Re: [Xen-ia64-devel] [PATCH] fix oops message from timer_interrupt on VTI domain

[Alex Williamson <alex.williamson@xxxxxx>]

On Tue, 2007-01-23 at 16:44 -0500, Aron Griffis wrote:
> Atsushi SAKAI wrote:  [Mon Jan 22 2007, 07:36:55PM EST]
> > Oops: timer tick before it's due (itc=ed98bb5849,itm=ed98bb5849)
> > Oops: timer tick before it's due (itc=f20bca8ca3,itm=f20bca8ca3)
> > Oops: timer tick before it's due (itc=f4ea4e2b32,itm=f4ea4e2b32)
> ...
> > 
> > These oops messages are generated
> > because timer_interrupt checks the condition itc > itm.
> 
> Is that the right comparison though?  itc isn't guaranteed to return
> different values on subsequent fetches, and the interrupt is generated
> when itc == itm, right?  So shouldn't the condition be itc >= itm?

   Good point.  With the slower ITC on a Montecito system, I don't know
if anything would prevent you hitting the interrupt handler when itc ==
itm.  Perhaps a Montecito fix for Linux-ia64 to use time_after_eq()
would eliminate this problem.

        Alex
-- 
Alex Williamson                             HP Open Source & Linux Org.


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