static int source_set_pending(sd_event_source *s, bool b) {
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         } else
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                 assert_se(prioq_remove(s->event->pending, s, &s->pending_index));
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-        if (EVENT_SOURCE_IS_TIME(s->type)) {
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-                struct clock_data *d;
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-
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-                d = event_get_clock_data(s->event, s->type);
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-                assert(d);
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-
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-                prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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-                prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-                d->needs_rearm = true;
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-        }
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+        if (EVENT_SOURCE_IS_TIME(s->type))
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+                event_source_time_prioq_reshuffle(s);
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         if (s->type == SOURCE_SIGNAL && !b) {
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                 struct signal_data *d;
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@@ -2215,11 +2234,7 @@ _public_ int sd_event_source_set_priority(sd_event_source *s, int64_t priority)
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         } else
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                 s->priority = priority;
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-        if (s->pending)
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-                prioq_reshuffle(s->event->pending, s, &s->pending_index);
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-
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-        if (s->prepare)
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-                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
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+        event_source_pp_prioq_reshuffle(s);
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         if (s->type == SOURCE_EXIT)
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                 prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
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@@ -2280,18 +2295,10 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
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                 case SOURCE_TIME_BOOTTIME:
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                 case SOURCE_TIME_MONOTONIC:
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                 case SOURCE_TIME_REALTIME_ALARM:
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-                case SOURCE_TIME_BOOTTIME_ALARM: {
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-                        struct clock_data *d;
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-
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+                case SOURCE_TIME_BOOTTIME_ALARM:
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                         s->enabled = m;
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-                        d = event_get_clock_data(s->event, s->type);
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-                        assert(d);
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-
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-                        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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-                        prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-                        d->needs_rearm = true;
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+                        event_source_time_prioq_reshuffle(s);
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                         break;
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-                }
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                 case SOURCE_SIGNAL:
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                         s->enabled = m;
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@@ -2346,18 +2353,10 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
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                 case SOURCE_TIME_BOOTTIME:
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                 case SOURCE_TIME_MONOTONIC:
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                 case SOURCE_TIME_REALTIME_ALARM:
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-                case SOURCE_TIME_BOOTTIME_ALARM: {
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-                        struct clock_data *d;
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-
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+                case SOURCE_TIME_BOOTTIME_ALARM:
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                         s->enabled = m;
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-                        d = event_get_clock_data(s->event, s->type);
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-                        assert(d);
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-
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-                        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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-                        prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-                        d->needs_rearm = true;
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+                        event_source_time_prioq_reshuffle(s);
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                         break;
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-                }
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                 case SOURCE_SIGNAL:
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@@ -2405,11 +2404,7 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
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                 }
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         }
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-        if (s->pending)
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-                prioq_reshuffle(s->event->pending, s, &s->pending_index);
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-
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-        if (s->prepare)
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-                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
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+        event_source_pp_prioq_reshuffle(s);
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         return 0;
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 }
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@@ -2425,7 +2420,6 @@ _public_ int sd_event_source_get_time(sd_event_source *s, uint64_t *usec) {
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 }
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 _public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) {
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-        struct clock_data *d;
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         int r;
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         assert_return(s, -EINVAL);
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@@ -2439,13 +2433,7 @@ _public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) {
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         s->time.next = usec;
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-        d = event_get_clock_data(s->event, s->type);
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-        assert(d);
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-
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-        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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-        prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-        d->needs_rearm = true;
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-
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+        event_source_time_prioq_reshuffle(s);
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         return 0;
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 }
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@@ -2460,7 +2448,6 @@ _public_ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *use
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 }
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 _public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec) {
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-        struct clock_data *d;
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         int r;
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         assert_return(s, -EINVAL);
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@@ -2478,12 +2465,7 @@ _public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec
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         s->time.accuracy = usec;
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-        d = event_get_clock_data(s->event, s->type);
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-        assert(d);
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-
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-        prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-        d->needs_rearm = true;
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-
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+        event_source_time_prioq_reshuffle(s);
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         return 0;
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 }
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@@ -2773,9 +2755,7 @@ static int process_timer(
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                 if (r < 0)
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                         return r;
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-                prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
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-                prioq_reshuffle(d->latest, s, &s->time.latest_index);
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-                d->needs_rearm = true;
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+                event_source_time_prioq_reshuffle(s);
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         }
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         return 0;