> > For my education, what is the API to send an IPI? > > And the API to handle an IPI? > > There are a few ways you could implement some custom cross-call, > although in this case I think stop_machine() would probably be the most > appropriate candidate. However, you're right that in general it may not > actually help enough to be worthwhile - a DSB SY would ensure that > in-flight transactions have at least been observed by the CPUs and any > other coherent masters, but for any writes with a memory type allowing > early acknowledgement (i.e. a Normal or Device mapping of a BAR) that > doesn't necessarily correlate with them having reached their ultimate > destination. For a PCI destination in particular, I think the normal way > to ensure all posted writes have completed would be to read from config > space; ah... He almost certainly doesn't need to wait for the cycle to complete, just long enough for the cycle to have been sent. David
