Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+4
-15
+1
-1
kernel/time/Kconfig
+1
-1
kernel/time/Kconfig
···
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dynticks working.
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This option stands for testing when an arch implements the
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-
context tracking backend but doesn't yet fullfill all the
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+
context tracking backend but doesn't yet fulfill all the
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requirements to make the full dynticks feature working.
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Without the full dynticks, there is no way to test the support
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for context tracking and the subsystems that rely on it: RCU
+3
-7
kernel/time/tick-common.c
+3
-7
kernel/time/tick-common.c
···
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/*
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* Transfer the do_timer job away from a dying cpu.
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*
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-
* Called with interrupts disabled. Not locking required. If
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+
* Called with interrupts disabled. No locking required. If
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* tick_do_timer_cpu is owned by this cpu, nothing can change it.
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*/
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void tick_handover_do_timer(void)
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{
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-
if (tick_do_timer_cpu == smp_processor_id()) {
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-
int cpu = cpumask_first(cpu_online_mask);
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-
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-
tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
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-
TICK_DO_TIMER_NONE;
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}
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+
if (tick_do_timer_cpu == smp_processor_id())
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+
tick_do_timer_cpu = cpumask_first(cpu_online_mask);
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}
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/*
-7
kernel/time/tick-sched.c
-7
kernel/time/tick-sched.c
···
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989
*/
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if (tick_do_timer_cpu == cpu)
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return false;
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-
/*
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* Boot safety: make sure the timekeeping duty has been
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-
* assigned before entering dyntick-idle mode,
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* tick_do_timer_cpu is TICK_DO_TIMER_BOOT
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-
*/
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if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_BOOT))
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-
return false;
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/* Should not happen for nohz-full */
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if (WARN_ON_ONCE(tick_do_timer_cpu == TICK_DO_TIMER_NONE))