From ea762f1c0206c99d2ba4d3cba41cadf70311a3cc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michal=20Sekleta=CC=81r?= Date: Fri, 23 Oct 2020 18:29:27 +0200 Subject: [PATCH 03/20] sd-event: split out helper functions for reshuffling prioqs We typically don't just reshuffle a single prioq at once, but always two. Let's add two helper functions that do this, and reuse them everywhere. (Note that this drops one minor optimization: sd_event_source_set_time_accuracy() previously only reshuffled the "latest" prioq, since changing the accuracy has no effect on the earliest time of an event source, just the latest time an event source can run. This optimization is removed to simplify things, given that it's not really worth the effort as prioq_reshuffle() on properly ordered prioqs has practically zero cost O(1)). (Slightly generalized, commented and split out of #17284 by Lennart) (cherry picked from commit e1951c16a8fbe5b0b9ecc08f4f835a806059d28f) Related: #1819868 [commit 4ce10f8e41a85a56ad9b805442eb1149ece7c82a from https://github.com/systemd-rhel/rhel-8/] Signed-off-by: Li Zhou --- src/libsystemd/sd-event/sd-event.c | 96 ++++++++++++------------------ 1 file changed, 38 insertions(+), 58 deletions(-) diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c index 26ef3ea..eb3182f 100644 --- a/src/libsystemd/sd-event/sd-event.c +++ b/src/libsystemd/sd-event/sd-event.c @@ -784,6 +784,33 @@ static void event_gc_signal_data(sd_event *e, const int64_t *priority, int sig) event_unmask_signal_data(e, d, sig); } +static void event_source_pp_prioq_reshuffle(sd_event_source *s) { + assert(s); + + /* Reshuffles the pending + prepare prioqs. Called whenever the dispatch order changes, i.e. when + * they are enabled/disabled or marked pending and such. */ + + if (s->pending) + prioq_reshuffle(s->event->pending, s, &s->pending_index); + + if (s->prepare) + prioq_reshuffle(s->event->prepare, s, &s->prepare_index); +} + +static void event_source_time_prioq_reshuffle(sd_event_source *s) { + struct clock_data *d; + + assert(s); + assert(EVENT_SOURCE_IS_TIME(s->type)); + + /* Called whenever the event source's timer ordering properties changed, i.e. time, accuracy, + * pending, enable state. Makes sure the two prioq's are ordered properly again. */ + assert_se(d = event_get_clock_data(s->event, s->type)); + prioq_reshuffle(d->earliest, s, &s->time.earliest_index); + prioq_reshuffle(d->latest, s, &s->time.latest_index); + d->needs_rearm = true; +} + static void source_disconnect(sd_event_source *s) { sd_event *event; @@ -905,16 +932,8 @@ static int source_set_pending(sd_event_source *s, bool b) { } else assert_se(prioq_remove(s->event->pending, s, &s->pending_index)); - if (EVENT_SOURCE_IS_TIME(s->type)) { - struct clock_data *d; - - d = event_get_clock_data(s->event, s->type); - assert(d); - - prioq_reshuffle(d->earliest, s, &s->time.earliest_index); - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; - } + if (EVENT_SOURCE_IS_TIME(s->type)) + event_source_time_prioq_reshuffle(s); if (s->type == SOURCE_SIGNAL && !b) { struct signal_data *d; @@ -1570,11 +1589,7 @@ _public_ int sd_event_source_set_priority(sd_event_source *s, int64_t priority) } else s->priority = priority; - if (s->pending) - prioq_reshuffle(s->event->pending, s, &s->pending_index); - - if (s->prepare) - prioq_reshuffle(s->event->prepare, s, &s->prepare_index); + event_source_pp_prioq_reshuffle(s); if (s->type == SOURCE_EXIT) prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index); @@ -1622,18 +1637,10 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) { case SOURCE_TIME_BOOTTIME: case SOURCE_TIME_MONOTONIC: case SOURCE_TIME_REALTIME_ALARM: - case SOURCE_TIME_BOOTTIME_ALARM: { - struct clock_data *d; - + case SOURCE_TIME_BOOTTIME_ALARM: s->enabled = m; - d = event_get_clock_data(s->event, s->type); - assert(d); - - prioq_reshuffle(d->earliest, s, &s->time.earliest_index); - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; + event_source_time_prioq_reshuffle(s); break; - } case SOURCE_SIGNAL: s->enabled = m; @@ -1679,18 +1686,10 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) { case SOURCE_TIME_BOOTTIME: case SOURCE_TIME_MONOTONIC: case SOURCE_TIME_REALTIME_ALARM: - case SOURCE_TIME_BOOTTIME_ALARM: { - struct clock_data *d; - + case SOURCE_TIME_BOOTTIME_ALARM: s->enabled = m; - d = event_get_clock_data(s->event, s->type); - assert(d); - - prioq_reshuffle(d->earliest, s, &s->time.earliest_index); - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; + event_source_time_prioq_reshuffle(s); break; - } case SOURCE_SIGNAL: @@ -1737,11 +1736,7 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) { } } - if (s->pending) - prioq_reshuffle(s->event->pending, s, &s->pending_index); - - if (s->prepare) - prioq_reshuffle(s->event->prepare, s, &s->prepare_index); + event_source_pp_prioq_reshuffle(s); return 0; } @@ -1757,7 +1752,6 @@ _public_ int sd_event_source_get_time(sd_event_source *s, uint64_t *usec) { } _public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) { - struct clock_data *d; assert_return(s, -EINVAL); assert_return(usec != (uint64_t) -1, -EINVAL); @@ -1769,13 +1763,7 @@ _public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) { source_set_pending(s, false); - d = event_get_clock_data(s->event, s->type); - assert(d); - - prioq_reshuffle(d->earliest, s, &s->time.earliest_index); - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; - + event_source_time_prioq_reshuffle(s); return 0; } @@ -1790,7 +1778,6 @@ _public_ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *use } _public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec) { - struct clock_data *d; assert_return(s, -EINVAL); assert_return(usec != (uint64_t) -1, -EINVAL); @@ -1805,12 +1792,7 @@ _public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec source_set_pending(s, false); - d = event_get_clock_data(s->event, s->type); - assert(d); - - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; - + event_source_time_prioq_reshuffle(s); return 0; } @@ -2088,9 +2070,7 @@ static int process_timer( if (r < 0) return r; - prioq_reshuffle(d->earliest, s, &s->time.earliest_index); - prioq_reshuffle(d->latest, s, &s->time.latest_index); - d->needs_rearm = true; + event_source_time_prioq_reshuffle(s); } return 0; -- 2.17.1