Re: sched: system doesn't boot since "sched: Add new migrate_disable() implementation"

[Peter Zijlstra]

On Mon, Oct 19, 2020 at 05:09:35PM +0200, Sebastian Andrzej Siewior wrote:
> On 2020-10-19 12:21:06 [+0200], Christian Eggers wrote:
> > I have problems with the latest 5.9-rt releases on i.MX6ULL (!CONFIG_SMP):
> > 
> …
> > Any hints?
> 
> Thank you for the report. The reason is the migrate_disable()
> implementation for !SMP.

This should fix things I suppose. I'll fold it in.

---
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -378,7 +378,12 @@ static inline void preempt_notifier_init
 extern void migrate_disable(void);
 extern void migrate_enable(void);
 
-#else /* !(CONFIG_SMP && CONFIG_PREEMPT_RT) */
+#elif defined(CONFIG_PREEMPT_RT)
+
+static inline void migrate_disable(void) { }
+static inline void migrate_enable(void { }
+
+#else /* !CONFIG_PREEMPT_RT */
 
 /**
  * migrate_disable - Prevent migration of the current task