On Mon, 2007-08-06 at 18:45 +0400, Oleg Nesterov wrote: > On 08/06, Peter Zijlstra wrote: > > > > still this does not change the fundamental issue of a high prio piece of > > work waiting on a lower prio task. > ^^^^^^^ > waiting. This is a "key" word, and this was my (perhaps wrong) point. Actually, I think Peter is making a really important point here. "Waiting" can be defined in more ways than the REQUEST/RESPONSE pattern that I have been rambling about. Using Peters NIC vs USB example: What if a NIC driver is using a workqueue as a bottom-half mechanism for its RX packet queuing. In a nice RT environment it would be highly ideal if we allow the deferred work to complete with respect to the priority that was assigned to the subsystem. So while the submitter isn't technically blocking on the work, the application that is receiving packets is now subject to the arbitrary priority of the keventd as opposed to the NIC irq. Thus there is still "waiting" being subject to inversion, its just not in a REQUEST/RESPONSE pattern. -Greg - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
