On Thursday 21 March 2002 12:34 pm, Alan Cox wrote:
> > This why I grabbed all those locks, and did the two sets of IPI's in the
> > tcore patch. Once the runqueue lock is grabbed, even if that process on
> > the
>
> If you IPI holding a lock whats going to happen if while the IPI is going
> across the cpus the other processor tries to grab the runqueue lock and
> is spinning on it with interrupts off ?
Then the at least 2 CPU's would quickly become dead locked on the
synchronization IPI this patch sends at the end of the suspend_other_threads
function call.
Interrupts shouldn't be turned off when grabbing the runqueue lock. Its also
a bad thing if they would happen to be off while calling into to schedule.
I think schedule was designed to be called only while interrupts are turned
on. It BUG's if "in_interrupt" to enforce this.
--mgross
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This archive was generated by hypermail 2b29 : Sat Mar 23 2002 - 22:00:25 EST