Re: Obsolete bdflush system call?

"Also sprach Bas van Schaik:"
> Just after starting the enbd-client, the kernel complains about an
> obsolete bdflush system call:

That's fine - don't worry about it. Some kernels support it, others
don't. I guess I should try and find out what to use if they don't.

> > Mar 18 02:13:55 localhost kernel: warning: process `enbd-client' used the obsolete bdflush system call

> In nbd/config.h.in, the following appears:
> > /* Define if you have the bdflush function.  */
> > #undef HAVE_BDFLUSH
> 
> I don't really understand why this is done, but HAVE_BDFLUSH is only
> used in enbd-client.c.

It's done to lower the time-to-age-to-disk of buffers, to prevent
buffers aimed at enbd from building up in memory, thus strangling the
network (tcp needs buffers) and preventing enbd from flushing buffers
out through the net ...

The kernel needs some mechanism to help it control memory use. One has
to guess.

Peter