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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-27 09:03:41 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-27 09:03:41 -0800 |
| commit | 2eeefc60ad70ffb7a5daf9f47aef5b1ebd1f39ad (patch) | |
| tree | 0ebab4a8e90013c61459efb074e80dddc924b571 | |
| parent | 3b80dee70eaa5f9a120db058c30cc8e63c443571 (diff) | |
| parent | f6f5cd840ae782680c5e94048c72420e4e6857f9 (diff) | |
Merge tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
"Update/fix two CPU sanity checks in the hotplug and the boot code, and
fix a typo in the Kconfig help text.
[ Context: the first two commits are the result of an ongoing
annotation+review work of (intentional) tick_do_timer_cpu() data
races reported by KCSAN, but the annotations aren't fully cooked
yet ]"
* tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill"
tick/sched: Remove bogus boot "safety" check
tick: Remove pointless cpu valid check in hotplug code
| -rw-r--r-- | kernel/time/Kconfig | 2 | ||||
| -rw-r--r-- | kernel/time/tick-common.c | 10 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 7 |
3 files changed, 4 insertions, 15 deletions
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 9a41848b6ebb..83e158d016ba 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -141,7 +141,7 @@ config CONTEXT_TRACKING_FORCE dynticks working. This option stands for testing when an arch implements the - context tracking backend but doesn't yet fullfill all the + context tracking backend but doesn't yet fulfill all the requirements to make the full dynticks feature working. Without the full dynticks, there is no way to test the support for context tracking and the subsystems that rely on it: RCU diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index a03764df5366..9d3a22510bab 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -407,17 +407,13 @@ EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); /* * Transfer the do_timer job away from a dying cpu. * - * Called with interrupts disabled. Not locking required. If + * Called with interrupts disabled. No locking required. If * tick_do_timer_cpu is owned by this cpu, nothing can change it. */ void tick_handover_do_timer(void) { - if (tick_do_timer_cpu == smp_processor_id()) { - int cpu = cpumask_first(cpu_online_mask); - - tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu : - TICK_DO_TIMER_NONE; - } + if (tick_do_timer_cpu == smp_processor_id()) + tick_do_timer_cpu = cpumask_first(cpu_online_mask); } /* diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 030282994b3e..e10a4af88737 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -989,13 +989,6 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) */ if (tick_do_timer_cpu == cpu) return false; - /* - * Boot safety: make sure the timekeeping duty has been - * assigned before entering dyntick-idle mode, - * tick_do_timer_cpu is TICK_DO_TIMER_BOOT - */ - if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_BOOT)) - return false; /* Should not happen for nohz-full */ if (WARN_ON_ONCE(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) |