Re: About bdflush(update) & kernel 2.0

Thomas Quinot (
Tue, 9 Jul 1996 02:33:45 +0200 (MET DST)

> > What you wrote is correct, except for the fact that what you call 'bdflush'
> > is actually 'update'. 'bdflush' is what 'kflushd' was called before being
> > implemented as a kernel thread.
> It doesn't seem to be relevant but for the record: both processes used to
> call (and still do, as explained above) the bdflush system call, only the
> arguments were different.

Indeed. update calls bdflush(2)'s function 1 to sync_old_buffers. Actually
it would only call sync(2) as a fallback if this call to bdflush(2)
failed (note : I may seem to have written something different earlier
in this thread. I read the sources more thouroughly since then :-) ).

> (this one hasn't changed). So which one is more bdflush?

Considering the comments in fs/buffer.c, I would say the answer is
kflushd : bdflush(2)'s function 1 only calls sync_old_buffers,
which has the comment "this function is essentially \"update\"" ;
bdflush() (the routine that constitutes the kflushd thread) also
has the mention "This is the actual bdflush daemon itself."

      Thomas.Quinot@Cuivre.FdN.FR       <URL:http://Web.FdN.FR/~tquinot/>