[dm-devel] [PATCH v5 01/11] block: make generic_make_request handle arbitrarily sized bios

[Kent Overstreet]

On Tue, Aug 04, 2015 at 01:36:26PM +0200, Christoph Hellwig wrote:
> On Sun, Aug 02, 2015 at 10:58:22PM -0700, Ming Lin wrote:
> > I think the important thing is the late splitting for regular bio.
> > For discard/write_same bio, how about just don't do late splitting?
> 
> I'd hate having to special case them even more.  Especially as the
> discard splitting is nasty and we really don't want to send giant
> discards by default anyway (see Jens' patches to limit discard size
> by default).

Why is it that we don't want to send giant discards? Is it a latency issue?