On Fri, Aug 14, 2009 at 02:53:03PM -0700, Darren Reed wrote: > > > >I understand that with this flag the mpi_fn() has read-only semantics. > >my worry is that at some point some code (maybe not bpf) may try > >to queue the mp instead of completely processing it in the context > >of mpi_fn(). this is definitely not allowed because mp could be freed > >from the real datapath. the danger with callbacks is you can't tell > >how deep they run and you can't guarantee they obey certain retrictions > >throughout. > > > > If the mac API's were a committed set of API's to use, then the thing > to do would be to document the behaviour required by the flag so > that it would be clear when it was appropriate to use it. > > The way I read your comment, you are arguing for the code to be > slower because someone might write buggy code that uses this flag. >
no, that's not it. my opinion is in certain cases consistency is more important than performance, especially framework level code. what's being introduced is inconsistent not only with the mac, but with many other callback related code throughout the ip stack. that's my main concern. anyway if you really want to keep it I'm fine. if you have some ballpark numbers about the performance cost I'd like to have them. eric
