Re: [PATCH] x86/HPET: mask interrupt while changing affinity

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 19/03/13 22:48, Sander Eikelenboom wrote:
> Tuesday, March 19, 2013, 5:00:33 PM, you wrote:
>
>>>>> On 19.03.13 at 16:53, Sander Eikelenboom <linux@eikelenboom.it> wrote:
>>> Could this change have a averse affect on AMD systems ?
>> It shouldn't, ...
>>> With this patch booting the dom0 kernel slowly seems to come to a halt 
>>> (sometime trying to mount rootfs, sometimes a little further trying to bring 
>>> networking up.)
>> ... but apparently does (apart from also having the intended effect
>> of eliminating vector-without-IRQ warnings). But it's not obvious
>> how that would be - after all, the two added calls should be pretty
>> benign performance wise.
>>> I don't see any evident warnings or errors, reverting this commit makes the 
>>> system boot OK again.
>> Does the watchdog work on it? If so, could you see whether enabling
>> that catches something? Or else, do the debug keys still work when
>> the box stopped?
> Yes they still work, and somehow using the debug keys seems to make it continu for a bit (slowly and ending up in infinite loop printing firewall messages)
>
> Serial log attached, hope i have used the debug keys you are interested in, if not please do specify ...
>
> --
> Sander

hpet_msi_mask() flips the Timer Interrupt Enable bit, which causes the
timer not to generate interrupts, but to continue running.

Are we by any chance suffering from a bad interaction of oneshot timers
not being re-armed for exceedingly long periods of time ?

~Andrew


>
>
>> Jan