Re: [Xen-devel] [PATCH] Xen/timer: Disable watchdog during dumping timer queues

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 21.09.16 at 03:54, <tianyu.lan@xxxxxxxxx> wrote:
> On 2016年09月20日 23:36, Jan Beulich wrote:
>>> The precondition of process_pending_softirq() working in the debug key
>>> > handler is that timer interrupt arrives on time and nmi_timer_fn() can
>>> > run to update nmi_timer_ticks before watchdog timeout.
>> Precondition?
> 
> Process_pending_softirq() in debug key handler is mainly to deal with
> timer softirq to update nmi_timer_ticks in order to avoid NMI watchdog.
> If there is no timer interrupt arriving for long time,
> process_pending_softirq() here is meaningless and NMI watchdog still
> will be timeout.

Oh, right. Still I continue to be unconvinced that disabling the
watchdog is the right answer (not running timers for a long time
has other undesirable consequence), or if it is, then it being
needed in only this one key handler. So perhaps you should
really consider submitting your generic key handler adjustment
as an alternative.

But please also answer the earlier question, which you did strip
from your reply:

>Which btw raises another question: Why are you in polling mode in
>the first place? Do you have a UART without working interrupt?

Jan

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