Hitachi djprobe mechanism

[Andi Kleen]

On Wed, Aug 03, 2005 at 08:26:56PM -0400, Mathieu Desnoyers wrote:
> * Roland McGrath (roland@redhat.com) wrote:
> > It's OK for probe insertion to be slow.  So why not use RCU to synchronize
> > other processors?
> > 
> 
> No,
> 
> The reason is we have no control on preemption disabling around the concerned
> area.

Task list walking and checking of the IP of blocked processes can avoid that
as earlier discussed. But it doesn't solve all problems with short instructions.
IPI is the most practical one.

-Andi (who thinks this discussion is running in circles now)