Date: Tue, 21 Apr 2026 15:46:00 +0000 From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Cc: Jake Freeland <jfree@FreeBSD.org> Subject: git: f37c6e3a133e - releng/14.3 - timerfd: Fix interval callout scheduling Message-ID: <69e79bb8.347c9.365d6235@gitrepo.freebsd.org>
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The branch releng/14.3 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=f37c6e3a133e37c742b23ba646b710492603bc51 commit f37c6e3a133e37c742b23ba646b710492603bc51 Author: Jake Freeland <jfree@FreeBSD.org> AuthorDate: 2026-03-20 06:33:03 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2026-04-21 15:45:50 +0000 timerfd: Fix interval callout scheduling When a timerfd interval callout misses its scheduled activation time, a differential is calculated based on the actual activation time and the scheduled activation time. This differential is divided by the timerfd's interval time and the quotient is added to the timerfd's counter. Before this change, the next callout was scheduled to activate at: scheduled activation time + timerfd interval. This change fixes the scheduling of the next callout to activate at: actual activation time + timerfd interval - remainder. Security: FreeBSD-26:06.timerfd Approved by: so Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D55790 MFC after: 2 weeks (cherry picked from commit 85c0f1a87da1fd1eb3e646e86f70e630c48da91a) (cherry picked from commit 3c00f603a2801fd780666f9e94a26f264a887c90) --- sys/kern/sys_timerfd.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/sys/kern/sys_timerfd.c b/sys/kern/sys_timerfd.c index ab7e048a2ab1..59c554f2dba8 100644 --- a/sys/kern/sys_timerfd.c +++ b/sys/kern/sys_timerfd.c @@ -394,23 +394,25 @@ static void timerfd_expire(void *arg) { struct timerfd *tfd = (struct timerfd *)arg; - struct timespec uptime; + sbintime_t exp, interval, now, next, diff; ++tfd->tfd_count; tfd->tfd_expired = true; if (timespecisset(&tfd->tfd_time.it_interval)) { + exp = tstosbt(tfd->tfd_time.it_value); + interval = tstosbt(tfd->tfd_time.it_interval); + now = sbinuptime(); + next = now + interval; + /* Count missed events. */ - nanouptime(&uptime); - if (timespeccmp(&uptime, &tfd->tfd_time.it_value, >)) { - timespecsub(&uptime, &tfd->tfd_time.it_value, &uptime); - tfd->tfd_count += tstosbt(uptime) / - tstosbt(tfd->tfd_time.it_interval); + if (now > exp) { + diff = now - exp; + tfd->tfd_count += diff / interval; + next -= diff % interval; } - timespecadd(&tfd->tfd_time.it_value, - &tfd->tfd_time.it_interval, &tfd->tfd_time.it_value); - callout_schedule_sbt(&tfd->tfd_callout, - tstosbt(tfd->tfd_time.it_value), - 0, C_ABSOLUTE); + + callout_schedule_sbt(&tfd->tfd_callout, next, 0, C_ABSOLUTE); + tfd->tfd_time.it_value = sbttots(next); } else { /* Single shot timer. */ callout_deactivate(&tfd->tfd_callout);home | help
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