sched/clock: Use late_initcall() instead of sched_init_smp()

Core2 marks its TSC unstable in ACPI Processor Idle, which is probed
after sched_init_smp(). Luckily it appears both acpi_processor and
intel_idle (which has a similar check) are mandatory built-in.

This means we can delay switching to stable until after these drivers
have ran (if they were modules, this would be impossible).

Delay the stable switch to late_initcall() to allow these drivers to
mark TSC unstable and avoid difficult stable->unstable transitions.

Reported-by: Lofstedt, Marta <marta.lofstedt@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2017-04-21 12:46:57 +02:00
committed by Ingo Molnar
parent f9fccdb9ef
commit 2e44b7ddf8
3 changed files with 9 additions and 8 deletions

View File

@@ -23,10 +23,6 @@ extern u64 sched_clock_cpu(int cpu);
extern void sched_clock_init(void);
#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
static inline void sched_clock_init_late(void)
{
}
static inline void sched_clock_tick(void)
{
}
@@ -53,7 +49,6 @@ static inline u64 local_clock(void)
return sched_clock();
}
#else
extern void sched_clock_init_late(void);
extern int sched_clock_stable(void);
extern void clear_sched_clock_stable(void);