spin_lock and scheduler confusion

Dave Hylands dhylands at gmail.com
Fri Jan 7 10:51:00 EST 2011

Hi Nilesh.

Using reply all this time...

On Thu, Jan 6, 2011 at 10:27 PM, Tayade, Nilesh
<Nilesh.Tayade at netscout.com> wrote:
>> You shouldn't be holding  a spinlock for periods of time approaching
>> the length of a timeslice. The timer interrupt is what determines the
>> end of a timeslice. No timer interrupt, no end of a timeslice.
>> Preemption is also triggered by the timer interrupt, or by releasing a
>> resource that a higher priority task is waiting for.
> May be my understanding is incorrect, but wouldn't we hit the NMI watchdog here(assuming we are running on x86/x86_64)?
> We have a system lockup for long time.
> http://lxr.linux.no/#linux+v2.6.37/Documentation/nmi_watchdog.txt
> Could someone please clarify?

Did you enable it by passing in nmi_watchdog=1 on the kernel command
line? (and verify that it was working fine - as described in the
nmi__watchdog.txt file)

Dave Hylands

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