From 68ec89d0e99156803bdea3c986c0198624e40ea2 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Mon, 26 Jan 2026 10:59:01 +0100 Subject: [PATCH] sched/debug: Stop and start server based on if it was active Currently the DL server interface for applying parameters checks CFS-internals to identify if the server is active. This is error-prone and makes it difficult when adding new servers in the future. Fix it, by using dl_server_active() which is also used by the DL server code to determine if the DL server was started. Signed-off-by: Joel Fernandes Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Juri Lelli Reviewed-by: Andrea Righi Acked-by: Tejun Heo Tested-by: Christian Loehle Link: https://patch.msgid.link/20260126100050.3854740-4-arighi@nvidia.com --- kernel/sched/debug.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index ed9254da51161..41e389569d06b 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -348,6 +348,8 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu return err; scoped_guard (rq_lock_irqsave, rq) { + bool is_active; + runtime = rq->fair_server.dl_runtime; period = rq->fair_server.dl_period; @@ -370,8 +372,11 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu return -EINVAL; } - update_rq_clock(rq); - dl_server_stop(&rq->fair_server); + is_active = dl_server_active(&rq->fair_server); + if (is_active) { + update_rq_clock(rq); + dl_server_stop(&rq->fair_server); + } retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0); @@ -379,7 +384,7 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n", cpu_of(rq)); - if (rq->cfs.h_nr_queued) + if (is_active && runtime) dl_server_start(&rq->fair_server); if (retval < 0) -- 2.47.3