Re: [PATCH] Fix performance monitor exception in 2.6.20-series

  IMHO, option  #1 is very  nice, as long  as the PMU interrupt  handler behaves
itself.  One reason option #1 is desirable is, with PC-sampling, we are now able
to  sample  regions _inside_  interrupt-disabled  sections  (assuming an  actual
external interrupt  hasn't really occured yet). Before,  with hardware disabling
of  interrupts,  the  PMU  exceptions  were  necessarily  delivered  outside  of
interrupt disabled sections. 

  Anyways, does anyone see a problem with the following patch? 

Well, are you absolutely sure that nothing will break as a result of
having a PMU interrupt happening right when it's not expected to ?

You are basically turning the PMU interrupt into an NMI... I'm not sure
how safe that is.

Ben.