diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2017-04-21 12:46:57 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-05-15 10:15:21 +0200 |
| commit | 2e44b7ddf8ab01cf98106c68388f87af15fbde73 (patch) | |
| tree | e0bb9507fc4d61957b10858a2caf87e616c7332a /kernel/sched | |
| parent | f9fccdb9efef60dbcf84d493514b475c41aa866f (diff) | |
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>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/clock.c | 10 | ||||
| -rw-r--r-- | kernel/sched/core.c | 2 |
2 files changed, 9 insertions, 3 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index d4c2f89fac92..a2f847c6ada8 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -64,6 +64,7 @@ #include <linux/workqueue.h> #include <linux/compiler.h> #include <linux/tick.h> +#include <linux/init.h> /* * Scheduler clock - returns current time in nanosec units. @@ -202,7 +203,11 @@ void clear_sched_clock_stable(void) __clear_sched_clock_stable(); } -void sched_clock_init_late(void) +/* + * We run this as late_initcall() such that it runs after all built-in drivers, + * notably: acpi_processor and intel_idle, which can mark the TSC as unstable. + */ +static int __init sched_clock_init_late(void) { sched_clock_running = 2; /* @@ -216,7 +221,10 @@ void sched_clock_init_late(void) if (__sched_clock_stable_early) __set_sched_clock_stable(); + + return 0; } +late_initcall(sched_clock_init_late); /* * min, max except they take wrapping into account diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 803c3bc274c4..5794f4acad15 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5984,7 +5984,6 @@ void __init sched_init_smp(void) init_sched_dl_class(); sched_init_smt(); - sched_clock_init_late(); sched_smp_initialized = true; } @@ -6000,7 +5999,6 @@ early_initcall(migration_init); void __init sched_init_smp(void) { sched_init_granularity(); - sched_clock_init_late(); } #endif /* CONFIG_SMP */ |