From: Juri Lelli Date: Fri, 27 Jun 2025 11:51:15 +0000 (+0200) Subject: sched/deadline: Reset extra_bw to max_bw when clearing root domains X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fcc9276c4d331cd1fe9319d793e80b02e09727f5;p=thirdparty%2Fkernel%2Fstable.git sched/deadline: Reset extra_bw to max_bw when clearing root domains dl_clear_root_domain() doesn't take into account the fact that per-rq extra_bw variables retain values computed before root domain changes, resulting in broken accounting. Fix it by resetting extra_bw to max_bw before restoring back dl-servers contributions. Fixes: 2ff899e351643 ("sched/deadline: Rebuild root domain accounting after every update") Reported-by: Marcel Ziswiler Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Tested-by: Marcel Ziswiler # nuc & rock5b Link: https://lore.kernel.org/r/20250627115118.438797-3-juri.lelli@redhat.com --- diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 0d25553f2c17..0abffe3860e3 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2924,7 +2924,14 @@ void dl_clear_root_domain(struct root_domain *rd) int i; guard(raw_spinlock_irqsave)(&rd->dl_bw.lock); + + /* + * Reset total_bw to zero and extra_bw to max_bw so that next + * loop will add dl-servers contributions back properly, + */ rd->dl_bw.total_bw = 0; + for_each_cpu(i, rd->span) + cpu_rq(i)->dl.extra_bw = cpu_rq(i)->dl.max_bw; /* * dl_servers are not tasks. Since dl_add_task_root_domain ignores