Regarding Zero write recvfile() performance(splice system call)

[Jeremy Allison]

On Fri, Mar 06, 2015 at 05:28:23PM -0800, Christoph Hellwig wrote:
> On Fri, Mar 06, 2015 at 09:46:01AM -0800, Jeremy Allison wrote:
> > splice is known to have very bad performance in Linux in this
> > case.
> > 
> > The only known patch to fix this I've posted many times on this
> > list (search for it :-). It's considered too ugly by the Linux kernel developers
> > to be integrated into the kernel.
> 
> It's not just ugly, it's also broken in many ways.  I've offered many
> times to implement a proper version on a consulting basis, but not one
> was interested in it once it came with a price tag attached.

Sorry Christoph, I assumed that people understood
ugly == broken in this case (if you search the list
archives you'll find many cases of people pointing
out how this can crash the kernel :-).

I'm hoping if enough people know this exists and
how broken it is, a NAS OEM will eventually step
up and fund you to fix it properly in the kernel.

People need to know about it first though :-).