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SubjectRe: [patch 1/2] Ignore stolen time in the softlockup watchdog
Eric Dumazet wrote:
> Jeremy Fitzhardinge a écrit :
>
>> +static DEFINE_PER_CPU(unsigned long long, touch_timestamp);
>
> ...
>
>> void touch_softlockup_watchdog(void)
>> {
>> - __raw_get_cpu_var(touch_timestamp) = jiffies;
>> + __raw_get_cpu_var(touch_timestamp) = sched_clock();
>> }
>
> Not very clear if this is safe on 32bit, since this is not anymore
> atomic.

Hm, good point. Don't think it matters very much. These values are
per-cpu, and if an interrupt happens between the word updates and the
intermediate values causes a timeout, then it was pretty marginal
anyway. I guess the worst case is if the low-word gets written first,
and it goes from a high value to low, then it could be sampled as if
time had gone back by up to ~4 seconds.

I'll give it another look.

J
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