On Mon, 2009-11-23 at 01:36 -0800, Peter P Waskiewicz Jr wrote:
This mechanism isn't going to be used by any internal kernel mechanism
for determining interrupt placement or operation. It's purely something
that either a driver can modify, or external script (through /proc),
that irqbalance will make use of. If irqbalance isn't running, or the
current version of irqbalance doesn't support reading node_affinity,
then it won't affect the system's operation.
If irqbalance does support it, it'll read whatever the supplied mask is,
and then will try and balance interrupts within that mask. It will bail
if the mask is invalid, or won't apply to the running system, just like
how putting a bogus mask into smp_affinity is ignored.
If there's something I'm missing beyond this with the two suggestions
you've made (I looked into those two parameters and tried to draw
conclusions), please let me know.
I don't see the point in adding it, if the driver wants to set a node
cpu mask it can already do that using the regular smp affinity settings.
Same for userspace.