From: Peter Zijlstra Date: Sat, 4 Apr 2026 10:22:44 +0000 (+0200) Subject: sched/deadline: Use revised wakeup rule for dl_server X-Git-Tag: v7.0~4^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14a857056466be9d3d907a94e92a704ac1be149b;p=thirdparty%2Fkernel%2Flinux.git sched/deadline: Use revised wakeup rule for dl_server John noted that commit 115135422562 ("sched/deadline: Fix 'stuck' dl_server") unfixed the issue from commit a3a70caf7906 ("sched/deadline: Fix dl_server behaviour"). The issue in commit 115135422562 was for wakeups of the server after the deadline; in which case you *have* to start a new period. The case for a3a70caf7906 is wakeups before the deadline. Now, because the server is effectively running a least-laxity policy, it means that any wakeup during the runnable phase means dl_entity_overflow() will be true. This means we need to adjust the runtime to allow it to still run until the existing deadline expires. Use the revised wakeup rule for dl_defer entities. Fixes: 115135422562 ("sched/deadline: Fix 'stuck' dl_server") Reported-by: John Stultz Signed-off-by: Peter Zijlstra (Intel) Acked-by: Juri Lelli Tested-by: John Stultz Link: https://patch.msgid.link/20260404102244.GB22575@noisy.programming.kicks-ass.net --- diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index d08b004293234..674de6a48551b 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1027,7 +1027,7 @@ static void update_dl_entity(struct sched_dl_entity *dl_se) if (dl_time_before(dl_se->deadline, rq_clock(rq)) || dl_entity_overflow(dl_se, rq_clock(rq))) { - if (unlikely(!dl_is_implicit(dl_se) && + if (unlikely((!dl_is_implicit(dl_se) || dl_se->dl_defer) && !dl_time_before(dl_se->deadline, rq_clock(rq)) && !is_dl_boosted(dl_se))) { update_dl_revised_wakeup(dl_se, rq);