On 09/19/2011 04:54 PM, Marcelo Tosatti wrote:
> >>
> >> Yes, due to NMI-blocked-by-STI. A really touchy area.
> >And we don't need the window exit notification then? I don't understand
> >what nmi_in_progress is supposed to do here.
>
> We need the window notification in both cases. If we're recovering
> from STI, then we don't need to collapse NMIs. If we're completing
> an NMI handler, then we do need to collapse NMIs (since the queue
> length is two, and we just completed one).
I don't understand what is the point with nmi_in_progress, and the above
hunk, either. Can't inject_nmi do:
if (nmi_injected + atomic_read(nmi_pending)< 2)
atomic_inc(nmi_pending)
Instead of collapsing somewhere else?
We could. It's not atomic though - two threads executing in parallel
could raise the value to three. Could do a cmpxchg loop does an
increment bounded to two. I guess this is a lot clearer, thanks.
You'd also have to change
nmi_injected handling in arch code so its value is not "hidden", in
complete_interrupts().
Or maybe make raising nmi_injected not decrement nmi_pending. So:
nmi_pending: total number of interrupts in queue
nmi_injected: of these, how many are currently being injected
yes?
--
error compiling committee.c: too many arguments to function
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