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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. v2: do not start the server if runtime is zero (Juri Lelli) Tested-by: Christian Loehle Acked-by: Tejun Heo Reviewed-by: Juri Lelli Reviewed-by: Andrea Righi Signed-off-by: Joel Fernandes --- 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 93f009e1076d8..dd793f8f3858a 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -354,6 +354,8 @@ 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; @@ -376,8 +378,11 @@ 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); @@ -385,7 +390,7 @@ 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) -- 2.52.0