sched_ext: Print sub-scheduler disabled log and reason

Take scx_qmap for example, when sub scheduler is attached, there is
'BPF sub-scheduler "qmap" enabled' message, but when detached, the log
is missing. Add a new function to do the log thing, it can be used by
both root scheduler and sub scheduler.

Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Reviewed-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 012ca8bd70fbdf75a04cd5b0cd012501a184790d..229a82900e8f41a161ea248e6f9d14db59361d0d 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -5526,6 +5526,26 @@ static void scx_disable_dump(struct scx_sched *sch)
        sch->dump_disabled = true;
 }
 
+static void scx_log_sched_disable(struct scx_sched *sch)
+{
+       struct scx_exit_info *ei = sch->exit_info;
+       const char *type = scx_parent(sch) ? "sub-scheduler" : "scheduler";
+
+       if (ei->kind >= SCX_EXIT_ERROR) {
+               pr_err("sched_ext: BPF %s \"%s\" disabled (%s)\n", type,
+                      sch->ops.name, ei->reason);
+
+               if (ei->msg[0] != '\0')
+                       pr_err("sched_ext: %s: %s\n", sch->ops.name, ei->msg);
+#ifdef CONFIG_STACKTRACE
+               stack_trace_print(ei->bt, ei->bt_len, 2);
+#endif
+       } else {
+               pr_info("sched_ext: BPF %s \"%s\" disabled (%s)\n", type,
+                       sch->ops.name, ei->reason);
+       }
+}
+
 #ifdef CONFIG_EXT_SUB_SCHED
 static DECLARE_WAIT_QUEUE_HEAD(scx_unlink_waitq);
 
@@ -5696,6 +5716,8 @@ static void scx_sub_disable(struct scx_sched *sch)
                            &sub_detach_args);
        }
 
+       scx_log_sched_disable(sch);
+
        if (sch->ops.exit)
                SCX_CALL_OP(sch, exit, NULL, sch->exit_info);
        kobject_del(&sch->kobj);
@@ -5707,7 +5729,6 @@ static void scx_sub_disable(struct scx_sched *sch) { }
 
 static void scx_root_disable(struct scx_sched *sch)
 {
-       struct scx_exit_info *ei = sch->exit_info;
        struct scx_task_iter sti;
        struct task_struct *p;
        int cpu;
@@ -5797,22 +5818,10 @@ static void scx_root_disable(struct scx_sched *sch)
        scx_idle_disable();
        synchronize_rcu();
 
-       if (ei->kind >= SCX_EXIT_ERROR) {
-               pr_err("sched_ext: BPF scheduler \"%s\" disabled (%s)\n",
-                      sch->ops.name, ei->reason);
-
-               if (ei->msg[0] != '\0')
-                       pr_err("sched_ext: %s: %s\n", sch->ops.name, ei->msg);
-#ifdef CONFIG_STACKTRACE
-               stack_trace_print(ei->bt, ei->bt_len, 2);
-#endif
-       } else {
-               pr_info("sched_ext: BPF scheduler \"%s\" disabled (%s)\n",
-                       sch->ops.name, ei->reason);
-       }
+       scx_log_sched_disable(sch);
 
        if (sch->ops.exit)
-               SCX_CALL_OP(sch, exit, NULL, ei);
+               SCX_CALL_OP(sch, exit, NULL, sch->exit_info);
 
        scx_unlink_sched(sch);