From: "Jan Beulich" <JBeulich@suse.com>
To: Lan Tianyu <tianyu.lan@intel.com>
Cc: sstabellini@kernel.org, wei.liu2@citrix.com,
George.Dunlap@eu.citrix.com, andrew.cooper3@citrix.com,
ian.jackson@eu.citrix.com,
xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH] Xen/timer: Disable watchdog during dumping timer queues
Date: Wed, 21 Sep 2016 03:25:06 -0600 [thread overview]
Message-ID: <57E26E120200007800110EB6@prv-mh.provo.novell.com> (raw)
In-Reply-To: <57E1E868.4080802@intel.com>
>>> On 21.09.16 at 03:54, <tianyu.lan@intel.com> 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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next prev parent reply other threads:[~2016-09-21 9:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 7:12 [PATCH] Xen/timer: Disable watchdog during dumping timer queues Lan Tianyu
[not found] ` <57D7DCC2020000780010E553@prv-mh.provo.novell.com>
[not found] ` <c7777159-7863-99fc-76ab-e8f4195286e1@intel.com>
2016-09-13 15:25 ` Jan Beulich
2016-09-15 14:16 ` Lan, Tianyu
2016-09-15 14:32 ` Jan Beulich
2016-09-19 13:57 ` Lan, Tianyu
2016-09-19 14:46 ` Jan Beulich
2016-09-20 14:52 ` Lan, Tianyu
2016-09-20 15:36 ` Jan Beulich
2016-09-21 1:54 ` Lan Tianyu
2016-09-21 9:25 ` Jan Beulich [this message]
2016-09-22 14:18 ` Lan Tianyu
2016-09-22 14:26 ` Jan Beulich
2016-09-22 15:04 ` Lan, Tianyu
2016-09-22 15:35 ` Jan Beulich
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