Re: [tip:x86/pat] generic-ipi: Allow cpus not yet online to callsmp_call_function with irqs disabled

[Suresh Siddha]

On Mon, 2009-08-24 at 21:29 -0700, Nick Piggin wrote:
> On Mon, Aug 24, 2009 at 01:15:43PM -0700, Suresh B wrote:
> > On Sun, 2009-08-23 at 22:40 -0700, Nick Piggin wrote:
> > > Also, I would say that we should just restrict this to wait==1 case
> > > because in that case the stack can trivially be used for data. In
> > > the wait==0 case, it is more complex. In the current implementation
> > > it should be OK (it uses per-cpu data), but we've used kmalloc
> > > there in the past, which probably wouldn't work either.
> > 
> > In future if we add any kmalloc, we already have checks in kmalloc()
> > that can be easily caught. I would like to make this change as generic
> > as possible.
> 
> Why? You think there will be much demand for it?

In the current mtrr case, we currently use wait==0

Also unless there are issues, I would like to keep it open. So that it
will encourage more usages and expose any other bugs that we perhaps
overlooked.

With all the recent generic-ipi changes, even for online cpu's, we
should be able to allow smp_call_function() with interrupts disabled for
wait==0 case, right?

thanks,
suresh

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