From: Joel Fernandes <[email protected]>

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.

Acked-by: Tejun Heo <[email protected]>
Reviewed-by: Juri Lelli <[email protected]>
Reviewed-by: Andrea Righi <[email protected]>
Signed-off-by: Joel Fernandes <[email protected]>
---
 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 6cf9be6eea49a..e71f6618c1a6a 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)
                        dl_server_start(&rq->fair_server);
 
                if (retval < 0)
-- 
2.51.2


Reply via email to