On Fri, Feb 26, 2021 at 02:52:22PM -0500, Jeff Hostetler wrote:
> > > - if (fd >= 0)
> > > - err = write_packetized_from_fd(fd, process->in);
> > > - else
> > > + if (fd >= 0) {
> > > + struct packet_scratch_space scratch;
> > > + err = write_packetized_from_fd(fd, process->in, &scratch);
> > > + } else
> > > err = write_packetized_from_buf(src, len, process->in);
> >
> > Isn't this just putting the buffer onto the stack anyway? Your
> > scratch_space struct is really just a big array. You'd want to make
> > it static here, but then we haven't really solved anything. :)
>
> Yeah, I was letting the caller decide how to provide the buffer.
> They could put it on the stack or allocate it once across a whole
> set of files or use a static buffer -- the caller has context for
> what works best that we don't have here. For example, the caller
> may know that is not in threaded code at all, but we cannot assume
> that here.
Yeah, I think it's successfully pushed the problem up to the caller. But
it introduced a _new_ problem in putting the large buffer on the stack.
So if this were "static struct packet_scratch_space scratch", I think
we'd be OK.
And perhaps that would meet your needs (if you just need to call
write_packed_from_fd() in a thread, and not this other caller).
But I do think the heap approach is nice in that it keeps the interface
clean, and I think the performance should be comparable.
> Right, I think it would be fine to malloc it here, but I didn't
> want to assume that everyone would think that.
>
> I'll change it.
Thanks. :)
-Peff
