Messages in this thread | | | Date | Sun, 15 May 2005 12:36:46 +0200 | From | Andi Kleen <> | Subject | Re: [discuss] Re: [PATCH] adjust x86-64 watchdog tick calculation |
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On Fri, May 13, 2005 at 09:52:15PM +0200, Pavel Machek wrote: > On P? 13-05-05 13:30:23, Andi Kleen wrote: > > > Because it kills machine when interrupt latency gets too high? > > > Like reading battery status using i2c... > > > > That's a bug in the I2C reader then. Don't shot the messenger for bad news. > > Disagreed. > > Linux is not real time OS. Perhaps some real-time constraints "may not > spend > 100msec with interrupts disabled" would be healthy, but it > certainly needs more discussion than "lets enable NMI > watchdog.". It needs to be written somewhere in big bold letters, too.
While linux is not a real time OS it has been always known that turning off interrupts for a long time is extremly rude.
If you really want you can use touch_nmi_watchdog in the delay loop then. But note you have to compile it in, because touch_nmi_watchdog is not exported (Linus vetoed that for good reasons).
But again do you really need to disable interrupts during this i2c access? Can't you just use a schedule_timeout() and a semaphore? Why would other interrupts cause a problem during such a long delay?
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