From 93de7820843c175f4c9661dbfcb312e8ee09fbd3 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Tue, 8 Jun 2021 00:07:51 -0700 Subject: [PATCH] sd-event: change ordering of pending/ratelimited events Instead of ordering non-pending before pending we should order "non-pending OR ratelimited" before "pending AND not-ratelimited". This fixes a bug where ratelimited events were ordered at the end of the priority queue and could be stuck there for an indeterminate amount of time. (cherry picked from commit 81107b8419c39f726fd2805517a5b9faab204e59) Related: #1984406 --- src/libsystemd/sd-event/sd-event.c | 48 +++++++++++++----------------- 1 file changed, 20 insertions(+), 28 deletions(-) diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c index be912d94e3..3e77f4e810 100644 --- a/src/libsystemd/sd-event/sd-event.c +++ b/src/libsystemd/sd-event/sd-event.c @@ -427,25 +427,6 @@ static usec_t time_event_source_next(const sd_event_source *s) { return USEC_INFINITY; } -static int earliest_time_prioq_compare(const void *a, const void *b) { - const sd_event_source *x = a, *y = b; - - /* Enabled ones first */ - if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF) - return -1; - if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF) - return 1; - - /* Move the pending ones to the end */ - if (!x->pending && y->pending) - return -1; - if (x->pending && !y->pending) - return 1; - - /* Order by time */ - return CMP(time_event_source_next(x), time_event_source_next(y)); -} - static usec_t time_event_source_latest(const sd_event_source *s) { assert(s); @@ -464,7 +445,15 @@ static usec_t time_event_source_latest(const sd_event_source *s) { return USEC_INFINITY; } -static int latest_time_prioq_compare(const void *a, const void *b) { +static bool event_source_timer_candidate(const sd_event_source *s) { + assert(s); + + /* Returns true for event sources that either are not pending yet (i.e. where it's worth to mark them pending) + * or which are currently ratelimited (i.e. where it's worth leaving the ratelimited state) */ + return !s->pending || s->ratelimited; +} + +static int time_prioq_compare(const void *a, const void *b, usec_t (*time_func)(const sd_event_source *s)) { const sd_event_source *x = a, *y = b; /* Enabled ones first */ @@ -473,19 +462,22 @@ static int latest_time_prioq_compare(const void *a, const void *b) { if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF) return 1; - /* Move the pending ones to the end */ - if (!x->pending && y->pending) + /* Order "non-pending OR ratelimited" before "pending AND not-ratelimited" */ + if (event_source_timer_candidate(x) && !event_source_timer_candidate(y)) return -1; - if (x->pending && !y->pending) + if (!event_source_timer_candidate(x) && event_source_timer_candidate(y)) return 1; /* Order by time */ - if (time_event_source_latest(x) < time_event_source_latest(y)) - return -1; - if (time_event_source_latest(x) > time_event_source_latest(y)) - return 1; + return CMP(time_func(x), time_func(y)); +} - return 0; +static int earliest_time_prioq_compare(const void *a, const void *b) { + return time_prioq_compare(a, b, time_event_source_next); +} + +static int latest_time_prioq_compare(const void *a, const void *b) { + return time_prioq_compare(a, b, time_event_source_latest); } static int exit_prioq_compare(const void *a, const void *b) {